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Volume 103-B, Issue SUPP_3 March 2021 The Canadian Orthopaedic Association (COA) and Canadian Orthopaedic Research Society (CORS) Virtual Annual Meeting 2020, held online, 19–20 June 2020.

M. Taha J.M. Werier H. Abdelbary

Periprosthetic joint infection (PJI) remains one of the most devastating complications that can occur following total joint arthroplasty. Failure rate of standard treatment for PJI is estimated to be around 40% at two years post revision surgery. A major clinical challenge contributing to treatment failure and antibiotics tolerance is the biofilm formation on implant surfaces. Lytic bacteriophages (phages) can target biofilm associated bacteria at localized sites of infection by penetrating and disrupting biofilm matrices; furthermore, phage replication within the biofilm leads to high local concentrations resulting in a powerful therapeutic effect. The aim of this study is to test if phage cocktail has better antimicrobial effect than vancomycin or a single agent phage against biofilm forming MRSA clinical strain Staphylococcus aureus (S. aureus).

S. aureus BP043 was utilized in this study. This strain is a PJI clinical isolate, methicillin resistant (MRSA) and biofilm-former. Three lytic phages, namely, 44AHJD, Team1 and P68, known to infect S. aureus, were tested for their efficiency against S. aureus BP043. The ability of the phages to eliminate S. aureus BP043 planktonic or biofilm cultures was tested either as singular phages or as a cocktail of the three phages. Planktonic cells were adjusted to ∼ 1×109 CFU/mL in tryptic soy broth (TSB) and each phage was added alone or as a cocktail at ∼ 1×109 PFU/mL with moi of 1 (a multiplicity of infection). Bacterial growth was assessed by measuring optical densities at 24hr and was compared to the control of S. aureus BP043 with no phage. BP043 biofilms was grown for 24hr on plasma sprayed titanium (Ti-6Al-4V) alloy disc surfaces. Mature biofilms were then treated with one of the three phages or a cocktail of the 3 phages for 24hr at ∼ 1×109 PFU/mL in TSB. Then, biofilms were dislodged, and bacterial survival was assessed by plating on tryptic soy agar plates. Survival in treated biofilms was compared to control biofilm that was exposed only to TSB.

Planktonic cells growth in the presence of phage 44AHJD was reduced significantly (p <0.0001) after 24hr compared to the control. The other two phages did not show a similar pattern when used alone. The reduction in growth was more pronounced when the three phages were combined together (p <0.0001, compared to the control, p=0.011 3, 44AHJD alone versus 3 phages). Exposing BP043 biofilm to the phage cocktail resulted in more than three logs (CFU/mL) reduction in bacterial load residing in the biofilm while no effect was detected when either vancomycin or each phage was used solely.

We have demonstrated that the usage of lytic phage cocktail contributes to better clearance of planktonic cultures of the S. aureus MRSA isolate. More importantly, viable bacteria in the biofilms that were grown on plasma sprayed titanium discs were reduced by more than 37% when a phage cocktail was used compared to using a single phage or vancomycin. This work is aimed at gathering preclinical evidence for using phage as a new therapeutic avenue to treat PJI.


A. Changoor R.P. Suderman I. Alshaygy A. Fuhrmann M. Akens O. Safir M. Grynpas P. Kuzyk

Patients undergoing revision surgery of a primary total hip arthroplasty often exhibit bone loss and poor bone quality, which make achieving stable fixation and osseointegration challenging. Implant components coated in porous metals are used clinically to improve mechanical stability and encourage bone in-growth. We compared ultra-porous titanium coatings, known commercially as Gription and Porocoat, in an intra-articular model by press-fitting coated cylindrical implants into ovine femoral condyles and evaluating bone in-growth and fixation strength 4, 8 and 16 weeks post-operatively.

Bilateral surgery using a mini-arthrotomy approach was performed on twenty-four Dorset-Rideau Arcott rams (3.4 ± 0.8 years old, 84.8 ± 9.3 kg) with Institutional Animal Care Committee approval in accordance with the Canadian Council on Animal Care. Cylindrical implants, 6.2 mm in diameter by 10 mm in length with surface radius of curvature of 35 mm, were composed of a titanium substrate coated in either Porocoat or Gription and press-fit into 6 mm diameter recipient holes in the weight-bearing regions of the medial (MFC) and lateral (LFC) femoral condyles. Each sheep received 4 implants; two Gription in one stifle (knee) and two Porocoat in the contralateral joint. Biomechanical push-out tests (Instron ElectroPuls E10000) were performed on LFCs, where implants were pushed out relative to the condyle at a rate of 2 mm/min. Force and displacement data were used to calculate force and displacement at failure, stiffness, energy, stress, strain, elastic modulus, and toughness. MFCs were fixed in 70% ethanol, processed undecalcified, and polished sections, approximately 70 µm thick (Exakt Micro Grinding system) were carbon-coated. Backscattered electron images were collected on a scanning electron microscope (Hitachi SU3500) at 5 kV and working distance of 5 mm. Bone in-growth within the porous coating was quantified using software (ImageJ). Statistical comparisons were made using a two-way ANOVA and Fisher's LSD post-hoc test (Statistica v.8).

Biomechanical evaluation of the bone-implant interface revealed that by 16 weeks, Gription-coated implants exhibited higher force (2455±1362 N vs. 1002±1466 N, p=0.046) and stress (12.60±6.99 MPa vs. 5.14±7.53 MPa, p=0.046) at failure, and trended towards higher stiffness (11510±7645 N/mm vs. 5010±8374 N/mm, p=.061) and modulus of elasticity (591±392 MPa vs. 256±431 MPa, p=0.61). Similarly, by 16 weeks, bone in-growth in Gription-coated implants was approximately double that measured in Porocoat (6.73±3.86 % vs. 3.22±1.52 %, p=0.045). No statistically significant differences were detected at either 4 nor 8 weeks, however, qualitative observations of the exposed bone-implant interface, made following push-out testing, showed more bony material consistently adhered to Gription compared to Porocoat at all three time points. High variability is attributed to implant placement, resulting from the small visual window afforded during surgery, unique curvatures of the condyles, and presence of the extensor digitorum longus tendon which limited access to the LFC.

Ultra-porous titanium coatings, know commercially as Gription and Porocoat, were compared for the first time in a challenging intra-articular ovine model. Gription provided superior fixation strength and bone in-growth, suggesting it may be beneficial in hip replacement surgeries where bone stock quality and quantity may be compromised.


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S.M. Ge L. Hadidi M. Comeau-Gauthier J. Ramirez-GarciaLuna G. Merle E. Harvey

Fracture non-union can be as high as 20% in certain clinical scenarios and has a high associated socioeconomic burden. Boron has been shown to regulate the Wnt/β-catenin pathway in other bodily processes. However, this pathway is also critical for bone healing. Here we aim to demonstrate that the local delivery of boric acid can accelerate bone healing, as well as to elucidate how boric acid, via the regulationtheWnt/β-catenin pathway, impacts theosteogenic response of bone-derived osteoclasts and osteoblasts during each phase of bone repair.

Bilateral femoral cortical defects were created in 32 skeletally mature C57 mice. On the experimental side, boric acid (8mg/kg concentration) was injected locally at the defect site whereas on the control side, saline was used. Mice were euthanized at 7, 14, and 28 days. MicroCT was used to quantify bone regeneration at the defect. Histological staining for ALP and TRAP was used to quantify osteoblast and osteoclast activity respectively. Immunohistochemical antibodies, β-catenin and CD34 were used to quantify active β-catenin levels and angiogenesis respectively. Sclerostin and GSK3β were also quantified and are both inhibitors of the wnt signaling pathway via degradation and inactivation of β-catenin.

The boron group exhibited higher bone volume and trabecular thickness at the defect site by 28 days on microCT. ALP activity was significantly higher in boron group at 7 days whereas boron had no effect on TRAP activity. Additionally, CD34 staining revealed increased angiogenesis at 14 days in boron treated groups. β-catenin activity on immunohistochemistry was significantly higher in the boron group at 7 days, GSK3β was significantly higher in the boron group at 14 days and Sclerostin was significantly higher in the boron group at 28 days.

Boron appears to increase osteoblast activity at the earlier phases of healing. The corresponding early increase in β-catenin along with ALP likely supports that boron increases osteoblast activity via the wnt/β-catenin pathway. Increased angiogenesis at 14 days could be a separate mechanism increasing bone formation independent of wnt/β-catenin activation. Neither GSK3β or Sclerostin levels correlated with β-catenin activity therefore boron likely increases β-catenin through a mechanism independent of both GSK3β and Sclerostin. The addition of this inexpensive and widely available ion could potentially become a non-invasive, cost-effective treatment modality to augment fracture healing and decrease non-union rates in high risk patients.


S. Werdyani M. Liu Z. Xie A. Furey Z. Gao P. Rahman G. Zhai

Total joint replacement (TJR) is by far the most effective therapy for end-stage OA patients. Most of patients achieve joint pain reduction and function improvement following to TJR, however up to 22% of them either do not improve or deteriorate after surgery. The aim of this study was to identify genetic variants to be associated with poor outcome of TJR in primary OA patients by a genome-wide association approach (GWAS).

Study participants were primary OA patients from the Newfoundland Osteoarthritis Study (NFOAS) that comprised total knee or hip replacement and recruited before 2016 in St. John's, NL. DNA samples were extracted from patients' blood. Study participants completed their pre-operation and 3.99±1.38 years post-surgery outcome assessment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). DNA samples were genotyped using the genome-wide Illumina HumanOmni2.58 genotyping microarray containing 2.4 million SNPs. Pre-association quality control filtering was conducted for the raw genotyping data using PLINK 1.7 program, and genotype imputation was performed using the IMPUTE2 algorithm with multiple population reference data from 1000 Genome Project. The imputed data with ∼3.1 million variants was used to test the association with non-responders to TJR using the additive genetic model.

Eighty three primary OA patients (44 responders and 39 non-responders) were included in the analysis. Association analysis detected three chromosomal regions on chr5, 7, and 8 to be significantly associated with non-responding to pain. The top SNPs at these loci are intergenic variants that include SNP (rs17118094, p=4.4×10-5) on chr5. This SNP is adjacent to SGCD gene that plays an important role in muscular strength and maintenance. Another associated SNP (rs71572810, p=4.7×10-5) is nearby IMMP2L gene on chr7. This gene is reported to be associated with behavioral abnormalities. Finally, SNP (rs6992938, p=5.8×10-5) on chr8 is located downstream of TRPA1 gene that is known to have a central role in the pain response to endogenous inflammatory mediators. Three loci were also found to be significantly associated with non-responding to function. The lead variant in the locus on chr1 is an intergenic SNP (rs9729377, p=1.7×10-5) falling between CTBS and MCOLN2 genes. CTBS gene is associated with TNF-α, a cytokine that stimulate the inflammation acute phase reaction, and MCOLN2 gene plays a role in the chemokine secretion and macrophage migration in the innate immune response. Other top SNPs in loci on chr2 and 10 harbor CCDC93, INSIG2, and KLF6 genes that are associated with heel bone mineral density, hypercholesterolemia, obesity and BMI.

To our knowledge, this project is the first study that investigated the association between genetic factors and TJR non-responders. Our results demonstrated that genes related to muscle strength, behavioral trait, pain response, and inflammation play a significant role in poor outcome of TJR, warranting further investigation.


M. Mohtajeb J. Cibere H. Zhang D. Wilson

Femoroacetabular impingement (FAI) deformities are a potential precursor to hip osteoarthritis and an important contributor to non-arthritic hip pain. Some hips with FAI deformities develop symptoms of pain in the hip and groin that are primarily position related. The reason for pain generation in these hips is unclear. Understanding potential impingement mechanisms in FAI hips will help us understand pain generation. Impingement between the femoral head-neck contour and acetabular rim has been proposed as a pathomechanism in FAI hips. This proposed pathomechanism has not been quantified with direct measurements in physiological postures. Research question: Is femoroacetabular clearance different in symptomatic FAI hips compared to asymptomatic FAI and control hips in sitting flexion, adduction, and internal rotation (FADIR) and squatting postures?

We recruited 33 participants: 9 with symptomatic FAI, 13 with asymptomatic FAI, and 11 controls from the Investigation of Mobility, Physical Activity, and Knowledge Translation in Hip Pain (IMAKT-HIP) cohort. We scanned each participant's study hip in sitting FADIR and squatting postures using an upright open MRI scanner (MROpen, Paramed, Genoa, Italy). We quantified femoroacetabular clearance in sitting FADIR and squatting using beta angle measurements which have been shown to be a reliable surrogate for acetabular rim pressures. We chose sitting FADIR and squatting because they represent, respectively, passive and active maneuvers that involve high flexion combined with internal/external rotation and adduction/abduction, which are thought to provoke impingement.

In the squatting posture, the symptomatic FAI group had a significantly smaller minimum beta angle (−4.6º±15.2º) than the asymptomatic FAI (12.5º ±13.2º) (P= 0.018) and control groups (19.8º ±8.6º) (P=0.001). In the sitting FADIR posture, both symptomatic and asymptomatic FAI groups had significantly smaller beta angles (−9.3º ±14º [P=0.010] and −3.9º ±9.7º [P=0.028], respectively) than the control group (5.7º ±5.7º).

Our results show loss of clearance between the femoral head-neck contour and acetabular rim (negative beta angle) occurred in symptomatic FAI hips in sitting FADIR and squatting. We did not observe loss of clearance in the asymptomatic FAI group for squatting, while we did observe loss of clearance for this group in sitting FADIR. These differences may be due to accommodation mechanisms in the active, squatting posture that are not present in the passive, sitting FADIR posture. Our results support the hypothesis that impingement between the femoral head-neck contour and acetabular rim is a pathomechanism in FAI hips leading to pain generation.


D.J. Stockton A. Schmidt A. Yung J. Desrochers H. Zhang B. Masri D.R. Wilson

It is unclear why ACL rupture increases osteoarthritis risk, regardless of ACL reconstruction. Our aims were: 1) to establish the reliability and accuracy of a direct method of determining tibiofemoral contact in vivo with UO-MRI, 2) to assess differences in knees with ACL rupture treated nonoperatively versus operatively, and 3) to assess differences in knees with ACL rupture versus healthy knees.

We recruited a convenience sample of patients with prior ACL rupture. Inclusion criteria were: 1) adult participants between 18–50 years old; 2) unilateral, isolated ACL rupture within the last five years; 3) if reconstructed, done within one year from injury; 4) intact cartilage; and 5) completed a graduated rehabilitation program culminating in return to sport or recreational activities. Participants were excluded if they had other ligament ruptures, osteoarthritis, an incompletely rehabilitated injury, were prohibited from undergoing MRI, or had a history of ACL re-rupture. Using the UO-MRI, we investigated tibiofemoral contact area, centroid location, and six degrees of freedom alignment under standing, weightbearing conditions with knees extended. We compared patients with ACL rupture treated nonoperatively versus operatively, and ACL ruptured knees versus healthy control knees. We assessed reliability using the intra-class correlation coefficient, and accuracy by comparing UO-MRI contact area with a 7Tesla MRI reference standard. We used linear mixed-effects models to test the effects of ACL rupture and ACL reconstruction on contact area. We used a paired t test for centroid location and alignment differences in ACL ruptured knees versus control knees, and the independent t test for differences between ACL reconstruction and no reconstruction. Analyses were performed using R version 3.5.1. We calculated sample size based on a previous study that showed a contact area standard deviation of 13.6mm2, therefore we needed eight or more knees per group to detect a minimum contact area change of 20mm2with 80% power and an α of 0.05.

We recruited 18 participants with ACL rupture: eight treated conservatively and 10 treated with ACL reconstruction. There were no significant differences between the operative and nonoperative ACL groups in terms of age, gender, BMI, time since injury, or functional knee scores (IKDC and KOOS). The UO-MRI demonstrated excellent inter-rater, test-retest, and intra-rater reliability with ICCs for contact area and centroid location ranging from 0.83–1.00. Contact area measurement was accurate to within 5% measurement error. At a mean 2.7 years after injury, we found that ACL rupture was associated with a 10.4% larger medial and lateral compartment contact areas (P=0.001), with the medial centroid located 5.2% more posterior (P=0.001). The tibiae of ACL ruptured knees were 2.3mm more anterior (P=0.003), and 2.6° less externally rotated (P=0.010) relative to the femur, than contralateral control knees. We found no differences between ACL reconstructed and nonreconstructed knees.

ACL rupture was associated with significant mechanical changes 2.7 years out from injury, which ACL reconstruction did not restore. These findings may partially explain the equivalent risk of post-traumatic osteoarthritis in patients treated operatively and nonoperatively after ACL rupture.


L. Heinrichs L. Beaupre A. Ramadi S.H. Hyun Kang E. Pedersen

Decreased ankle dorsiflexion is common after injury and may result in patient complaints of stiffness and subsequent injury. The weight-bearing lunge test (WBLT) is a simple clinical measure of dorsiflexion. Previous study has defined a 2.0cm side-to-side discrepancy in WBLT as likely significant. With review of current literature, ankle stiffness is a concept largely undefined; we aim to relate patient complaints of stiffness to WBLT.

This was a population-based inception cohort with longitudinal follow-up. Patients between ages 18–65 receiving surgical fixation for ankle fracture were screened. Pilon/plafond fractures, bilateral injuries, or polytrauma were excluded. At 6-weeks, 6-months, and 1-year WBLT was measured along with non-weight-bearing goniometry; and an Olerud-Molander ankle score completed.

155 patients were recruited (90 female, 65 male; mean age 42, range 20–67). 47% of injuries were unimalleolar, 17% bimalleolar, and 36% trimalleolar; 35% received syndesmotic fixation. 89% of patients reported feeling stiff at 6-weeks, 82% at 6-months, and 74% at 1-year. 98% of patients had ≥2.0cm discrepancy of WBLT at 6-weeks, 78% at 6-months, and 72% at 1-year. Different thresholds of WBLT (larger discrepancy or absolute negative measurement) had worse correlation with patient reported stiffness.

Our population had high incidence of stiffness at 1-year. The proportion of patients complaining of stiffness after ankle fracture was similar to that measured with ≥2.0cm discrepancy of WBLT. This is the first study that we are aware of that relates the WBLT and the previously reported threshold of 2.0cm to stiffness. This measurement may give clinicians a better objective idea regarding patient perception of a “stiff” ankle. Reducing side to side discrepancy in range of motion should be considered in rehabilitation rather than total range of motion.


D. Dimnjakovic

A tourniquet is usually used during ankle arthroscopy to allow for improved visibility and reduced operation time. However, clinical studies on knee arthroscopy have not demonstrated this to be true. In addition, Zengerink and van Dijk emphasized a limited tourniquet time in ankle arthroscopy as a possible factor to lower the complication rate even more. The purpose of this prospective randomized controlled trial was to examine the effect of tourniquet use on arthroscopic visualization, operative time, postoperative intra-articular bleeding, postoperative pain scores and outcome of anterior ankle arthroscopy.

A consecutive series of 50 patients who were scheduled for anterior ankle arthroscopy were randomized to have the surgery done either without the tourniquet inflated (25 patients) or with the tourniquet inflated (25 patients). The patients were evaluated by the course of the surgery, postoperative intra-articular bleeding, pain during the early postoperative period and by using the subjective and objective functional scores to evaluate the condition of the ankle before and 3 and 6 months after the surgery. The statistical analysis was performed with the normality of distribution tested by both Kolmogorov-Smirnov and Shapiro-Wilk tests. Appropriate parametric or non-parametric methods were then used to test statistical hypotheses, while the statistical significance (alpha, Type I error) was set at .05.

Fourty-nine patients were present at the final follow-up, 6 months after the surgery. The results between the groups were comparable regarding the duration of the operative procedure, consumption of sterile saline, visualisation and functional scores. Notable difference between the groups in favour of the non-tourniquet group was present regarding postoperative bleeding, but was not statistically significant. Statistically significant difference in favour of the non-tourniquet group was found regarding postoperative pain during several days in the early postoperative period.

Our study has shown that anterior ankle arthroscopy may be performed adequately without the use of a tourniquet and that it has the same operative course as in cases in which the tourniquet is used and functional outcomes which are not worse than in cases in which the tourniquet is used.


O. Gagne A. Veljkovic K. Wing M. Penner A.S.E. Younger

Recent advances in arthroplasty for the hip and the knee have motivated modern foot and ankle research to perfect the implant and technique for the optimal total ankle replacement. Unlike in the hip where different approaches can be done with similar implants, the approach of a total ankle is intimately associated to the prosthetic design. The anterior and lateral approaches have pros and cons regarding their respective soft tissue complications, osteotomy necessity, orientation of the bone cut and gutter visualization. While both have been studied independently, very few reports have compared both in the same setting. This study retrospectively looked at the difference in reoperations rate after each ankle arthroplasty within two years estimating that both had similar rate of return to the operating room.

A retrospective study was conducted from a single center between 2014 and 2017 including a total of 115 total ankles performed by one of four fellowship-trained foot and ankle surgeon. Re-operations were reported in the charts as an operative report. The index approach used was determined by the surgeon's practice preference. Patients were included when they had a primary TAR in the timeframe noted and had a complete dataset up to at least the two-year data.

This cohort comprised 67 anterior and 48 lateral with balanced demographic for age (95%CI 63–67 yo) and gender (47% F). The lateral group had more complex cases with higher COFAS type arthritis. Comparing the two groups, a total of 40 reoperations (7 anterior, 33 lateral) occurred in 27 patients (5A, 22L). One patient had up to four related reoperations. The only revision was in the anterior group. The only soft tissue reconstruction was an STSG in the lateral group. Nine reoperations were irrigation debridement related to an infective process (3 A, 6L). The majority (19/33) of reoperations in the lateral group were gutter debridement (8) or lateral hardware removal (11). Operative time was not statistically different. The odds ratio of having a reoperation with a laterally based TAR was 6.19 compared to the anterior group.

This retrospective study outlines the intermediate results at two years of lateral and anterior total ankle replacements. This is a first study of this kind in the literature. This study did show that there were more reoperations after a laterally-based TAR than an anterior TAR, recognizing the significant case complexity imbalance between groups. This speaks to the relative increase resource utilization of laterally based TAR patients. Both implant designs carry different reoperation rates favoring the anterior group however larger prospective datasets will be needed with patient-reported outcome.


M. Ali C. DeSutter J. Morash M. Glazebrook

Anesthetic peripheral nerve blocks (PNB) have been shown to be more advantageous than general anesthesia in a variety of surgical operations. In comparison to conventional methods of general anesthesia, the choice of regional localized infiltration has been shown to shorten hospital stays, decrease hospital readmissions, allow early mobilization, and reduce narcotic use. Perioperative complications of PNBs have been reported at varying rates in literature. Thus, the purpose of this study was to provide a review on the clinical evidence of PNB complications associated with foot and ankle surgeries.

A systematic review of the literature was completed using PubMed search terms: “lower extremity”, “foot and ankle”, “nerve block”, and “complications”. All studies reporting minor and major complications were considered along with their acute management, treatments, and postoperative follow up timelines. The range of complications was reported for Sensory Abnormalities, Motor Deficits, Skin and systemic complications (local anesthetic systemic toxicity & intravascular injections). A designation of the scientific quality (Level I-IV) of all papers was assigned then a summary evidence grade was determined.

The search strategy extracted 378 studies of which 38 studies were included after criteria review. Block complications were reported in 20 studies while 18 studies had no complications to report. The quality of evidence reviewed ranged from Level I to Level IV studies with follow up ranging from twenty four hours to one-three year timelines. The range of complications for all studies reporting sensory abnormalities was 0.53 to 45.00%, motor deficits 0.05 to 16.22% and skin and systemic complications 0.05 to 6.67%. Sensory abnormalities that persisted at last follow up occurred in six studies with incidence ranging from 0.23 to 1.57%. Two studies reported motor complications of a foot drop with an incidence of 0.05% and 0.12%. When considering only the highest quality studies (Level 1) that had complications to report, the complications rate was 10.00% to 45.00% for sensory abnormalities, 7.81 to 16.22% for motor deficits, 6.67% for skin complications and 2.50% for systemic complications.

High quality studies (Level I providing Summary Grade A Evidence) reporting all complications with a range of incidence from 0 to 45%. While most of these complications were not serious and permanent, some were significant including sensory abnormalities, foot drop and CRPS. Based on this systematic review of the current literature, the authors emphasize a significant rate of complications with PNB and recommend that patients are appropriately informed prior to consenting to these procedures.


M. Wong C. Wiens S. Kooner R. Buckley P. Duffy R. Korley R. Martin D.W. Sanders B. Edwards P. Schneider

Nearly one quarter of ankle fractures have a recognized syndesmosis injury. An intact syndesmosis ligament complex stabilizes the distal tibio-fibular joint while allowing small, physiologic amounts of relative motion. When injured, malreduction of the syndesmosis has been found to be the most important independent factor that contributes to inferior functional outcomes. Despite this, significant variability in surgical treatment remains. This may be due to a poor understanding of normal dynamic syndesmosis motion and the resultant impact of static and dynamic fixation on post-injury syndesmosis kinematics. As the syndesmosis is a dynamic structure, conventional CT static images do not provide a complete picture of syndesmosis position, giving potentially misleading results. Dynamic CT technology has the ability to image joints in real time, as they are moved through a range-of-motion (ROM). The aim of this study was to determine if syndesmosis position changes significantly throughout ankle range of motion, thus warranting further investigation with dynamic CT.

This is an a priori planned subgroup analysis of a larger multicentre randomized clinical trial, in which patients with AO-OTA 44-C injuries were randomized to either Tightrope or screw fixation. Bilateral ankle CT scans were performed at 1 year post-injury, while patients moved from maximal dorsiflexion (DF) to maximal plantar flexion (PF). In the uninjured ankles, three measurements were taken at one cm proximal to the ankle joint line in maximal DF and maximal PF: Anterior (ASD), middle (MSD), and posterior (PSD) syndesmosis distance, in order to determine normal syndesmosis position. Paired samples t-tests compared measurements taken at maximal DF and maximal PF.

Twelve patients (eight male, six female) were included, with a mean age of 44 years (±13years). The mean maximal DF achieved was 1-degree (± 7-degrees), whereas the mean maximal PF was 47-degrees (± 8-degrees). The ASD in DF was 3.0mm (± 1.1mm) versus 1.9mm (± 0.8mm) in PF (p<0.01). The MSD in DF was 3.3mm (±1.1mm) versus 2.3mm (±0.9mm) in PF (p<0.01). The PSD in DF was 5.3mm (±1.5mm) versus 4.6mm (±1.9mm) in PF (p<0.01). These values are consistent with the range of normal parameters previously reported in the literature, however this is the first study to report the ankle position at which these measurements are acquired and that there is a significant change in syndesmosis measurements based on ankle position.

Normal syndesmosis position changes in uninjured ankles significantly throughout range of motion. This motion may contribute to the variation in normal anatomy previously reported and controversies surrounding quantifying anatomic reduction after injury, as the ankle position is not routinely standardized, but rather static measurements are taken at patient-selected ankle positions. Dynamic CT is a promising modality to quantify normal ankle kinematics, in order to better understand normal syndesmosis motion. This information will help optimize assessment of reduction methods and potentially improve patient outcomes. Future directions include side-to-side comparison using dynamic CT analysis in healthy volunteers.


M. Glazebrook J. Baumhauer A.S.E. Younger D. Fitch J. Quiton T. Daniels C. DiGiovanni

Autologous bone has been the gold standard for grafting material in foot and ankle arthrodesis. While autograft use has been effective, the harvest procedure does present risks to the patient including readmission, infection, and persistent graft harvest site pain. Previous studies have examined graft harvest site pain, but most have focused on the iliac crest and none have long term follow-up. The purpose of this study was to examine long-term (7–10 year) harvest site pain in subjects undergoing autograft harvest from multiple sites for hindfoot and/or ankle arthrodesis.

Sixty (60) subjects underwent hindfoot or ankle arthrodesis supplemented with autograft as part of the control arm of a prospective, randomized trial. The mean subject age was 59.4 years (range, 24.7–76.8) and mean body mass index was 30.6 kg/m2 (range, 22.0–44.0). There were 29 males and 31 female subjects. Subjects had the tibiotalar (37.9%), subtalar (24.1%), talonavicular (10.3%), subtalar/talonavicular (5.1%), or subtalar/calcaneocuboid/talonavicular (22.4%) joints arthrodesed. Autograft was harvested from either the proximal tibia (51.7%), iliac crest (17.2%), calcaneous (15.5%), distal tibia (6.8%), or other location (8.6%). Graft harvest site pain was evaluated using a 100-point visual analog score (VAS), with clinically significant pain being any score greater than 20.

Subjects were followed a mean of 9.0 years (range, 7.8–10.5). The percentage of subjects who reported clinically significant pain was 35.7%, 21.4%, 18.2%, 10.5%, 8.9%, and 5.2% at 2, 6, 12, 24, 52 weeks, and final follow-up (7.8–10.5 years), respectively. The mean VAS autograft harvest site pain at final follow-up was 4.4 (range, 0.0–97.0), with 37.9% of subjects reporting at least some pain. For three subjects (5%) with clinically significant pain (VAS >20) at final follow-up, two had proximal tibial harvest sites and one had an iliac crest harvest site. There was no correlation between graft volume and harvest site pain.

This study is the first to examine long-term pain following autologous bone graft harvest for hindfoot and/or ankle arthrodesis. Over a third of patients reported having some pain at an average follow-up of nine years, with 5% experiencing clinically significant pain. The results of this study suggest that harvesting autograft bone carries a risk of persistent, long-term pain regardless of the volume of graft that is harvested. This potential for persistent pain should be considered when informing patients of procedure risks and when deciding to use autograft or a bone graft substitute material.


S. Chambers C. Padmore S. Fan R. Grewal J.A. Johnson N. Suh

To determine the biomechanical effect of increasing scaphoid malunion and scaphoid non-union on carpal kinematics during dynamic wrist motion using an active wrist motion simulator.

Seven cadaveric upper extremities underwent active wrist flexion and extension in a custom motion wrist simulator with scaphoid kinematics being captured with respect to the distal radius. A three-stage protocol of progressive simulated malunion severity was performed (intact, 10° malunion, 20° malunion) with data analyzed from 45° wrist flexion to 45° wrist extension. Scaphoid malunions were modelled by creating successive volar wedge osteotomies and fixating the resultant scaphoid fragments with 0.062 Kirshner wires. At the completion of malunion motion trials, a scaphoid non-union trial was carried out by removing surgical fixation to observe motion differences from the malunion trials. Motion of the scaphoid, lunate, capitate, and trapezium-trapezoid was recorded and analyzed using active optical trackers.

Increasing scaphoid malunion severity did not significantly affect scaphoid or trapezium-trapezoid motion (p>0.05); however, it did significantly alter lunate motion (p<0.001). Increasing malunion severity resulted in progressive lunate extension across wrist motion (Intact – Mal 10: mean dif. = 7.1° ± 1.6, p<0.05; Intact – Mal 20: mean dif. = 10.2° ± 2.0, p<0.05;) although this change was not as great as the difference seen during non-union trials (native – non-union: mean dif. = 13.8° ± 3.7, p<0.05).

In this in-vitro model, increasing scaphoid malunion severity was associated with progressive extension of the lunate in all wrist positions. The clinical significance of this motion change is yet to be elucidated, but this model serves as a basis for understanding the kinematic consequences of scaphoid malunion deformities.


K. Au B. Gammon S. Undurraga K. Culliton H. Louati H. D'Sa

The clinical diagnosis of distal radioulnar joint (DRUJ) instability remains challenging. The current diagnostic gold standard is a dynamic computerized topography (CT) scan. This investigation compares the affected and normal wrists in multiple static positions of forearm rotation.. However, its accuracy has been questioned, as the wrist is unloaded and not placed under stress. This may fail to capture DRUJ instability that does not result in static malalignment between the ulnar head and sigmoid notch. The purpose of this biomechanical study was to evaluate the effectiveness of both dynamic and stress CT scans in detecting DRUJ instability.

A customized DRUJ arthrometer was designed that allows for both static positioning, as well as dorsal and volar loading at the DRUJ in various degrees of forearm rotation. Ten fresh frozen cadavers were prepared and mounted in the apparatus. CT scans were performed both in the unloaded condition (dynamic CT) and with each arm subjected to a standardized 50N volar and dorsal force (stress CT) in neutral and maximum pronation/ supination. The TFCC (triangular fibrocartilage complex)was then sectioned peripherally to simulate DRUJ instability and the methodology was repeated. CT scans were then evaluated for displacement using the radioulnar ratio method.

When calculating the radioulnar ratio for intact wrists using the dynamic CT technique, values were 0.50, 0.64, 0.34 for neutral, pronation and supination, respectively. When the TFCC was sectioned and protocol repeated, the values for the simulated unstable wrist for dynamic CT were 0.54, 0.62, 0.34 for neutral, pronation and supination, respectively. There was no statistically significant difference between the intact and sectioned states for any position of forearm rotation using dynamic CT. Usingstress CT, mean radioulnar ratios for the intact specimens were calculated to be 0.44, 0.36 and 0.31 for neutral, pronation and supination, respectively. After sectioning the TFCC, the radioulnar ratios increased to 0.61, 0.39 and 0.46 for neutral, pronation and supination. There was a statistically significant difference between intact and simulated-unstable wrists in supination (p = 0.002) and in neutral (p=0.003).

The radioulnar ratio values used to measure DRUJ translation for dynamic CT scans were unable to detect a statistically significant difference between stable and simulated unstable wrists. This was true for all positions of forearm rotation. However, when a standard load was placed across the DRUJ, statically significant changes in the radioulnar ratio were seen in neutral and supination between stable and simulated unstable wrists. This discrepancy challenges the current gold standard of dynamic CT in its ability to accurately diagnosis DRUJ instability. It also introduces stress CT as a possible solution for diagnosing DRUJ instability from peripheral TFCC lesions.


A. Kadar M. Haddara S. Fan S.J. Chinchalkar L. Ferreira N. Suh

Normal digital flexion relies on flexor tendon pulleys to transmit linear muscular force to angular digital motion. Despite the critical role these pulleys play, there is a growing trend among surgeons to partially sacrifice or “vent” them during flexor tendon repair to improve surgical exposure. Although this new practice is reported to improve outcomes after flexor tendon repair, there is concern for the long-term effects of bowstringing, reduced finger range of motion (ROM) and altered tendon biomechanics. The objective of this study was to examine the effects of the application of a thermoplastic ring, acting as an “external” pulley, on flexor tendon biomechanics and finger ROM. We hypothesized that the application of an external thermoplastic ring would produce a centripetal force over the tendon to reduce bowstringing, improve finger ROM, and restore tendon loads following pulley venting

Twelve digits comprised of the index, long, and ring fingers from four cadaveric specimens were tested using a novel in-vitro active finger motion simulator. Servo-motors were used to generate motion. Loads induced by flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP), and joint range of motion were measured with each sequential sectioning of the A2, A3, and A4 flexor pulley, in comparison to a native healthy finger condition. At each finger condition, A2 and A4 external thermoplastic pulley rings were applied over the proximal phalanx and middle phalanx, respectively, to recreate A2 and A4 function. Results were recorded and analyzed using a one way repeated-measures ANOVA.

Following venting of the A2, A3 and A4 pulley, proximal interphalangeal joint (PIPJ) ROM significantly decreased by 17.02 ± 8.42 degrees and distal interphalangeal joint (DIPJ) range of motion decreased by 17.25 ± 8.68 degrees compared to intact pulleys. Application of the external rings restored range of motion to within 8.14 ± 8.17 degrees at the PIPJ and to within 7.72 ± 8.95 degrees at the DIPJ. Similarly, pulley venting resulted in a 36% reduction in FDS load and 50% in FDP load compared to intact pulleys. Following application of the external rings, loads were almost restored to normal at 7% reduction for FDS load and 13% reduction for FDP load.

Venting of flexor tendon pulleys significantly alters flexor tendon biomechanics and digit range of motion. The application of thermoplastic rings acting as external pulleys over the proximal and middle phalanges is an effective, inexpensive, non-invasive and reproducible therapeutic method to restore flexor tendon biomechanics and digit range of motion.


C. Spencer A. Dawes B. McGinley K. Farley C. Daly M. Gottschalk E. Wagner

Thumb carpometacarpal (CMC) arthritis is a common and disabling condition that can be treated with an operative procedure. Before operative measures, patients typically undergo conservative treatment utilizing methods such as physical therapy and injections. This study aims to determine what clinical modalities are being used for preoperative evaluation and nonoperative therapy and the associated cost prior to operative intervention.

We queried Truven Market Scan, a large insurance provider database to identify patients undergoing CMC arthroplasty from 2010 to 2017. Patients were identified by common Current Procedural Terminology (CPT) codes for CMC arthroplasty. All associated CPT codes listed for each patient during the 1 year period prior to operative intervention were collected and filtered to only include those codes associated with the ICD-9/10 diagnosis codes relating to CMC arthritis. The codes were then categorized as office visits, x-ray, injections, physical therapy, medical devices, and preoperative labs. The frequency and associated cost for each category was determined.

There were 44,676 patients who underwent CMC arthroplasty during the study period. A total of $26,319,848.36 was charged during the preoperative period, for an average of $589.13 per patient. The highest contributing category to overall cost was office visits (42.1%), followed by injections (13.5%), and then physical therapy (11.1%). The most common diagnostic modality was x-ray, which was performed in 74.7% of patients and made up 11.0% of total charges. Only 49% of patients received at least one injection during the preoperative period and the average number of injections per patient was 1.72. Patients who were employed full time were more likely to receive two or more injections prior to surgery compared to patients who had retired (47% of full-time workers; 34% of retirees).

The modalities used for the preoperative evaluation and conservative treatment of CMC arthritis and the associated cost are important to understand in order to determine the most successful and cost-effective treatment plan for patients. Surprisingly, despite the established evidence supporting clinical benefits, many patients do not undergo corticosteroid injections. With office visits being the largest contributor to overall costs, further inquiry into the necessity of multiple visits and efforts to combine visits, can help to reduce cost. Also, with the advent of telemedicine it may be possible to reduce visit cost by utilizing virtual medicine. Determining the best use of telemedicine and its effectiveness are areas for future investigation.


T.V. Stephens T.J. Goetz Z. Glaris

Ulnocarpal impaction (UCI) is a common cause of ulnar-sided wrist pain. UCI typically occurs in wrists with positive ulnar variance, which causes altered loading mechanics between the ulnar head, lunate and triquetrum. However, many individuals with positive ulnar variance never develop UCI, and some with neutral or negative ulnar variance do experience UCI. This suggests that other variables contribute to the development of UCI. Suspected culprits include lunate morphology, and dynamic changes with loaded (grip) pronation. If these anatomic variations are contributing to UCI, we expect them to influence functional impairment scores. Therefore, the objective of this study was to evaluate the relationship between radiographic parameters and pre-surgical upper extremity patient-rated outcomes scores (PROS) in patients with a diagnosis of UCI.

Retrospective cohort study of patients undergoing ulnar shortening osteotomy or arthroscopic wafer procedure for UCI. Data derived from prospectively collected departmental database that captured demographic, clinical, functional and radiographic information. Radiographic parameters evaluated were: lunate morphology [presence vs. absence of hamate facet; Antuna-Zapico (A-Z) classification], and dynamic changes on grip view [difference in lunate-ulnar head distance (LUD); difference in lunate uncovering index (LUI)]. PROS assessed were QuickDASH and Patient-Rated Wrist Evaluation (PRWE) scores, collected at patient enrolment. ANOVA was used to assess for differences in PROS between A-Z classification groups. Student's t-test was used to assess for differences in PROS based on presence/absence of a hamate facet. Regression analysis evaluated a relationship between change in LUD with grip and PROS, and change in LUI with grip and PROS.

Preliminary analysis included 23 wrists, with a mean patient age of 48.9 years [standard deviation (SD) 14.5 years]. Forty-eight percent were male, and the dominant limb was involved in 52.2% of cases. Average QuickDASH and PRWE scores at enrolment were 50.9 (SD 22.2) and 62.2 (SD 22.0), respectively. Assessment of radiographs revealed 17 patients (73.9%) without a hamate facet. Five patients (21.7%) had A-Z Type I lunate morphology, and nine (39.1%) had Type II and Type III morphology, respectively. ANOVA revealed no differences in enrolment QuickDASH (p = 0.185) or PRWE (p = 0.256) scores between A-Z classification groups. Similarly, Student's t-test found no difference based on presence/absence of a hamate facet (QuickDASH p = 0.594; PRWE p = 0.573). Regression analysis revealed no relationship between change in LUD with grip and PROS (QuickDash R2 = 0.020, p = 0.619; PRWE R2 = 0.009, p = 0.733), and no relationship between change in LUI with grip and PROS (QuickDash R2 = 0.000, p = 0.913; PRWE R2 = 0.010, p = 0.722).

Preliminary results suggest no relationship between A-Z classification lunate morphology, presence/absence of a hamate facet, change in LUD, or change in LUI and pre-surgical PROS. It is unclear if our findings represent the true relationship between these radiographic parameters and PROS, or reflect our preliminary sample size. Data analysis is ongoing to add clarity to this question.


B.H. Perey K. Chung H. Kim S. Malay M. Shauver

To compare 24-month patient-reported outcomes after surgical treatment or casting in patients age 60 years of age or older with unstable distal radius fractures (DRF's).

The Wrist and Radius Injury Surgical Trial (WRIST), is the largest randomized, multicenter trial in Hand Surgery, which enrolled 304 adults with isolated, unstable DRF's at 24 institutions. WRIST participants were followed for 24 months- longest follow-up among prospective studies comparing four treatment methods. Patients who agreed to surgical treatment (n=187) were randomized to internal fixation with volar plate (VLPS), external fixation, or percutaneous pinning; patients who preferred conservative management (n=117) received casting. The primary outcome was 24-month Michigan Hand Outcomes Questionnaire (MHQ) Summary score. Secondary outcomes were MHQ Domain scores.

At 24-month assessment, participants' mean MHQ Summary score was 86 (95% CI: 83,88), representing good hand function. Participants reported good return of their Activities of Daily Living (ADLs) with a mean MHQ ADL score of 88 (95% CI: 85,91). Finally, participants were satisfied, with a mean MHQ Satisfaction score of 84 (95% CI: 80,88). There were no significant differences in score by treatment group in any MHQ domain at 24 months. Six weeks after surgery, VLPS participants scored significantly higher than the other three groups on (ADLs) and Satisfaction (both p<0.0001), whereas participants who received external fixation scored significantly lower than the casting and VLPS groups on the same domains. By the 3-month assessment, the gap between VLPS and casting had disappeared but external fixation participants continued to report significantly worse scores. External fixation participants did not report comparable ADL scores to the other three groups until 12 months after surgery.

Participants reported good outcomes 24 months after DRF regardless of treatment. Casting and VLPS are both acceptable treatments for older adults. The decision between the two treatments should be made considering patient goals regarding recovery speed and desire to avoid surgical risks. External fixation should be avoided because of worse outcomes in the year after surgery and the risk of pin site infections.


A. Mazor Z. Glaris T.J. Goetz

Thumb Carpometacarpal (CMC) arthritis is a common pathology of the hand. Surgical treatment with thumb reconstruction is well described. Retrospective outcomes have been described for multiple techniques, suggesting patient satisfaction with multiple different techniques. The Thompson technique uses a slip of Abductor Pollicis Longus for suspension and interposition as well as excision of the trapezium. Retrospective outcomes suggest good patient satisfaction. We describe the improvement in Patient rated outcomes scores (PROS) and changes in pinch and grip strength in a prospectively collected cohort of patients treated with a modification of the Thompson technique.

To assess changes in Patient-Rated Wrist Evaluation (PRWE) and Disabilities of the Arm, Shoulder, and Hand (QDASH) scores, as well as to determine the percentage of patients that surpassed the Minimal Clinically Important Difference (MCID) figure that has been described in the literature for these tests. In addition, measurements for evaluation of pinch and grip strength prior to surgery, at six, and at twelve months follow-up were done.

Between June 2016 and February 2019, a consecutive prospective series of Thirty-seven LRTI procedures with APL suspension arthroplasty (Thompson technique) were performed on 34 patients with osteoarthritis of the thumb CMC joint (24 women / 13 men; age 63±8.553). All surgeries were performed by the senior surgeon. Data was collected as part of a wrist pain database. Patients failing conservative treatment and electing surgical management of thumb arthritis were enrolled into the database. Patients were evaluated pre-operatively with the PRWE and QDASH questionnaires and grip and pinch strength measurements, and postoperatively at 6 and 12 months. The MCID for QDASH and PRWE is 14 and will be evaluated at the same time points for each patient. Paired student T-test was used to determine differences in the means. Data are presented as mean ± SD unless stated otherwise. Differences with p<.05 were considered significant.

Compared to the pre-operative assessment, at six months, the means of PRWE pain score and PRWE functional score decreased significantly (32.824 SD±10.721 vs. 19.265 SD±12.268 and 30.262 SD±10.050 vs. 16.431 SD± 9.697 respectively, n=34,, p<0.05). 69% of the patients surpassed the MCID of 14 six months after the surgery. In addition, QDASH mean score also dropped from 56.108 to 32.219 (SD± 21.375 n=32. p<0.05) at six months. At one year, 76% of the patients were above the MCID of 14. The mean scores of these three questionnaires did not show significant change between six and twelve months. Compared to the initial pre-operative assessment, we found no statistically significant difference in the means of grip strength, point pinch, and lateral key pinch at six and twelve months.

Thumb reconstruction with APL suspension arthroplasty demonstrates significant improvement in pain and functionality. No significant improvement in grip and pinch strength is observed, even at one year postoperatively.


S. McLaren D. Sauder L. Sims R. Khan Y. Cheng

Outcomes following carpal tunnel release are generally favorable. Understanding factors that contribute to inferior outcomes may allow for strategies targeted at improving results in these patients. Our purpose was to determine if patients' underlying personality traits, specifically resiliency and catastrophization, impact their post-operative outcomes following carpal tunnel release.

A prospective case series was performed. Based on our power analysis, 102 patients were recruited. Patients completed written consent, the Boston Carpal Tunnel Questionnaire (BCTQ), the Pain Catastrophizing Scale (PCS) and the Brief Resiliency Scale (BRS). A single surgeon, or his resident under supervision, then performed an open carpal release under local anaesthetic. Our primary outcome measure was a repeat BCTQ at three- and six-months. Univariate and multivariate analysis was performed to assess the correlation between PCS and BRS scores and final BCTQ scores.

Forty-three and sixty-three participants completed the BCTQ at three and six months respectively. All patients showed improvement in their symptoms (p = 0.001). There was no correlation between patients PCS or BRS and the amount of improvement. There was also no correlation between PCS or BRS and the patients' raw scores at baseline or follow-up.

Patients self-assessed resiliency and degree of pain catastrophization has no correlation with the amount of improvement they have three or six months post-operatively. Most patients improved following carpal tunnel release, and patients with low resiliency and high levels of pain catastrophization should expect comparable outcomes to patients without these features.


M. Gottschalk A. Dawes K. Farley E. Nazzal C. Campbell C. Spencer C. Daly E. Wagner

Perioperative glucocorticoids have been used as a successful non-opioid analgesic adjunct for various orthopaedic procedures. Here we describe an ongoing randomized control trial assessing the efficacy of a post-operative methylprednisolone taper course on immediate post-operative pain and function following surgical distal radius fixation. We hypothesize that a post-operative methylprednisolone taper course following distal radius fracture fixation will lead to improved patient pain and function.

This study is a randomized control trial (NCT03661645) of a group of patients treated surgically for distal radius fractures. Patients were randomly assigned at the time of surgery to receive intraoperative dexamethasone only or intraoperative dexamethasone followed by a 6-day oral methylprednisolone (Medrol) taper course. All patients received the same standardized perioperative pain management protocol. A pain journal was used to record visual analog pain scores (VAS-pain), VAS-nausea, and number of opioid tablets consumed during the first 7 post-operative days (POD). Patients were seen at 2-weeks, 6-weeks, and 12-weeks post-operatively for clinical evaluation and collection of patient reported outcomes (Disabilities of the Arm, Shoulder and Hand Score [qDASH]). Differences in categorical variables were assessed with χ2 or Fischer's exact tests. T-tests or Mann-Whitney-U tests were used to compare continuous data.

Forty-three patients were enrolled from October 2018 to October 2019. 20 patients have been assigned to the control group and 23 patients have been assigned to the treatment group. There were no differences in age (p=0.7259), Body Mass Index (p=0.361), race (p=0.5605), smoking status (p=0.0844), or pre-operative narcotic use (p=0.2276) between cohorts. 83.7% (n=36) of patients were female and the median age was 56.9 years. No differences were seen in pre-operative qDASH (p=0.2359) or pre-operative PRWE (p=0.2329) between groups. In the 7 days following surgery, patients in the control group took an average of 16.3 (±12.02) opioid tablets, while those in the treatment group took an average of 8.71 (±7.61) tablets (p=0.0270). We see that significant difference in Opioid consumption is formed at postoperative day two between the two groups with patients in the control group taking. Patient pain scores decreased uniformly in both groups to post-operative day 7. Patient pain was not statistically from POD0 to POD2 (p=0.0662 to 0.2923). However, from POD4 to POD7 patients receiving the methylprednisolone taper course reported decreased pain (p=0.0021 to 0.0497). There was no difference in qDASH score improvement at 6 or 12 weeks. Additionally, no differences were seen for wrist motion improvement at 6 or 12 weeks.

A methylprednisolone taper course shows promise in reducing acute pain in the immediate post-operative period following distal radius fixation. Furthermore, although no statistically significant reductions in post-operative opioid utilization were noted, current trends may become statistically significant as the study continues. No improvements were seen in wrist motion or qDASH and continued enrollment of patients in this clinical trial will further elucidate the role of methylprednisolone for these outcomes.


R. El-Hawary K. Logan B. Orlik L. Gauthier M. Drake K. Reid L. Parafianowicz E. Schurman S. Saunders L. Larocque K. Taylor

The purpose of this study was to measure the effect of the implementation of a LEAN continuous process improvement initiative on the waitlist in an ambulatory pediatric orthopaedic clinic.

LEAN is a set of principles that guide organizational thinking and form a comprehensive approach to continuous process improvement. In 2016, our health centre began its journey towards becoming a LEAN organization. The health centre's Strategy and Performance portfolio collaborated with the Orthopaedic Clinic Team to facilitate a Value Stream Analysis, which mapped the clinic process from referral to discharge from care. This informed the plan for targeted improvement events designed to identify and reduce non-value added activity, while partnering with patients and families to share their experiences with care in the clinic. Improvement events included: In-Clinic Patient Flow; Scheduling Process Review; Standardized Triage Process; Clinician Schedule; 5-S Large Cast and Sample Exam Rooms; Booking Orthopedics Clinic; and Travelling and Remote Care. During each event, solutions were identified to improve the patient experience, access, and clinic flow. These solutions have been standardized, documented, and continuously monitored to identify additional improvement opportunities. Comparison of wait-list and percentage of new patients seen within target window was performed from August 2017 to December 2018.

The LEAN initiative resulted in a 48% decrease in wait-list for new patients, which translated to an improvement from 39% to 70% of new patients seen within their target window. There was a 19% decrease in the 3400+ patient wait-list for follow-up appointments, an 85% reduction in follow-up patients waiting past their target date for an appointment, and the number of patients waiting over a year beyond their target appointment improved from over 300 patients to 0 patients. There was a 15% improvement in average length of clinic visit.

Without the addition of new resources, the implementation of a LEAN continuous process improvement initiative improved the waitlist for new patients in an ambulatory pediatric orthopaedic clinic by almost 50%. Solutions identified and implemented through the LEAN process have contributed to unprecedented improvements in access to care. In fulfilling one of the LEAN theory principles to “pursue perfection”, the paediatric orthopaedic clinic team has embraced a culture of continuous improvement and continues to use LEAN tools such as daily huddles and visual management to monitor solutions and identify gaps.


S. Kelley C. Maddock C. Bradley M. Gargan O. Safir

The use of total hip arthroplasty in adolescents for end-stage degenerative hip disease is controversial with few reported outcomes in the literature. The purpose of the study was to report the outcomes of total hip arthroplasty in a cohort of adolescents managed by a multidisciplinary team of paediatric and adult orthopaedic surgeons from a single centre.

A multidisciplinary clinic consisting of paediatric and adult hip surgeons was established in 2013 to identify, treat and prospectively follow adolescents who would potentially beneift from a total hip arthoplasty. To date 29 consecutive adolescent patients (20 female, 9 male, 32 hips) with end stage degenerative hip disease have undergone cementless primary total hip arthroplasty. Mean age at decision to treat was 15.7 years (age 11.4–18.5). Ten different underlying paediatric specific pathologies were documented including DDH, cerebral palsy, JIA, skeletal dysplasias, SCFE and idiopathic chondrolysis. Three patients had bilateral staged procedures. Clinical baseline and outcomes were measured using Oxford Hip Score (OHS), WOMAC score and ASKp scores. Radiographic follow-up was conducted at 6 weeks, 6 months and yearly thereafter. Post-operative complications were recorded.

Twenty-five hips were eligible for minimum 2-year follow-up scoring at a mean 2.7 years (2.0–3.6 years). No intraoperative complications occurred. One case of recalcitrant postoperative psoas tendonitis occured. OHS improved from 25 (7–43) to 41 (23–48). WOMAC improved from 48 (12–8) to 12 (1–44), and ASKp improved from 78% (33–98%) to 93% (73–100%). Radiographic review revealed acceptable alignment of all components with no signs of loosening or wear. No revision of components was required. One patient died at 6 months post op from an unrelated condition.

The early term results of total hip arthroplasty in adolescents from our multidisciplinary program are encouraging. Improvements in quality of life to normal values were seen as were hip scores consistent with satisfactory joint function. Depite the range of complex and varied causes of arthritis seen in this population the establishment of combined paediatric and adult orthopaedic surgical teams appears to be a successful model to manage end-stage degenerative hip disease in adolescents.


Z. DeVries N. Barrowman K. Smit A. Tice D. Mervitz J. Jarvis

Rapid discharge pathways (RDP) have been implemented throughout most areas of orthopaedics. The primary goal of these pathways is to standardize the post-surgical hospital course for patients in order to decrease hospital length-of-stay (LOS). Surgical treatment of adolescent idiopathic scoliosis (AIS) remains one of the most invasive pediatric orthopaedic procedure and is routinely associated with a prolonged hospital stay. The implementation of RDPs following surgery for AIS has shown to be successful; however, all of these studies have been conducted within the United States and it has been shown previously that there exists major differences in hospital LOS and in post-operative complications between Canada and the United States. Therefore, the objective of this study was to determine if the implementation of a RDP at a single children's tertiary-referral centre in Canada could decrease hospital LOS without increasing post-operative complications.

A retrospective chart review was completed for all patients who underwent posterior spinal instrumentation and fusion (PSIF) between March 1st, 2010 and February 28th, 2019, with date of implementation being March 1st, 2015. Patient pre-operative, operative, and post-operative information was collected from the charts along with the primary outcome variables: LOS, wound complication, 30-day return to the OR, 30-day emergency department admission, and 30-day hospital readmission. An interrupted time series analysis with a robust linear regression model was utilized to assess for any differences in outcomes following implementation of the RDP. Ninety days before and after the implementation of the RDP was not included in this analysis due to variances in practice that were occurring at this time.

A total of 244 participants were identified, with 113 patients in the conventional pathway and 131 patients in the RDP cohort. No significant differences in pre-operative or operative characteristics existed between the groups, except for the RDP group having approximately a 50 larger pre-operative curve and the conventional pathway having on average 200mL greater intra-operative blood loss (p<0.05). Hospital LOS was found to be significantly shorter in the RDP group, with the median LOS being 5.2 [95% IQR 4.3–6.1] days in the conventional group and 3.4 [95% IQR 3.3–3.5] days in the RDP group (p<0.05). Patients in the RDP group were also found to stand 0.9 days earlier, walk 1.1 days earlier, their Foley catheter was discontinued 0.5 days earlier and their personal controlled analgesia was discontinued 12 hours sooner (p<0.05). There were no differences in post-operative complications between the two groups (p>0.05).

This study demonstrates that implementing a RDP following PSIF for AIS can successfully decrease hospital LOS without increasing post-operative complications in a single payer universal healthcare system. The associated decrease in LOS could correlate with decreasing costs for both the healthcare system and for the patient's family.


P. Sidhu J. Smith H. Chhina J. Abad B. Lim I. Pike A. Cooper

Supracondylar fractures of the humerus (SCH) are the most common fractures sustained following a fall on an outstretched hand in healthy children, and one of the leading causes of hospital admission and surgical intervention. With increasing severity of injury, treatment options become more invasive and the potential for long lasting complications increases. The aim of this study is to examine the causes and circumstances surrounding SCH in public play spaces particularly to determine whether or not the playground equipment implicated in injurious falls is compliant with Canadian Standards Association (CSA) standards.

Children aged 6–12 years who sustained SCH while playing at a public play space between 2017 and 2019 were recruited from the paediatric orthopaedic clinic. Public playgrounds within a 50 km radius of the clinic were visited by research assistants. Using GPS coordinates from photographs taken by the children at the site of injury or play structures identified by the children using Google Maps, play structure type, dimensions, height of fall, and the type and depth of the surface material were collected from each site and compared to the relevant CSA standard.

Of the 89 SCH injuries reported during the recruitment period, 49 (55%) occurred on public play structures. Thirty-nine injury sites, representing 42 SCH cases, were accessible to conduct site visits and were included in the analysis. Thirteen children (31%) sustained Type One, 19 (45%) were Type Two, and 10 (24%) were Type Three SCHs. The mean child age at injury was 7.13 years. Of the 42 SCH cases, 37 sites had woodchips surfacing (88%); three had rubber (7%), one had cement (2%), and one had sand (2%). Of the 36 sites where woodchip depth measurements could be obtained, only seven (19%) met the minimum CSA depth. Out of the 42 SCH cases, 29 injuries (69%) involved upper body equipment (i.e. monkey bars or similar) and track rides. Fourteen of these 29 injuries (48%) occurred on structures that did not meet CSA standards for fall height. All rotating play structures had less than half of the required clearance between the components.

Eighty-six percent of SCH cases occurred in playgrounds where at least one of the required CSA standards was not met. Woodchip surfacing was of particular concern because 81% of woodchip surface depths failed to meet CSA standards. Of the 14 injuries where fall height did not meet CSA standards, 11 (79%) also did not meet minimum CSA surface depth. Field investigation into the characteristics of playgrounds in which children sustain SCH can guide preventative policy and practice measures. Municipalities and school boards should be alerted to the need for regular maintenance of woodchip playground surfacing, in order to remain compliant with the minimum surface depth and prevent serious injuries. Additionally, compliance with minimum surface depths can also decrease fall heights to meet CSA standards. By minimizing the prevalence of SCH injuries occurring on play structures and the need for emergency department visits, the burden to healthcare systems and families of injured children can potentially be reduced.


B. Shore D. Cook J. Hill A. Riccio J. Murphy K. Baldwin

Septic Arthritis (SA) is considered a surgical urgency/ emergency by physicians around the world. As our understanding grows, and improved diagnostic algorithms are developed, it has become apparent that competing interests in terms of accurately diagnosing concurrent osteomyelitis may supercede rapid surgical intervention when the imaging is timely. Nevertheless, even in cases of isolated SA, many patients will require repeat surgery. We aimed to assess factors which could predict this.

A multicenter retrospective redcap database was created involving 20 pediatric centers from the CORTICES study group with the goal of better understanding pediatric musculoskeletal infection (PMSKI). All patients who met inclusion for the database were considered, surgeons for each site determined through imaging and chart review which patients met the diagnosis of isolated SA. Patients with concomitant abscesses or osteomyelitis were expressly excluded. Appropriate non parametric statistics were used to assess univariate significance. Multivariable logistic regression was used to assess clinical factors associated with an increased likelihood of more than one surgery. Receiver characteristics operating curve (ROC) analysis was used to determine optimal cutoffs to discriminate between children who required more than one surgery compared to those who required only one surgery. A probability algorithm was developed for the number of clinical factors present and the likelihood requiring more than one surgery following SA diagnosis.

“Four hundred and fifty-four patients with isolated SA were analyzed from 20 US hospitals. Patients were 5.4 +/− 4.8 years old at admission, and the cohort was 56% male. Of the 454 patients, 47 (10.4%) needed more than one surgery. Bivariate comparisons across surgery groups found significant differences in minimum platelet count (pplatelet, a patient has a 0.3% reduction in the odds of needing more than one surgery (OR=.997; p=0.04). For each additional ten units of CRP, a patient has a 0.1% increase in the odds of needing more than one surgery (OR=1.001; p<0.001). Our predictive algorithm found that children with both risk factors had a 64% chance of requiring multiple surgeries.

Higher CRP values and lower platelet values indicate more severe disease in isolated SA with a greater likelihood of repeat surgery. Higher CRP and lower platelet counts may portend multiple surgeries and caregivers of children with isolated SA should be advised as such.


R. Pathy B. Liquori G. Gorton M. Gannotti

To assess long and short term kinematic gait outcomes after rectus femoris transfers (RFT) in ambulatory children with cerebral palsy (CP).

A retrospective review was conducted of ambulatory children with spastic diplegic CP, who had RFT plus motion analysis preoperatively and 1 year post-operatively. Those with 5 and 10 year post-operative motion analysis were also included. The primary variables were: peak knee flexion range of motion in swing (PKFSW), timing of peak knee flexion in swing as a percent of the gait cycle (PKF%GC), and knee range of motion from peak to terminal swing (KROM). Responders and non-responders were identified. Descriptive, kinematic and kinetic variables were evaluated as predictors of response.

119 ambulatory children (237 limbs) with spastic diplegic CP who had RFT were included. Mean age at surgery was 10.2 years (range 5.5 to 17.5). Sixty-seven participants were classified at GMFCS Level II and 52 at GMFCS Level III. All participants (237 limbs) had a preoperative and 1 year postoperative motion analysis. Motion analysis at 5 and 10 years post-operatively included 82 limbs and 28 limbs, respectively. Ninety-three (39%) limbs improved in both PKFSW and PKF%GC. PKFSW improved in 59% of limbs. Responders started 1.2 SD below the mean PKFSW preoperatively, and improved by an average of 1.9 SD to reach a normal range at 1 year post-operatively (p < 0.05). Improvement was maintained at 5 and 10 years postoperatively. Those at GMFCS level II were more likely [OR 1.71, CI 1.02, 2.89] to have improved PKFSW at 1 year postoperatively than those at GMFCS level III. PKF%GC improved in 70% of limbs. Responders had delayed PKF%GC, starting 10 SD above the mean (later in the gait cycle) preoperatively. Their timing improved towards normal values: 5 SD, 5.9 SD, 3.5 SD from the mean, (earlier in the gait cycle) at 1, 5 and 10 years postoperatively, respectively (p<0.05). KROM improved in only 24% of limbs. For all variables, there was a significant difference in mean preoperative values between responders and non-responders (p<0.05).

RFT improves short and long-term kinematic gait outcomes. The majority of children responded to RFT with improvements in PKFSW or PKF%GC at 1, 5, and 10 years post RFT. GMFCS level is a predictor of improved PKFSW, with children at GMFCS Level II having an increased likelihood of improvement at 1 year post surgery. Children who have worse preoperative values of PKFSW, PKF%GC, and KROM have a greater potential for benefit from RFT. Characteristics associated with responders who maintain long term positive outcomes need to be identified.


R. El-Hawary K. Padhye J. Howard J. Ouellet N. Saran E.P. Abraham N. Manson D.C. Peterson P.C. Missiuna D. Hedden Y. Alkhalife V. Viswanathan D.L. Parsons F. Ferri-de-Barros J. Jarvis P. Moroz S. Parent J. Mac-Thiong J. Hurry B. Orlik K. Bailey J. Chorney

Proximal junctional kyphosis (PJK) is defined as adjacent segment kyphosis >10° between the upper instrumented vertebrae and the vertebrae 2 levels above following scoliosis surgery. There are few studies investigating the predictors and clinical sequelae involved with this relatively common complication. Our purpose was to determine the radiographic predictors of post-op PJK and to examine the association between PJK and pain/HRQOL following surgery for AIS.

The Post-Operative Recovery after Scoliosis Correction: Home Experience (PORSCHE) study was a prospective multicenter cohort of AIS patients undergoing spinal fusion surgery. Pre-op and minimum 2 year f/u scoliosis and sagittal spinopelvic parameters (thoracic kyphosis–TK, lordosis–LL, pelvic tilt-PT, sacral slope-SS, pelvic incidence-PI) were measured and compared to numeric rating scale for pain (NRS) score, SRS-30 HRQOL and to the presence or absence of PJK (proximal junctional angle >100). Continuous and categorical variables were assessed using logistic regression and binomial variables were compared to binomial outcomes using chi-square.

163 (137 females) patients from 8 Canadian centers met inclusion criteria. At final f/u, PJK was present in 27 patients (17%). Pre-op means for PJK vs No PJK: Age 14.1 vs 14.7yr; females 85 vs 86%; scoliosis 57±22 vs 62±15deg; TK 28±18 vs 19±16deg ∗, LL 62±11 vs 60±12deg, PT 8±12 vs 10±10deg, SS 39±8 vs 41±9deg, PI 47±14 vs 52±13deg, SVA −9±30 vs −7±31mm. Final f/u for PJK vs No PJK: Scoliosis 20±11 vs 18±8deg, final TK 26±12 vs 19±10deg∗, LL 60±11 vs 57±12deg, PT 9±12 vs 12±13deg, SS 39±9 vs 41±9deg, PI 48±17 vs 52±14deg, SVA −23±26 vs −9±32mm∗. Significant findings: Pre-op kyphosis >40deg has an odds ratio (OR) of 4.41 (1.50–12.92) for developing PJK∗. The presence of PJK was not associated with any significant differences in NRS or SRS-30. ∗denotes p<0.05.

This prospective multicenter cohort of AIS patients demonstrated a 17% risk of developing PJK. Pre-op thoracic kyphosis >40deg was associated with the development of PJK; however, the presence of PJK was not associated with increased pain or decreased HRQOL.


S. Miller M. O'Donnell K. Mulpuri

Treatment for hip displacement in children and youth with cerebral palsy (CP) is dependent upon when the problem is detected. Hip surveillance aims to identify hip displacement early through systematic screening and, together with timely orthopaedic intervention, can eliminate the need for salvage hip procedures. Here we report the impact on surgical practice of 1) hip surveillance program advocacy and knowledge translation efforts and 2) initial population-based program implementation.

A retrospective review was completed of all children with CP undergoing surgery for hip displacement at a provincial tertiary pediatric hospital in the years 2004 to 2018. Date and type of surgery, age at surgery, Gross Motor Function Classification System (GMFCS) level, and pre-operative migration percentages (MP) were collected. Surgeries were categorized as soft-tissue release, reconstructive, and salvage procedures. Results were collected for three time periods: historical (September 2004- June 2010), hip surveillance advocacy and knowledge translation (July 2010- August 2015), and post provincial hip surveillance program implementation (September 2015 – December 2018).

A total of 261 surgeries on 321 hips were reviewed. The rate of salvage procedures dropped from 29% (24) of surgeries performed in the historical period to 12% (14) during the period that included targeted hip surveillance knowledge translation and development of provincial guidelines. Since implementation of the surveillance program, salvage procedures have accounted for 7% (4) of interventions performed; all of these were in patients new to the province or existing patients. During the three study periods, reconstructive surgeries accounted for 64%, 81%, and 80% of the interventions performed. The mean initial MP at time of reconstructive surgery has decreased from 66% (SD 20%) in the historical time period to 57% (SD 25%) and 57% (SD 22%) in the subsequent time periods. There were a greater number of children at GMFCS levels III and IV in the two more recent time periods suggesting surveillance may assist in identifying children at these levels of impairment. The rate of soft-tissue surgeries was low during all time periods with the number trending higher since program implementation (7%, 7%, 10%).

Knowledge translation and use of standardized surveillance guidelines can have a significant impact on the prevalence of salvage hip surgeries. Centers should utilize existing surveillance guidelines and educate key stakeholders about the importance of hip surveillance in the absence of a formal hip surveillance program.


M. Gerges H. Eng H. Chhina A. Cooper

Bone age is a radiographical assessment used in pediatric medicine due to its relative objectivity in determining biological maturity compared to chronological age and size.1 Currently, Greulich and Pyle (GP) is one of the most common methods used to determine bone age from hand radiographs.2–4 In recent years, new methods were developed to increase the efficiency in bone age analysis like the shorthand bone age (SBA) and the automated artificial intelligence algorithms. The purpose of this study is to evaluate the accuracy and reliability of these two methods and examine if the reduction in analysis time compromises their accuracy.

Two hundred thirteen males and 213 females were selected. Each participant had their bone age determined by two separate raters using the GP (M1) and SBA methods (M2). Three weeks later, the two raters repeated the analysis of the radiographs. The raters timed themselves using an online stopwatch while analyzing the radiograph on a computer screen. De-identified radiographs were securely uploaded to an automated algorithm developed by a group of radiologists in Toronto. The gold standard was determined to be the radiology report attached to each radiograph, written by experienced radiologists using GP (M1). For intra-rater variability, intraclass correlation analysis between trial 1 (T1) and trial 2 (T2) for each rater and method was performed. For inter-rater variability, intraclass correlation was performed between rater 1 (R1) and rater 2 (R2) for each method and trial.

Intraclass correlation between each method and the gold standard fell within the 0.8–0.9 range, highlighting significant agreement. Most of the comparisons showed a statistically significant difference between the two new methods and the gold standard; however it may not be clinically significant as it ranges between 0.25–0.5 years. A bone age is considered clinically abnormal if it falls outside 2 standard deviations of the chronological age; standard deviations are calculated and provided in GP atlas.6–8 For a 10-year old female, 2 standard deviations constitute 21.6 months which far outweighs the difference reported here between SBA, automated algorithm and the gold standard. The median time for completion using the GP method was 21.83 seconds for rater 1 and 9.30 seconds for rater 2. In comparison, SBA required a median time of 7 seconds for rater 1 and 5 seconds for rater 2. The automated method had no time restraint as bone age was determined immediately upon radiograph upload. The correlation between the two trials in each method and rater (i.e. R1M1T1 vs R1M1T2) was excellent (κ= 0.9–1) confirming the reliability of the two new methods. Similarly, the correlation between the two raters in each method and trial (i.e. R1M1T1 vs R2M1T1) fell within the 0.9–1 range. This indicates a limited variability between raters who may use these two methods.

The shorthand bone age method and an artificial intelligence automated algorithm produced values that are in agreement with the gold standard Greulich and Pyle, while reducing analysis time and maintaining a high inter-rater and intra-rater reliability.


M.M.G. Sun N. Buckler M. AlNouri M. Vaughan T. St. Hilaire P. Sponseller J. Smith G. Thompson J. Howard R. El-Hawary

Scoliosis is estimated to occur between 21–64% of patients with cerebral palsy (CP), where a subset of patients develops early onset scoliosis (EOS) before the age of ten. Traditional growth friendly (TGF) surgeries in the context of traditional growing rods have been shown to be effective in treating scoliosis in this population, however significant complication rates are reported. Currently, no studies have been done to examine the effect of novel growth friendly surgeries such as magnetically controlled growing rods (MCGR) on EOS in CP patients. The objective of this study is to compare MCGR with TGF surgeries in this patient population, specifically by evaluating radiographic measurements and risk of unplanned reoperations (UPRORs).

Patients with EOS secondary to CP were prospectively identified from an international database, with data retrospectively analyzed. Scoliosis (primary curve), maximum kyphosis, T1-S1 and T1-T12 height were measured pre-operation, immediate post-operation, and at two-years follow-up. The risk and etiology of UPRORs were compared between MCGR and TGF. P < 0.05 was considered statistically significant for all analyses.

Of the 120 patients that met inclusion criteria, 86 received TGF (age 7.5 ± 1.8 years; follow-up 7.0 ± 2.9 years) and 34 received MCGR (age 7.1 ± 2.2 years, follow-up 2.8 ± 0.5 years). Compared to TGF, MCGR resulted in significant improvements in maintenance of scoliosis correction (p=0.04). At final follow-up, UPRORs were 24% for MCGR (8/34 patients) and 43% (37/86 patients) for TGF (p=0.05). To minimize the influence of follow-up period, UPRORs within the first two years post-operation were evaluated: MCGR (21%, 7/34 patients) vs. TGF (14%, 12/86 patients; p=0.37). Within the first two years, etiology of UPROR as a percentage of all patients per group were deep infection (5% TGF, 6% MCGR), implant failure/migration (5% TGF, 9% MCGR), dehiscence (2% TGF, 3% MCGR), and superficial infection (1% TGF, 3% MCGR). The most common etiology of UPROR for TGF was deep infection and implant failure/migration and for MCGR was implant failure/migration.

For patients with CP, at final follow-up, MCGR had superior maintenance of scoliosis correction; however, there was no difference in risk of UPROR within the first two years post-operatively (21% MCGR, 14% TGF).


P. Lapner S. McRae J. Leiter K. McIlquham P.B. MacDonald

Controversy exists regarding the optimal technique for arthroscopic rotator cuff repair. No previous comparative trials have reported on the long-term follow-up of single and double row fixation in arthroscopic cuff repair. The purpose of this study was to compare the long-term functional outcomes of single-row and double-row suture techniques for repair of the rotator cuff 10-years post-operatively.

Ninety patients undergoing arthroscopic rotator cuff repair were randomized to receive either single-row or double-row repair. The primary objective was to compare the Western Ontario Rotator Cuff Index (WORC) score 10-years post-operatively. Secondary objectives included comparison of the Constant, and American Shoulder and Elbow Surgeons (ASES) scores and supraspinatus strength between groups. Out of 90 patients originally randomized, 57 returned for the long-term 10-year follow-up.

Baseline demographic data did not differ between groups. The WORC score was not significantly different between groups at long-term follow-up (p=0.13). No statistical differences were observed between groups for the Constant (p=0.51), ASES (p=0.48) scores, or strength scores (p=0.93). A significant improvement was observed between pre-operative and the final 10-year follow-up. There were no differences observed in all outcomes between two and 10-years post-operatively.

No statistically significant differences in functional or quality of life outcomes were identified between single-row and double-row fixation techniques at long-term follow-up.


J. Woodmass S. McRae S. Malik J. Dubberley J. Marsh J. Old G. Stranges J. Leiter P.B. MacDonald

When compared to magnetic resonance imaging (MRI), ultrasound (US) performed by experienced users is an inexpensive tool that has good sensitivity and specificity for diagnosing rotator cuff (RC) tears. However, many practitioners are now utilizing in-office US with little to no formal training as an adjunct to clinical evaluation in the management of RC pathology. The purpose of our study was to determine if US without formal training is effective in managing patients with a suspected RC tear.

This was a single centre prospective observational study. Five fellowship-trained surgeons each examined 50 participants referred for a suspected RC tear (n= 250). Patients were screened prior to the consultation and were included if ≥ 40 years old, had an MRI of their affected shoulder, had failed conservative treatment of at least 6 months, and had ongoing pain and disability. Patients were excluded if they had glenohumeral instability, evidence of major joint trauma, or osteonecrosis. After routine clinical exam, surgeons recorded their treatment plan (“No Surgery”, “Uncertain”, or “Surgery”). Surgeons then performed an in-office diagnostic US followed by an MRI and documented their treatment plan after each imaging study. Interrater reliability was analyzed using a kappa statistic to compare clinical to ultrasound findings and ultrasound findings to MRI, normal and abnormal categorization of biceps, supraspinatus, and subscapularis.

Following clinical assessment, the treatment plan was recorded as “No Surgery” in 90 (36%), “Uncertain” in 96 (39%) of cases, “Surgery” in 61 (25%) cases, and incomplete in 3 (2%). In-office US allowed resolution of 68 (71%) of uncertain cases with 227 (88%) of patients having a definitive treatment plan. No patients in the “No Surgery” group had a change in treatment plan. After MRI, 16 (6%) patients in the “No Surgery” crossed-over to the “Surgery” group after identification of full-thickness tears, larger than expected tears or alternate pathology (e.g., labral tear).

The combination of clinical examination and in-office US may be an effective method in the initial management of patients with suspected rotator cuff pathology. Using this method, a definitive diagnosis and treatment plan was established in 88% of patients with the remaining 12% requiring an MRI. A small percentage (6%) of patients with larger than expected full-thickness rotator cuff tears and/or alternate glenohumeral pathology (e.g., labral tear) would be missed at initial evaluation.


P.B. MacDonald J. Woodmass S. McRae F. Verhulst P. Lapner

Management of the pathologic long-head biceps tendon remains controversial. Biceps tenotomy is a simple intervention but may result in visible deformity and subjective cramping. Comparatively, biceps tenodesis is technically challenging, and has increased operative times, and a more prolonged recovery. The purpose of this study was to determine the incidence of popeye deformity following biceps tenotomy versus tenodesis, identify predictors for developing a deformity, and compare subjective and objective outcomes between those that have one and those that do not.

Data for this study were collected as part of a randomized clinical trial comparing tenodesis versus tenotomy in the treatment of lesions of the long head of biceps tendon. Patients 18 years of age or older with an arthroscopy confirmed biceps lesion were randomized to one of these two techniques. The primary outcome measure for this sub-study was the rate of a popeye deformity at 24-months post-operative as determined by an evaluator blinded to group allocation. Secondary outcomes were patient reported presence/absence of a popeye deformity, satisfaction with the appearance of their arm, as well as pain and cramping on a VAS. Isometric elbow flexion and supination strength were also measured. Interrater reliability (Cohen's kappa) was calculated between patient and evaluator on the presence of a deformity, and logistic regression was used to identify predictors of its occurrence. Linear regression was performed to identify if age, gender, or BMI were predictive of satisfaction in appearance if a deformity was present.

Fifty-six participants were randomly assigned to each group of which 42 in the tenodesis group and 45 in the tenotomy group completed a 24-month follow-up. The incidence of popeye deformity was 9.5% (4/42) in the tenodesis group and 33% (15/45) in the tenotomy group (18 male, 1 female) with a relative risk of 3.5 (p=0.016). There was strong interrater agreement between evaluator and patient perceived deformity (kappa=0.636; p<0.001). Gender tended towards being a significant predictor of having a popeye with males having 6.6 greater odds (p=0.090). BMI also tended towards significance with lower BMI predictive of popeye deformity (OR 1.21; p=0.051). Age was not predictive (p=0.191). Mean (SD) satisfaction score regarding the appearance of their popeye deformity was 7.3 (2.6). Age was a significant predictor, with lower age associated with decreased satisfaction (F=14.951, adjusted r2=0.582, p=0.004), but there was no association with gender (p=0.083) or BMI (p=0.949). There were no differences in pain, cramping, or strength between those who had a popeye deformity and those who did not.

The risk of developing a popeye deformity was 3.5 times higher after tenotomy compared to tenodesis. Male gender and lower BMI tended towards being predictive of having a deformity; however, those with a high BMI may have had popeye deformities that were not as visually apparent to an examiner as those with a lower BMI. Younger patients were significantly less satisfied with a deformity despite no difference in functional outcomes at 24 months. Thus, biceps tenodesis may be favored in younger patients with low BMI to mitigate the risk of an unsatisfactory popeye deformity.


K. Farley J. Wilson C. Spencer A. Dawes C. Daly M. Gottschalk E. Wagner

The incidence of total shoulder arthroplasty (TSA) in increasing. Evidence in primary hip and knee arthroplasty suggest that preoperative opioid use is a risk factor for postoperative complication. This relationship in TSA is unknown. The purpose of this study was to investigate this relationship.

The Truven Marketscan claims database was used to identify patients who underwent a TSA and were enrolled for 1-year pre- and post-operatively. Preoperative opioid use status was used to divide patients into cohorts based on the number of preoperative prescriptions received. An ‘opioid holiday’ group (patients with a preoperative, 6-month opioid naïve period after chronic use) was also included. Patient information and complication data was collected. Univariate and multivariate logistic regression were then performed.

Fifty-six percent of identified patients received preoperative opioids. Multivariate analysis demonstrated that patients on continuous preoperative opioids (compared to opioid naïve) had higher odds of: infection (OR 2.34, 95%CI 1.62–3.36, p<0.001), wound complication (OR 1.97, 95%CI 1.18–3.27, p=0.009), any prosthetic complication (OR 2.62, 95%CI 2.2–3.13, p<0.001), and thromboembolic event (OR 1.42, 95%CI 1.11–1.83, p=0.006). The same group had higher healthcare utilization including extended length of stay, non-home discharge, readmission, and emergency department visits (p<0.001). This risk was reduced by a preoperative opioid holiday.

Opioid use prior to TSA is common and is associated with increased complications and healthcare utilization. This increased risk is modifiable, as a preoperative opioid holiday significantly reduced postoperative risk. Therefore, preoperative opioid use represents a modifiable risk factor.


L. Nowak D. Beaton M. Mamdani A. Davis J. Hall E.H. Schemitsch

The primary objectives of this study were to: 1) identify risk factors for subsequent surgery following initial treatment of proximal humerus fractures, stratified by initial treatment type; 2) generate risk prediction tools to predict subsequent shoulder surgery following initial treatment; and 3) internally validate the discriminative ability of each tool.

We identified patients ≥ 50 years with a diagnosis of proximal humerus fracture from 2004 to 2015 using linkable health datasets in Ontario, Canada. We used procedural and fee codes within 30 days of the index fracture to classify patients into treatment groups: 1) surgical fixation; 2) shoulder replacement; and 3) conservative. We used intervention and diagnosis codes to identify all instances of complication-related subsequent shoulder surgery following initial treatment within two years post fracture. We developed logistic regression models for randomly selected two thirds of each treatment group to evaluate the association of patient, fracture, surgical, and hospital variables on the odds of subsequent shoulder surgery following initial treatment. We used regression coefficients to compute points associated with each of the variables within each category, and calculated the risk associated with each point total using the regression equation. We used the final third of each cohort to evaluate the discriminative ability of the developed risk tools (via the continuous point total and a dichotomous point cut-off value for “higher” vs. “lower” risk determined by Receiver Operating Curves) using c-statistics.

We identified 20,897 patients with proximal humerus fractures that fit our inclusion criteria for analysis, 2,414 treated with fixation, 1,065 treated with replacement, and 17,418 treated conservatively. The proportions of patients who underwent subsequent shoulder surgery within two years were 13.8%, 5.1%, and 1.3%, for fixation, replacement, and conservative groups, respectively. Predictors of reoperation following fixation included the use of a bone graft, and fixation with a nail or wire vs. a plate. The only significant predictor of reoperation following replacement was poor bone quality. The only predictor of subsequent shoulder surgery following conservative treatment was more comorbidities while patients aged 70+, and those discharged home following initial presentation (vs. admitted or transferred to another facility) had lower odds of subsequent shoulder surgery. The risk tools developed were able to discriminate between patients who did or did not undergo subsequent shoulder surgery in the derivation cohorts with c-statistics of 0.75–0.88 (continuous point total), and 0.82–0.88 (dichotomous cut-off), and 0.53–0.78 (continuous point total) and 0.51–0.79 (dichotomous cut-off) in the validation cohorts.

Our results present potential factors associated with subsequent shoulder surgery following initial treatment of proximal humerus fractures, stratified by treatment type. Our developed risk tools showed good to strong discriminative ability in both the derivation and validation cohorts for patients treated with fixation, and conservatively. This indicates that the tools may be useful for clinicians and researchers. Future research is required to develop risk tools that incorporate clinical variables such as functional demands.


C. Bouchard R. Chan T. Bornes L. Beaupre A. Silveira R. Hemstock

The purpose of this study is to determine the re-operation rate following plate fixation of the olecranon with contoured anatomic plates.

Plate fixation of the olecranon allows for management of different fracture patterns as well as osteotomies with anatomic reduction and stable fixation for early elbow mobilization. However, olecranon hardware prominence can be troublesome. Our hypothesis was with the newer generation of low profile contoured anatomic plates, the rate of hardware removal should be lower compared to previously described literature. Retrospective review for patients treated with operative fixation of the olecranon between 2010 and 2015 in the Edmonton zone was identified using population level administrative data. Radiographic screening of these patients was then carried out to identify those who received plate fixation. Fracture patterns were also characterized. Chart reviews followed to determine the indications for re-operation and other post-operative complications. Main outcome measures were re-operation rate and their indications, including hardware prominence.

During the screening process, 600 surgically treated olecranon patients were identified and 321 patients were found to have plate fixation of the olecranon. Chart review determined 90 patients had re-operations demonstrating a 28% re-operation rate. Re-operation due to hardware prominence was found to be 15.6%. Other indications included hardware failure (5.3%), infection (2.8%), or contracture (2.8%). Compared to patients that did not require re-operation, the re-operation group had a higher incidence of Type III olecranon fractures (17.4% vs 8.4%, p = 0.036) and Monteggia pattern injuries (13.5% vs 4.9%, p = 0.008).

Recent heteregenous data suggests the hardware removal rate related to implant prominence is between 17–54%. Compared to the literature, this study demonstrated a lower rate at 15.6% with contoured anatomic plating. Also, those with more complex fracture patterns were more likely to require re-operation.


A. Tavakoli K.J. Faber G.D. Langohr

Total shoulder arthroplasty (TSA) is an effective treatment for end-stage glenohumeral arthritis. The use of high modulus uncemented stems causes stress shielding and induces bone resorption of up to 63% of patients following TSA. Shorter length stems with smaller overall dimensions have been studied to reduce stress shielding, however the effect of humeral short stem varus-valgus positioning on bone stress is not known. The purpose of this study was to quantify the effect of humeral short stem varus-valgus angulation on bone stresses after TSA.

Three dimensional models of eight male cadaveric humeri (mean±SD age:68±6 years) were created from computed tomography data using MIMICS (Materialise, Belgium). Separate cortical and trabecular bone sections were created, and the resulting bone models were virtually reconstructed three times by an orthopaedic surgeon using an optimally sized short stem humeral implant (Exactech Preserve) that was placed directly in the center of the humeral canal (STD), as well as rotated varus (VAR) or valgus (VAL) until it was contacting the cortex. Bone was meshed using a custom technique which produced identical bone meshes permitting the direct element-to-element comparison of bone stress. Cortical bone was assigned an elastic modulus of 20 GPa and a Poisson's ratio of 0.3. Trabecular bone was assigned varying stiffness based on CT attenuation. A joint reaction force was then applied to the intact and reconstructed humeri representing 45˚ and 75˚ of abduction. Changes in bone stress, as well as the expected bone response based on change in strain energy density was then compared between the intact and reconstructed states for all implant positions.

Both varus and valgus positioning of the humeral stem altered both the cortical and trabecular bone stresses from the intact states. Valgus positioning had the greatest negative effect in the lateral quadrant for both cortical and trabecular bone, producing greater stress shielding than both the standard and varus positioned implant. Overall, the varus and standard positions produced values that most closely mimicked the intact state.

Surprisingly, valgus positioning produced large amounts of stress shielding in the lateral cortex at both 45˚ and 75˚ of abduction but resulted in a slight decrease in stress shielding in the medial quadrant directly beneath the humeral resection plane. This might have been a result of direct contact between the distal end of the implant and the medial cortex under loading which permitted load transfer, and therefore load-reduction of the lateral cortex during abduction. Conversely, when the implant was placed in the varus angulation, noticeable departures in stress shielding and changes in bones stress were not observed when compared to the optimal STD position. Interestingly, for the varus positioned implant, the deflection of the humerus under load eliminated the distal stem-cortex contact, hence preventing distal load transfer thus precluding the transfer of load.


M. Aziz D. Rosenzweig M. Weber

Great strides have been made in the early detection and treatment of cancer which is resulting in improved survivability and more Canadians living with cancer. Approximately 80% of primary breast, lung, and prostate cancers metastasize to the spine. Poly-methyl methacrylate (PMMA) bone cement is one of the most commonly used bone substitutes in spine surgery. In clinical practice it can be loaded with various drugs, such as antibiotics or chemotheraputic drugs, as a means of local drug delivery. However, studies have shown that drugs loaded into PMMA cement tend to release in small bursts in the first 48–72 hours, and the remaining drug is trapped without any significant release over time. The objective of this study is to develop a nanoparticle-functionalized PMMA cement for use as a sustained doxorubicin delivery device. We hypothesize that PMMA cement containing mesoporous silica nanoparticles will release more doxorubicin than regular PMMA.

High viscosity SmartSet ™ PMMA cement by DePuy Synthes was used in this study. The experimental group consisted of 3 replicates each containing 0.24 g of mesoporous silica nanoparticles, 1.76 g of cement powder, 1ml of liquid cement monomer and 1 mg of doxorubicin. The control group consisted 3 replicates each containing 2.0 g of cement powder, 1ml of liquid cement monomer and 1 mg of doxorubicin. The experimental group contained an average of 8.18 ± 0.008 % (W/W) mesoporous silica nanoparticles. Each replicate was casted into a cylindrical block and incubated in a PBS solution which was changed at predetermined intervals for 45 days. The concentration of eluted doxorubicin in each solution was measured using a florescent plate reader. The mechanical properties of cement were assessed by unconfined compression testing. The effect of the doxorubicin released from cement on prostate and breast tumor cell metabolic activity was assessed using the Alamar Blue test.

After 45 days the experimental group released 3.24 ± 0.25 % of the initially loaded doxorubicin which was more than the 2.12 ± 0.005% released by the control group (p 0.03). There was no statistically significant difference in Young's elasticity modulus between groups (p 0.53). Nanoparticle functionalized PMMA suppressed the metabolic activity of prostate cancer by more than 50 percent but did not reach statistical significance. Nanoparticle functionalized PMMA suppressed the metabolic activity of breast cancer cells by 69 % (p < 0.05).

Nanoparticle-functionalized PMMA cement can release up to 1.53 times more doxorubicin than the standard PMMA. The use of mesoporous silica nanoparticles to improve drug release from PMMA cement shows promise. In the future, in vivo experiments are required to test the efficacy of released doxorubicin on tumor cell growth.


T. Chen S. Christie A.J.M. Yee S. Yoon C. Fisher P.F. Jarzem J. Roy J.A. Bouchard

There is a paucity of published Canadian literature comparing lumbar total disc arthroplasty (LDA) to fusion on patient outcomes in degenerative spondylosis. The purpose of this study is to quantify and compare the long-term patient reported outcomes following LDA and matched-fusion procedures.

We conducted a matched-cohort study comparing consecutive patients enrolled by CSORN who underwent standalone primary LDA or hybrid techniques for degenerative disk disease between 2015–2019. Fusion patients were included by a primary diagnosis of degenerative disk disease, chief complaint of back pain, who received a primary fusion irrespective of technique. Fusion patients were matched by number of involved levels of surgery to LDA counterparts. Outcome scores and patient satisfaction were assessed preoperatively and 2-years postoperatively.

97 patients (39-female, 58-male) underwent LDA or hybrid construct up to 4 levels. 94 patients (52-female, 42-male) underwent a lumbar fusion were selected based on inclusion criteria. 36 LDA and 57 Fusion patients underwent a 1-level surgery. 39 LDA and 25 Fusion patients underwent 2-level surgery. 18 LDA and 7 Fusion patients underwent 3-level surgery. 4 LDA and 5 Fusion patients underwent a 4-level procedure. Slight differences in average cohort age were found (LDA-43.4yrs, Fusion-49.8yrs, p<0.01). Cohort preoperative-BMI (LDA-27.0kg/m2, Fusion-27.9kg/m2, p=0.29) and total comorbidities (LDA-2.6, Fusion-2.1, p=0.05) demonstrated no clinically significant differences. At 2 year follow-up, no differences were found in ODI improvement (LDA-20.32pts, Fusion-17.02pts, p=0.36), numerical back-pain improvement (LDA-3.5pts, Fusion-3.06pts, p=0.40), numerical leg-pain improvement (LDA-1.67pts, Fusion-1.87pts, p=0.76), and Health Scale improvement (LDA-17.12, Fusion-10.73, p=0.20) between cohorts. Similar positive findings were found in subgroups stratified by number of surgical levels. Satisfaction rate at 2 years was 86.7% and 82.4% for LDA and Fusion patients respectively.

There didn't appear to be significant differences in outcomes or satisfaction through 2 years comparing patients who underwent LDA (whether used in isolation or as part of a hybrid construct) for debilitating degenerative disk disease and isolated spinal fusion for back dominant pain.


P. Beauchamp-Chalifour J. Street A. Flexman R. Charest-Morin

Frailty has been shown to be a risk predictor for peri-operative adverse events (AEs) in patients undergoing various type of spine surgery. However, its relationship with Patient Related Outcome Measures (PROMS) remains unknown. The primary objective of this study was to determine the impact of frailty on PROMS in patients undergoing surgery for thoraco-lumbar degenerative conditions. The secondary objective was to determine the association between frailty and baseline PROMS.

This is a retrospective study of a prospective cohort of patients >55 years old who underwent surgery between 2012 and 2018. Patient data and PROMS (EQ-5D, SF-12, ODI, back and leg pain NRS) were extracted from the Canadian Spine Outcomes and Research Network registry for a single academic centre. Frailty was retrospectively calculated using the modified frailty index (mFI) and patient were classified as frail, pre-frail and non-frail. Patient characteristics and outcomes were analyzed using ANOVA or Kruskal-Wallis test for continuous variables and Chi square or Fisher's exact test for proportions. A generalized estimating equations (GEEs) regression model was used to assess the association between patients' baseline frailty status and PROMs measures at three and 12 months.

293 patients were included with a mean age of 67 ± 7 years. Twenty-two percent of the patients (n= 65) were frail, 59 % (n=172) were pre-frail and 19% (n=56) were non-frail. At baseline, the three groups had similar PROMS, except for the PCS which was worse in the frail group (mean difference [95% CI], −4.9 [−8.6;-1.1], p= 0.0083). The improvement in the EQ-5D, PCS, MCS, ODI, back and leg pain NRS scores was not significantly different between the three groups (p> 0.05). The was no difference in the evolution of the PROMS at three and 12 months between the three groups (p> 0.05).

Although frailty is a known predictor of AEs, it does not predict worse PROMS after spine surgery in that population. At baseline, non-frail, pre-frail and frail patients have similar PROMS.


F. Moldovan S. Parent S. Barchi A. Hassan K. Patten

The etiology of adolescent idiopathic scoliosis (AIS) is largely unknown, but clinical observations revealed the role of hereditary and rapid growth in the development of this condition. More recently, several genes were suspected to cause or contribute to AIS. Our group identified gene variants of POC5 centriolar protein in a French and French-Canadian families with multiple members affected with AIS. We sought to expand on this study and to investigate for the role of POC5 gene and mutated protein. In this work, the potential pathogenic effect of mutated POC5 was investigated in vitro (human osteoblats cell culture) and in vivo in a zebrafish animal model.

To investigate the role of POC5 in AIS, we investigated subcellular localization of POC5 with respect to cilia in cells overexpressing wt or POC5 variants (C1286T, A429V) and in human osteoblasts from scoliotic patients carrying these POC5 variants and normal control cells (in vitro study). We also created a loss-of-function model in zebrafish (in vivo study). The role of POC5 was investigated by: 1) mass spectroscopy analysis and co-immunoprecipitation to identify differences in binding partners between the wild-type (wt POC5 and mut POC5 protein; 2) immunolocalization of POC5 wt and mut proteins at the cellular level; 3) histology and immunohistochemistry performed on tissues from wt (control) and scoliotic (poc5 mut) zebrafish.

Our work identified several interacting partners with POC5, and documented functional connections with respect to cilia and centrosome dysfunction. A number of ciliary proteins were identified to be interacting with wt POC5 but not mut POC5. At the cellular level, localization and co-localisation of wt POC5 and mut POC5 protein with alpha acetylated tubulin (cilia marker), confirmed the consequence of the mutation on subcellular location with respect to cilium structure, length and staining intensity of cilia. In vivo, several defects in the retina were identified in mut poc5 zebrafish compared wt zebrafish. Finally, using different markers for retinal layers and acetylated tubulin, the defects were localized in ganglion cell layer and cones of the retina.

Our findings confirm the involvement of POC5 in scoliosis. A role of POC5 with respect to the primary cilia was attributed. These findings open new avenues for the understanding the primary causes of AIS at the molecular and physiological levels.


R.A. Glennie C. Bailey R.Y. Rampersaud C. Fisher

Instrumented fusion for lumbar degenerative spondylolisthesis (LDS) has been challenged recently with high impact trials demonstrating similar changes in health-related quality of life (HRQOL) and less morbidity/cost with laminectomy alone. Randomized trials often fail, however, to evaluate a heterogeneous population of patients. A standardized clinical assessment and management plan (SCAMP) was created as a decision aid for surgeons based on the radiographic stability and clinical presentation of patients. The purpose of this study was to compare outcomes of those patients who followed the decision aid with respect to fusion/no fusion to those who did not.

Patients were prospectively enrolled from eleven different Canadian institutions and followed from 2015–2019. A degenerative spondylolisthesis instability classification system (DSIC) was created using best available evidence stratifying patients into three different subtypes (1. stable degenerative spondylolisthesis, 2. potentially unstable spondylolisthesis and 3. unstable spondylolisthesis). The decision aid recommends laminectomy alone for group 1 patients, posterolateral fusion with pedicle screws in type 2 patients and pedicle screw and interbody fusion for type 3 patients. One year changes in HRQOL, length of hospital stay (LOS), medication use and surgical time were compared between each group and in context of whether the treatment fell within the decision aid recommendation. Statistics were performed with STATA software.

There were 394 patients initially enrolled and 334 (84.8%) with full one year data available for comparison. There were 95 type 1 (stable), 224 type 2 (potentially unstable) and 75 type 3 (unstable) patients initially classified. Baseline Ostwestry disability index (ODI), EQ-5D, and SF-12 MCS scores were significantly worse for type 3 patients versus type 1 patients. One hundred and eight patients were treated within the recommendations of the DSIC system (108/334, 32.3%). Surgeons performed interbody fusions in 141 patients (42%) rather than follow DSIC recommending a less invasive approach. There were no significant differences EQ-5D, SF-12 PCS/MCS, PHQ-9 or ODI at one year between patient groups. There was a trend towards shorter operating times for those patients following the DSIC system (195 minutes non-followers versus 180 followers, p=0.078) and reduced hospital stay (4.46 days non-followers versus 3.98 followers, p=0.065).

There were no significant clinical differences in outcome at 1 year whether patients underwent decompression alone, decompression/posterolateral fusion or interbody fusion regardless of the stability classification. Surgeons were more likely to perform potentially unnecessary interbody fusions even in those patients with stable or potentially unstable spondylolisthesis. Although not statistically significant, there is some suggestion that following the DSIC system based on best evidence recommendations leads to more judicious/responsible use of hospital resources. Further study is required to determine why surgeons are more likely to choose more invasive, higher rigidity constructs in patients with LDS.


D.F. Vogel A. Finless G. Grammatopoulos J. Dobransky P. Beaulé R. Ojaghi

Surgical treatment options for Femoroacetabular impingement (FAI) includes both surgical dislocation and hip arthroscopy techniques. The primary aim of this study was to evaluate and compare the survivorship of arthroscopies (scope) and surgical dislocations (SD) at minimum 5-year follow-up. The secondary aim was to describe differences in functional outcomes between the 2 groups.

This was a retrospective, single surgeon, consecutive, case-series from a large tertiary care centre. We evaluated all surgeries that were performed between 2005 and 2011. Our institutional database was queried for any patient undergoing surgery for FAI (pincer (n=23), cam (n=306), or mixed (n=103) types). Patients with childhood pathologies i.e. Legg Calve Perthes and slipped capital femoral epiphysis were excluded. This resulted in 221 hips (169 males, 52 females) who underwent either SD (94, 42.5%) or scope (127, 57.5%). A manual chart review was completed to identify patients who sustained a complication, underwent revision surgery or progressed to a total hip arthroplasty (THA). In addition, we reviewed prospectively collected patient reported outcome measure (PROMs) using (SF12, HOOS, and UCLA). Survivorship outcome was described for the whole cohort and compared between the 2 surgical groups. PROMs between groups were compared using The Mann-Whitney U test and the survival between groups was assessed using the Kaplan-Meier Analysis and the Log-Rank Mantel Cox test. All analyses were performed in SPSS (IBM, v. 26.0).

The cohort included 110 SDs and 320 arthroscopies. The mean age of the whole cohort was 34±10; patients in the SD group (32±9) were younger compared to the arthroscopy group (39±10) (p<0.0001). There were 16 post-operative complications (similar between groups) and 77 re-operations (more common in the SD group (n=49) due to symptomatic metal work (n=34)). The overall 10-year survival was 91±3%. Survivorship was superior in the arthroscopy group at both 5- (96% (95%CI: 93 – 100)) and 8- years 94% (95%CI: 90 – 99%) compared to the SD Group (5-yr: 90% (95%CI: 83 – 98); 8-yr: 84% (95%CI:75 – 93)) (p=0.003) (Figure 1). On average HOOS improved from 54±19 to 68±22 and WOMAC from 65±22 to 75±22. The improvement in PROMs were similar between the 2 groups.

We report very good long-term joint preservation for the treatment of FAI, which is similar to those reported in hip dysplasia. In addition, we report satisfactory improvement in function following such treatment. The differences reported in joint survival likely reflect selection biases from the treating surgeon; more complex cases and those associated with more complex anatomy were more likely to have been offered a SD in order to address the pathology with greater ease and hence the inferior joint preservation identified in this group.

For any figures or tables, please contact the authors directly.


T. Bolley J. Kellum D. Yao C. Snyder J. Grant

Limb symmetry on a battery of functional tests is becoming more common as a clinical rehabilitation tool serving as a proxy assessment for readiness to return to sport following anterior cruciate ligament reconstruction (ACLR). The predictive capability of each included test for determining the likelihood of a second ACL injury is not well known. This study combines 14 established functional tests into a comprehensive return-to-sport assessment (RTSA). Study purpose: to determine if any of the functional tests were independently related to a second ACL injury occurring after the patient was cleared for return to sport.

The RTSA was administered to 226 individuals after primary, unilateral ACLR who were followed for at least 24 months (51% female; mean ± SD age, 18.9 ± 4.0 years at RTSA, 9.4 ± 2.4 months post-surgery). The RTSA included 14 tests that involved calculation of Limb Symmetry Indices (LSI): leg press [LP], eccentric hamstring strength [HS], hip adductor strength [HA], Y Balance Test (anterior [YANT], posteromedial [YPM], posterolateral [YPL]), single hop [SH], triple hop [TH], crossover hop [CH], 6 meter timed hop [TiH], lateral hop [LH], medial hop [MH], vertical jump [VJ], single leg squat [SLS]. LSI averaged values of three trials for each leg for LP, HS, HA, SH, TH, CH, TiH, LH, MH, VJ, and SLS. The lowest bilateral difference across three trials was used for YANT, YPM, and YPL. Logistic regression using backward elimination was used to predict the odds of a second non-contact ACL injury using the RTSA, sex, age, and months post-surgery at RTSA as the independent variables.

Twenty-five (11%) patients returned to have a subsequent ACL surgery. Twenty of the 25 experienced a second non-contact ACL injury (70% female; 10 ipsilateral, 10 contralateral). Of the 14 female athletes, there were eight contralateral and six ipsilateral tears. In males, there were two contralateral and four ipsilateral tears. The mean time from surgery to injury was 20.5 ± 9.8 months. Age (OR; 95%CI: 0.75; 0.58, 0.92), LP (0.97; 0.93, 0.99), YANT (1.21; 1.02, 1.43), and TiH (1.10; 1.01, 1.20) were found to be significantly associated with the odds of re-injury.

Age, YANT, and the LSI of LP and TiH have a statistically significant impact on the odds of a second ACL injury after ACL reconstruction. YANT has an OR of 1.21, indicating that a 1cm increase in asymmetry will increase the likelihood of re-injury by 21%, holding all else constant. A 1% increase in the TiH LSI results in a 10% increase in the odds of re-injury. The risk of re-injury decreases as age increases. The OR for LP symmetry was near 1.0 and therefore may not have a clinically relevant effect on re-injury risk. Although LSI is a straightforward, quantitative measure, clinicians should not solely rely on it as a proxy for recovery of knee function. Many tests are available for clinical assessments, but this study found only a few of the tests to have significant associations with a subsequent ACL injury following return to play after ACL reconstruction.


L.A. Hiemstra S. Kerslake

MPFL reconstruction has demonstrated a very high success rate with improved patella stability, physical function, and patient-reported outcomes. However technical error and a lack of consideration of anatomic risk factors have been shown to contribute to failure after MPFL reconstruction. Previous research has also reported a complication rate of 26% following surgery. The purposes of this study were to determine the re-dislocation rate, type and number of complications, and most common additional surgical procedures following MPFL reconstruction.

Patients with symptomatic recurrent patellofemoral instability underwent an MPFL reconstruction (n = 268) and were assessed with a mean follow-up of 31.5 months (minimally 24-months). Concomitant procedures were performed in addition to the MPFL reconstruction in order to address significant anatomic or biomechanical characteristics. Failure of the patellofemoral stabilization procedure was defined as post-operative re-dislocation of the patella. Rates of complications and re-procedures were assessed for all patients.

The re-dislocation rate following MPFL reconstruction was 5.6% (15/268). There were no patella fractures. A total of 49/268 patients (18.3%) returned to the operating room for additional procedures following surgery. The most common reason for additonal surgery was removal of symptomatic tibial tubercle osteotomy hardware in 24/268 patients (8.9%). A further 9.3% of patients underwent addtional surgery including revision MPFL reconstruction: with trochleoplasty 8/268 (3.0%), with tibial tubercule osteotomy 4/286 (1.5%) and with femoral derotation osteotomy 3/268 (1.1%); manipulation under anaesthesia for reduced knee range of motion 4/268 (1.5%); knee arthroscopy for pain 8/268 (3.0%); and cartilage restoration procedures 3/268 (1.1%). There was 1 case of wound debridement for surgical incision infection.

MPFL reconstruction using an a la carte approach to surgical selection demonstrated a post-operative redislocation rate of 5.6%. The rate of complications following surgical stabilization was low, with the most common reason for additional surgery being removal of hardware.


K. Martin A. Persson G. Moatshe A.M. Fenstad L. Engebretsen H. Visnes

Surgery performed in low-volume centres has been associated with longer operating time, longer hospital stays, lower functional outcomes, and higher rates of revision surgery, complications, and mortality. This has been reported consistently in the arthroplasty literature, but there is a paucity of data regarding the relationship between surgical volume and outcome following anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to compare the ACL reconstruction failure rate between hospitals performing different annual surgical volumes. The hypothesis was that ACL reconstructions performed at low-volume hospitals would be associated with higher failure rates than those performed at high-volume centres.

This level-II cohort study included all patients from the Norwegian Knee Ligament Registry that underwent isolated primary autograft ACL reconstruction between 2004 and 2016. Hospital volume was divided into quintiles based on the number of ACL reconstructions performed annually, defined arbitrarily as: 1–12 (V1), 13–24 (V2), 25–49 (V3), 50–99 (V4), and ≥100 (V5) annual procedures. Kaplan-Meier estimated survival curves and survival percentages were calculated with revision ACL reconstruction as the end point. Mean change in Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life and Sport subsections from pre-operative to two-year follow-up were compared using t-test.

19,204 patients met the inclusion criteria and 1,103 (5.7%) underwent subsequent revision ACL reconstruction over the study period. Patients in the lower volume categories (V1-3) were more often male (58–59% vs. 54–55% p=<0.001) and older (27 years vs. 24–25 years, p=<0.001) compared to the higher volume hospitals (V4-5). Concomitant meniscal injuries (52% vs. 40%) and participation in pivoting sports (63% vs. 56%) were most common in V5 compared with V1 (p=<0.001). Median operative time decreased as hospital volume increased, ranging from 90 minutes at V1 hospitals to 56 minutes at V5 hospitals (p=<0.005). Complications occurred at a rate of 3.8% at low-volume (V1) hospitals versus 1.9% at high-volume (V5) hospitals (p=<0.001). Unadjusted 10-year survival with 95% confidence intervals for each hospital volume category were: V1 – 95.1% (93.7–96.5%), V2 – 94.1% (93.1–95.1%), V3 – 94.2% (93.6–94.8%), V4 – 92.6% (91.8–93.4%), and V5 – 91.9% (90.9–92.9%). There was no difference in improvement between pre-operative and two-year follow-up KOOS scores between hospital volume categories.

Patients having ACL reconstruction at lower volume hospitals did not have inferior clinical or patient reported outcomes, and actually demonstrated a lower revision rate. Complications occurred more frequently however, and operative duration was longer. The decreased revision rate is an interesting finding that may be partly explained by the fact that patients being treated in these small, often rural hospitals, may be of lower demand as suggested by the increased age and decreased participation in pivoting sports. In addition, patients with more complicated pathology such as meniscal tears were more commonly treated in the larger volume hospitals. The most significant limitation of this study is that provider volume was not assessed, and the number of surgeons dividing up the surgical volume at each hospital is not known.


N. Matthies R. Paul T. Dwyer D.B. Whelan J. Chahal

Quadriceps tendon ruptures are a rare but debilitating injury resulting in loss of knee extension necessitating surgical intervention. Currently, multiple different surgical techniques and rehabilitation programs are utilized by surgeons. Researchers have been unable to determine the best surgical technique with respect to function and complication rate; certain techniques are more cost-effective than others. Early vs. late motion rehabilitation programs are utilized; recent evidence suggests that less aggressive initial rehabilitation may lead to decreased extensor lag and fewer additional surgeries. The goal of our study is to determine the treatment practices of orthopaedic surgeons across Canada.

Our study was completed anonymously via SurveyMonkey.com (Palo Alto, California). Based on current literature, a 26-question survey was distributed. E-mail invitations were be sent to all members of the Canadian Orthopaedic Association. Participation is voluntary.

Currently, 104 surveys have been completed. 78% of respondents utilize transosseous drill holes, 13% utilize suture anchors and 9% utilize a combined surgical technique. The majority of surgeons begin range of motion (ROM) at 2 weeks (42%) or 6 weeks (24%); ROM is then commonly progressed in a step-wise fashion at 2-week intervals (58%). Approximately half of respondents have performed revision surgery for quadriceps re-rupture.

Surgical management of quadriceps tendon ruptures is fairly consistent amongst Canadian orthopaedic surgeons. However, wide variation exists regarding rehabilitation, favoring early initiation and progression of ROM despite some evidence recommending a longer period of immobilization.


N. Pasic R. Degen T. Burkhart

Hip arthroscopy rates continue to increase. As a result, there is growing interest in capsular management techniques. Without careful preservation and surgical techniques, failure of the repair result in capsular deficiency, contributing to iatrogenic instability and persistent post-operative pain. In this setting, capsular reconstruction may be indicated, however there is a paucity of objective evidence comparing surgical techniques to identify the optimal method. Therefore, the objective of this study was to evaluate the biomechanical effect of capsulectomy and two different capsular reconstruction techniques (iliotibial band [ITB] autograft and Achilles tendon allograft) on hip joint kinematics in both rotation and abduction/adduction.

Eight paired fresh-frozen hemi-pelvises were dissected of all overlying soft tissue, with the exception of the hip joint capsule. The femur was potted and attached to a load cell connected to a joint-motion simulator, while the pelvis was secured to a custom-designed fixture allowing adjustment of the flexion-extension arc. Optotrak markers were rigidly attached to the femur and pelvis to track motion of the femoral head with respect to the acetabulum. Pairs were divided into ITB or Achilles capsular reconstruction. After specimen preparation, three conditions were tested: (1) intact, (2) after capsulectomy, and (3) capsular reconstruction (ITB or Achilles). All conditions were tested in 0°, 45°, and 90° of flexion. Internal rotation (IR) and external rotation (ER) as well abduction (ABD) and adduction (ADD) moments of 3 N·m were applied to the femur via the load cell at each position. Rotational range of motion and joint kinematics were recorded.

When a rotational force was applied the total magnitude of internal/external rotation was significantly affected by the condition of the capsule, independent of the type of reconstruction that was performed (p=0.001). The internal/external rotation increased significantly by approximately 8° following the capsulectomy (p<0.001) and this was not resolved by either of the reconstructions; there remained a significant difference between the intact and reconstruction conditions (p=0.035). The total anterior/posterior translation was significantly affected by the condition of the capsule (p=0.034). There was a significant increase from 6.7 (6.0) mm when the capsule was intact to 9.0 (6.7) mm following the capsulectomy (p=0.002). Both of the reconstructions (8.6 [5.6] mm) reduced the anterior/posterior translation closer to the intact state. There was no difference between the two reconstructions. When an abduction/adduction force was applied there was a significant increase in the medial-lateral translation between the intact and capsulectomy states (p=0.047).

Across all three flexion angles the integrity of the native hip capsule played a significant role in rotational stability, where capsulectomy significantly increased rotational ROM. Hip capsule reconstruction did not restore rotational stability and also increased rotational ROM compared to the intact state a statistically significant amount. However, hip capsule reconstruction restored coronal and sagittal plane stability to approach that of the native hip. There was no difference in stability between ITB and Achilles reconstructions across all testing conditions.


D. Rouleau P. Goetti M. Nault J. Davies E. Sandman

Recurrent anterior shoulder instability (RASI) is related to progressive bone loss on the glenoid and on the humeral head. Bone deficit magnitude is a well-recognized predictor of recurrence of instability after an arthroscopic Bankart surgery, but the best way to measure it is unknown. In this study, we want to determine which measurement method is the best predictor of recurrence of instability and function.

For 10 years now, all patients undergoing surgery for RASI in 4 centers are included in a prospective study: the LUXE cohort. Patients with a pre-operative CT-scan and a minimum of 1-year follow-up were included. ISIS score was used to stratify patients. WOSI and Quick-Dash questionnaires were used to characterise function. Bone defects were assessed using the Clock method, the Glenoid Ratio, the Humeral Ratio, the Glenoid Track method and the angle of engagement in the axial plane.

A total of 262 patients are now included in the LUXE study. One hundred and three patients met the inclusion criteria for analysis with a majority of male (79%) and a mean age is 28 years old. The median number of dislocations prior to surgery was 6. Seventy patients had an arthroscopic Bankart repair and 33 patients underwent an open Latarjet procedure. The ISIS score for these groups were of 2.7 and 4.8 respectively (p<0.001). The mean bone defect on the glenoid was of 1h51 with the Clock method (range: 0h-4h48; SD=1h46) and of 9% for the glenoid ratio (0–37%, 10%). On the humeral side, the bone defect was of 1h59 (0h-4h08; 0h49) for the Humeral clock method, 15% (0–36%; 6%) with the ratio method and 71 degrees of external rotation (SD=30 degrees) with the angle of engagement measurement. On the combined evaluations, 53 patients presented an off-track lesion, with mean combined hours of 3h53 (SD= 2h13). The greatest correlation obtained was between the glenoid ratio and the glenoid clock method (r=0.919, p<0.001). Eighteen patients had a recurrence of shoulder dislocation after the initial surgery, leading to a recurrence rate of 23% in arthroscopic surgery versus six percent after a Latarjet (OR= 4.6, p=0.034). No bone defect was correlated to Latarjet failure. For the arthroscopic group, the risk of recurrence was related to a smaller angle of engagement of the Hill-Sachs (p=0.05), a smaller Humeral clock measurement (p=0.034) and a longer follow-up (p=0.006). No glenoid or combined measurements were correlated with arthroscopic procedure failure. Recurrence of dislocation was associated to worst function according to the WOSI (1036 vs 573, p=0.002) and DASH (32 vs 15, p=0.03).

Even with lower ISIS score, arthroscopic procedures are still leading to high risk of recurrence in this “all comer” consecutive cohort study AND it is related to humeral side parameters. Recurrence is also affecting daily function and creating higher anxiety related to the shoulder.


G. Larose S. McRae A. Beaudoin R.G. McCormack P.B. MacDonald

There is increasing evidence that patients with ACL reconstruction using ipsilateral graft harvest are at greater risk of rupture (12.5%) on their contralateral compared to their surgical side (7.9%). The purpose of this study is to re-evaluate patients from a previous study comparing ipsi- versus contralateral graft harvest to compare ACL rupture rate at a minimum 10 year follow-up.

An attempt to contact all participants from a previously published study was made to invite them to return for a follow-up. The assessment included an International Knee Documentation Committee Knee Clinical Assessment (IKDC), isokinetic concentric knee flexion and extension strength testing, as well as the ACL-Quality of life (ACL-QOL). A chart review was conducted to identify or confirm subsequent ipsi- or contralateral knee surgeries.

In patients with ipsilateral graft, 3/34 (8.8%) re-ruptured and 3/34 (8.8%) had contralateral rupture. In the contralateral group, 1/28 (3.6%) re-ruptured and 2/28 (7.1%) had contralateral rupture. The relative risk (RR) of re-rupture with ipsilateral graft was 2.47 compared to using the contralateral site (p=0.42). RR of rupture on the contralateral side when ipsilateral graft was used was 1.23 compared to the alternate approach. Current contact information was unavailable for 21 patients. Of the 47 remaining, 37 were consented (79%). No difference in the ACL-QOL between groups (ipsilateral 68.4±24.4, contralateral 80.1±16.0, p=0.17) was observed. There were no differences in knee flexion strength between groups (peak torque flexion affected leg: ipsilateral 77.8nm/kg±27.4, contralateral: 90.0 nm/kg±35.1; p=0.32; Unaffected leg: ipsilateral: 83.3 nm/kg±30.2 contralateral 81.7 nm/kg±24.4; p= 0.89).

This study suggests that using the contralateral hamstring in ACL rupture is not associated with an increase in ACL rupture on either side. The risk of ACL injury was low in all limbs; therefore, a larger study would be required to definitively state that graft side had no impact.


N. Karatzas J. Corban S. Bergeron T. Fevens P.A. Martineau

A quick, portable and reliable tool for predicting ACL injury could be an invaluable instrument for athletes, coaches, and clinicians. The gold standard, Vicon motion analysis, despite having a high sensitivity and risk specificity, is not practical for coaches or clinicians to use on a routine basis for assessing athletes. The present study validated the Kinect device to the currently used method of chart review in predicting athletes at high risk.

A total of 114 participants were recruited from both the men and women McGill Varsity Sports Program. 69 males and 45 female athletes were evaluated to assess the specificity and sensitivity of the Kinect device in predicting athletes at high risk of injury. Each athlete performed three-drop vertical jumps off of a 31cm box and the data was recorded and risk score was generated. Generation of this data is done by our uniquely programmed software that measures landing angles at different time frames and compares live results to previously known data of injured athletes. A chart review was then performed by a clinician, blinded to these risk scores, to risk stratify the same athletes as high or low risk of ACL injury based on their medical charts. Data reviewed incorporated pre-season physical exams along with documented known risk factors for ACL injury, including previous knee injuries, family history of ACL injury, gender, sport, and BMI. Positive risk factors were assigned one point while negative risk factors assigned zero points.

The Kinect device, powered by our software, identified 40 athletes as having a high-risk score (> 55%), and subsequently, five (4.39%) sustained an ACL injury by the end of their respective sport seasons. Two male and two female basketball players along with one male soccer player sustained non-contact ACL injuries. Given that all five of the injured athletes were in the cohort of 40 identified as high risk by the Kinect, this yielded a sensitivity of 100% for the device. As for the specificity, the Kinect computed 35 false positives, yielding a specificity of 68% for the duration of the study. The medical chart review identified 36 athletes as high risk and 60 as being low risk of ACL injury. Four of the athletes that sustained an ACL injury were in the group of 36 identified as high risk by the clinician. However, one of the five participants who sustained an ACL injury was not captured by the medical chart assessment, yielding a sensitivity of 80% and a specificity of 65% for the clinician.

When it comes to injury prediction, it is preferred to have a high sensitivity even if the specificity is slightly lower as this ensures that all athletes who are at risk will be captured. Our data demonstrated that the chart analysis provided one false negative and led to missing one high-risk athlete who ended up sustaining an ACL injury. Based on the comparison of sensitivity and specificity, the Kinect system provides a slightly better predictive analysis for predicting ACL injury compared to chart review.


O. Cheng N. Law J. Tulk

A significant proportion of patient transfers in Ontario are from long-term care facilities for consultation of musculoskeletal (MSK) issues. These transfers are costly for patients and the healthcare system. This study evaluated the utility of a Telemedicine MSK (TeleMSK) service for long-term care patients requiring an orthopaedic consultation.

A cross-sectional study was used to assess TeleMSK from September 2018 to April 2019. 26 long-term care facilities participated in this study, which included 32 long-term care patients assessed via TeleMSK and 27 telemedicine liaisons. Telemedicine Satisfaction Scale (TeSS) and the Telemedicine Usability Questionnaire (TUQ) surveys were used to evaluate the usefulness of the TeleMSK program.

Patients and families rated voice (64.3%) and visual (71.4%) quality of TeleMSK to be excellent as well as the length of consultation (92.9%). 78.6% participants rated explanations from physicians to be excellent, 92.9% of the participants rated the carefulness, skillfulness, respect, and sensitivity of the attending physician to be excellent (85.7%). Patients felt privacy and confidentiality was maintained and respected throughout the consultation. The majority of telemedicine liaisons agreed that TeleMSK improved accessibility and productivity of consultations and 81.5% of the telemedicine liaisons strongly agreed that they would use TeleMSK again in the future.

TeleMSK allowed for accessible, timely orthopaedic consultations without compromising the quality of patient care. Patients, families, and telemedicine liaisons rated their experience and use of TeleMSK as excellent. Barriers to healthcare are important issues to be addressed in the long term care population. This can be conducted efficiently and effectively with Telemedicine.


P. Beauchamp-Chalifour E. Belzile V. Langevin R. Michael N. Gaudreau M. Lapierre-Fortin L. Landry N. Normandeau J. Veillette M. Bouchard R. Picard D. Lebel-Bernier S. Pelet

Elderly patients undergoing surgery for a hip fracture are at risk of thromboembolic events (TEV). The risk of TEV is now rare due to thromboprophylaxis. However, hip fracture treatment has evolved over the last decade. The risk of TEV may have been modified. The objective of this study was to determine the risk of symptomatic TEV following surgery for a hip fracture, in an elderly population.

Retrospective cohort study of all patients > 65 years old undergoing surgery for a femoral neck or intertrochanteric hip fracture in two academic centers, between January 1st 2008 and January 1st 2019. The follow-up was fixed at 3 months. The cumulated risk of thromboembolic events was calculated using the Kaplan-Meier estimator and a predictive logistic regression model was used to determine risk factors.

3265 patients were eligible for analysis. The mean age was 83.3 ±8.1 years old and 75.6% of patients were female. The mortality was 7.55% (N=112) at 3 months. 98.53% of this cohort received thromboprophylaxis. The cumulated risk for a thromboembolic event was 3.55% at 1 month and 6.41% at 3 months (N=99). There were 9 fatal pulmonary embolisms. 89.19% thromboembolic events occurred within 20 days following surgery. Chronic obstructive pulmonary disease (odds ratio 1.909 [1.179–3.089]), renal failure (odds ratio 1.896 [1.172–3.066]) and the use of a bridge between different types of anticoagulant (odds ratio 2.793 [1.057–7.384]) were associated with TEV. The risk of bleeding was 5.67% at 1 month and 9.38% at 3 months (N=142). 77% of bleeding events were hematomas.

The risk of thromboembolic events is higher than expected in a population treated for this condition. Most thromboembolic events occur shortly following surgery. The risk of bleeding is high and most of them are hematomas. Future research could focus on the management of thromboprophylaxis in elderly patients undergoing surgery for a hip fracture.


C. Prada S. Bzovsky S. Tanner F. Marcano-Fernandez K. Jeray E.H. Schemitsch M. Bhandari B. Petrisor S. Sprague

Many studies report the incidence and prevalence of surgical site infections (SSIs) following open fractures; however, there is limited information on the treatment and subsequent outcomes of superficial SSIs in open fracture patients. There is also a lack of clinical studies describing the prognostic factors that are associated with failure of antibiotic treatment (non-operative) for superficial SSI. To address this gap, we used data from the FLOW (Fluid Lavage in Open Fracture Wounds) trial to determine how successful antibiotic treatment was for superficial SSIs and to identify prognostic factors that could be predictive of antibiotic treatment failure.

This is a secondary analysis of the FLOW trial dataset. The FLOW trial included 2,445 operatively managed open fracture patients. FLOW participants who had a non-operatively managed superficial SSI diagnosed in the 12 months post-fracture were included in this analysis. Participants were grouped into two categories: 1) participants whose superficial SSI resolved with antibiotics alone and 2) participants whose SSI did not resolve with antibiotics alone (defined as requiring surgical management or SSI being unresolved at final follow-up (12-months post-fracture for the FLOW trial)). Antibiotic treatment success and the date when this occurred was defined by the treating surgeon. A logistic binary regression analysis was conducted to identify factors associated with superficial SSI antibiotic success. Based on biologic rationale and previous literature, a priori we identified 13 (corresponding to 14 levels) potential factors to be included in the regression model.

Superficial SSIs were diagnosed in168 participants within 12 months of their fracture. Of these, 139 (82.7%) had their superficial SSI treated with antibiotics alone. The antibiotic treatment was successful in resolving the superficial SSI in 97 participants (69.8%) and unsuccessful in resolving the SSI in 42 participants (30.2%). We found that superficial SSIs that were diagnosed later in follow-up were associated with failure of treatment with antibiotic alone (Odds ratio 1.05 for every week in diagnosis delay, 95% Confidence Interval 1.004–1.099; p=0.03). Age, sex, fracture severity, fracture pattern, wound size, time from injury to initial surgical irrigation and debridement were not associated with antibiotic treatment failure.

Our secondary analysis of prospectively collected FLOW data found antibiotics alone resolved superficial SSIs in 69.8% of patients diagnosed with superficial SSIs. We also found that superficial SSIs that were diagnosed earlier in follow-up were associated with successful treatment with antibiotics alone. This suggests that if superficial SSIs are diagnosed and treated promptly, there is a higher probability that they will resolve with antibiotic treatment.


P. Schneider J. Thoren D. Cushnie C. Del Balso C. Tieszer D.W. Sanders

Flexible fixation techniques combined with anatomic (open) syndesmosis reduction have demonstrated improved functional outcomes and rates of malreduction. Suture-button devices allow physiologic motion of the syndesmosis without need for implant removal, which may lower the risk of recurrent syndesmotic diastasis. There is limited longer-term assessment of the maintenance of reduction between static and flexible syndesmotic fixation using bilateral ankle CT evaluation.

This is an a priori planned subgroup analysis of a multi-centre, randomized clinical trial comparing static syndesmosis fixation (two 3.5 mm screws) with flexible fixation (single knotless Tightrope) for patients with AO- OTA 44-C injuries. Patients who completed bilateral ankle CT scans at 3- and 12-month follow-up were included. The primary outcome measure was syndesmotic malreduction based on bilateral ankle CT scans, using the uninjured, contralateral ankle as a control. Anterior (ASD), middle (MSD), and posterior (PSD) syndesmosis distance were calculated to measure syndesmosis reduction. Secondary outcomes included re-operation, adverse events and functional outcomes including the EQ5D, Olerud-Molander Ankle Score (OM), Foot and Ankle Disability Index (FADI), and Work Productivity Activity Impairment Questionnaire (WPAI). Paired samples t-tests were used to compare injured to control ankles (R, v 3.5.1).

42 patients (24 Group S, 18 Group T) were included. ASD for Group T was 5.22mm (95%CI 4.69–5.77) at 3 months compared to 4.26mm (95%CI 3.82–4.71; p=0.007) in controls and 5.38mm (95%CI 4.72–6.04) at 12 months compared to 4.44mm (95%CI 3.73–5.16; p=0.048) in controls. ASD for Group S was 4.63mm (95%CI 4.17– 5.10) at 3 months compared to 4.67mm (95%CI 4.24–5.10; p=0.61) in controls, but significantly increased to 5.73mm (95%CI 4.81–6.66) at 12 months compared to 4.65mm (95%CI 4.15–5.15; p=0.04) in controls. MSD results were similar; Group T had a larger MSD than control ankles at 3 months (p=0.03) and 12 months (p=0.01), while the MSD in Group S was not different at 3 months (p=0.80) but increased at 12 months (p=<0.01). 88% (21/24) of Group S had broken or removed screws by 12 months. Unplanned re-operation was 15% in Group S and 4% in Group T (p=0.02), with an overall re-operation rate of 30% in Group S. There was no significant difference between treatment groups for EQ-5D, OM, FADI or WPAI at 3- or 12-month follow-up.

Tightrope fixation resulted in greater diastasis of the ASD and MSD compared to contralateral, uninjured ankles at 3- and 12-months post-fixation. Group S initially had syndesmotic reduction similar to control ankles, but between 3- and 12-months post-fixation, there was significantly increased syndesmosis diastasis compared to controls. The majority of Group S (88%) had either broken screws or scheduled screw removal, which may explain the increased tibio-fibular diastasis seen at 12-months.


E. Sanders J. Dobransky A. Finless A. Adamczyk G. Wilkin A.S. Liew W. Gofton S. Papp P. Beaulé G. Grammatopoulos

Management of acetabular fractures in the elderly population remains somewhat controversial in regards to when to consider is open reduction internal fixation (ORIF) versus acute primary total hip. study aims to (1) describe outcome of this complex problem and investigate predictors of successful outcome.

This retrospective study analyzes all acetabular fractures in patients over the age of 60, managed by ORIF at a tertiary trauma care centre between 2007 and 2018 with a minimum follow up of one year. Of the 117 patients reviewed, 85 patients undergoing ORIF for treatment of their acetabular fracture were included in the analysis. The remainder were excluded based management option including acute ORIF with THA (n=10), two-stage ORIF (n=2), external fixator only (n=1), acute THA (n=1), and conservative management (n=1). The remainder were excluded based on inaccessible medical records (n=6), mislabelled diagnosis (n=6), associated femoral injuries (n=4), acetabular fracture following hemiarthroplasty (n=1). The mean age of the cohort is 70±7 years old with 74% (n=62) of patients being male. Data collected included: demographics, mechanism of injury, Charlson Comorbidity Index (CCI), ASA Grade, smoking status and reoperations. Pre-Operative Radiographs were analyzed to determine the Judet and Letournel fracture pattern, presence of comminution and posterior wall marginal impaction. Postoperative radiographs were used to determine Matta Grade of Reduction. Outcome measures included morbidity-, mortality- rates, joint survival, radiographic evidence of osteoarthritis and patient reported outcome measures (PROMs) using the Oxford Hip Score (OHS) at follow-up. A poor outcome in ORIF was defined as one of the following: 1) conversion to THA or 2) the presence of radiographic OA, combined with an OHS less than 34 (findings consistent with a hip that would benefit from a hip replacement). The data was analyzed step-wise to create a regression model predictive of outcome following ORIF.

Following ORIF, 31% (n=26) of the cohort had anatomic reduction, while 64% (n=54) had imperfect or poor reduction. 4 patients did not have adequate postoperative radiographs to assess the reduction. 31 of 84 patients undergoing ORIF had a complication of which 22.6% (n=19) required reoperation. The most common reason being conversion to THA (n=14), which occurred an average of 1.6±1.9 years post-ORIF. The remainder required reoperation for infection (n=5). Including those converted to THA, 43% (n=36) developed radiographic OA following acetabular fracture management. The mean OHS in patients undergoing ORIF was 36 ± 10; 13(16%) had an OHS less than 34. The results of the logistic regression demonstrate that Matta grade of reduction (p=0.017), to be predictive of a poor outcome in acetabular fracture management. With non-anatomic alignment following fixation, patients had a 3 times greater risk of a poor outcome. No other variables were found to be predictive of ORIF outcome.

The ability to achieve anatomic reduction of fracture fragments as determined by the Matta grade, is predictive of the ability to retain the native hip with acceptable outcome following acetabular fracture in the elderly. Further research must be conducted to determine predictors of adequate reduction in order to identify candidates for ORIF.


N. Dehghan A. Nauth E.H. Schemitsch M. Vicente R. Jenkinson H. Kreder M.D. McKee

Unstable chest wall injuries have high rates of mortality and morbidity. These injuries can lead to respiratory dysfunction, and are associated with high rates of pneumonia, sepsis, prolonged ICU stays, and increased health care costs. Numerous studies have demonstrated improved outcomes with surgical fixation compared to non-operative treatment. However, an adequately powered multi-centre randomized controlled study using modern fixation techniques has been lacking.

We present a multi-centred, prospective, randomized controlled trial comparing surgical fixation of acute, unstable chest wall injuries with the current standard of non-operative management. Patients aged 16–85 with a flail chest (3 or more consecutive, segmental, displaced rib fractures), or severe deformity of the chest wall, were recruited from multiple trauma centers across North America. Exclusion criteria included: severe pulmonary contusion, severe head trauma, randomization>72 hours from injury, inability to perform surgical fixation within 96 hours from injury (in those randomized to surgery), fractures of the floating ribs, or fractures adjacent to the spine not amendable to surgical fixation. Patients were seen in follow-up for one year. The primary outcome was days free from mechanical ventilation in the first 28 days following injury. Secondary outcomes were days in ICU, rates of pneumonia, sepsis, need for tracheostomy, mortality, general health outcomes, pulmonary function testing, and other complications of treatment. A sample size of 206 was required to detect a difference of 2 ventilator-free days between the two groups, using a 2-tailed alpha error of 0.05 and a power of 0.80.

A total of 207 patients were recruited from 15 sites across Canada and USA, from 2011–2018. Ninety-nine patients were randomized to non-operative treatment, and 108 were randomized to surgical fixation. Overall, the mean age was 53 years, and 75% of patients were male, with 25% females. The commonest mechanisms of injury were: motor vehicle collisions (34%), falls (20%), motorcycle collisions (14%), and pedestrian injuries (11%). The mean injury severity score (ISS) at admission was 26, and patients had a mean of 10 rib fractures. Eighty-nine percent of patients had pneumothorax, 76% had haemothorax, and 54% had pulmonary contusion. There were no differences between the two groups in terms of demographics. The final results will be available and presented at the COA meeting in Halifax.

This is the largest randomized controlled trial to date, comparing surgical fixation to non-operative treatment of unstable chest wall and flail chest injuries. The results of this study will shed light on the best treatment options for patients with such injuries, help understand outcomes, and guide treatment. The final results will be available and presented at the COA meeting in Halifax.


P. Beauchamp-Chalifour S. Pelet V. Belhumeur M. Angers-Goulet E. Belzile

Worldwide, it is expected that 6.3 million patients will sustain a hip fracture in 2050. Hemiarthroplasty is commonly practiced for displaced femoral neck fractures. The choice between unipolar (UH) or bipolar (BH) hemiarthroplasty is still controversial. The objective of this study was to assess the effect on hip function of BH compared to UH for a displaced femoral neck fracture in elderly patients.

We conducted a systematic review and meta-analysis of randomized controlled trials comparing BH to UH. Data sources were Medline, Embase, Cochrane Library and Web of Science. All data was pooled in Review Manager (RevMan) version 5.3 software. Selection of the studies included, data abstraction, data synthesis, risk of biais and quality of evidence evaluation was done independently by two authors. Our primary outcome was postoperative hip function. Secondary outcomes were health-related quality of life (HRQoL), acetabular erosion and postoperative complications.

13 randomized controlled trials (n=2256) were eligible for the meta-analysis. There was no difference in hip function scores (standardized mean difference of 0.33 [−0.09–0.75, n=864, I2= 87%,]). Patients with bipolar heads had higher Health-Related Quality of Life scores than patients with unipolar heads (mean difference in EQ-5D scores of 0.12 [0.04–0.19, n=550, I2= 44%]). The use of BH decreased the incidence of acetabular erosion (relative risk of 0.37 [0.17–0.83, n=525, I2= 0%]). There was no relative risk difference for mortality, dislocation, revision and infection.

Due to the high heterogeneity between the studies included, it is still unclear whether patients undergoing BH have better hip function than patients undergoing UH. Although, health-related quality of life (HRQoL) may be improved. Future research could be conducted to determine whether a BH offers a better quality of life than UH to geriatric patients undergoing surgery. More precise assessment scores could be developed to better evaluate postoperative outcomes.


M. Jodoin D. Rouleau C. Provost A. Bellemare E. Sandman S. Leduc L. De Beaumont

Acute pain is one of the most common symptoms shared among patients who have suffered from an orthopedic trauma such as an isolated upper limb fracture (IULF). Development of interventions with limited side effects aiming to prevent the installation of chronic pain is critical as persistent pain is associated with an increased risk of opioid dependence, medical complications, staggering financial burdens and diminished quality of life. Theta burst stimulation (TBS), a non-invasive magnetic brain stimulation technique with minimal side effects, has shown promising results in patients experiencing various types of chronic pain conditions as it precisely targets brain regions involved in pain processing. Surprisingly, its impact on acute pain has never been investigated. This study aims to assess longitudinal effects of a 10-day continuous TBS (cTBS) protocol applied in the acute phase of an IULF on key functional outcomes.

Patients with an IULF aged between 18 to 60 years old were recruited within 7 days post-accident at a Level I Trauma Center. Exclusion criteria included a history of brain injury, neurological disorders, musculoskeletal complications, and open fractures. In order to assess longitudinal changes, questionnaires measuring intensity and characteristics of pain (Numerical Rating Scale, NRS; McGill Pain Questionnaire, MPQ) as well as functional disability (DASH) were completed by all patients at three time points, namely prior to the start of the TBS program as well as 72 hours and 3 months post-intervention. Patients were randomly attributed to the active TBS protocol (active group) or to the placebo protocol (sham group). The stimulation site for each participant corresponded to the contralateral motor cortex of the injured arm.

Fifty patients were recruited (female: 24; age: 40.38 years old), of which 25 were in the active group and 25 were in the sham group. Both groups were equivalent based on age, sex, type of injury, and surgical procedures (p>0.05). The intervention protocol was introduced on average 6.18 days post-accident. In comparison to the sham group, the active group showed a significant decrease in pain intensity (NRS) at 72h (F=6.02; p=0.02) and 3-month (F=6.37; p=0.02) post-intervention. No group difference was found early-on (72h post) in regard to pain characteristics (MPQ; F=3.90; p=0.06) and functional disabilities (DASH; F=0.48; p= 0.49). At three-month post-intervention, the active group showed statistically significant improvement on the MPQ (F=5.02; p=0.04) and the DASH (F=5.88; p=0.02) compared to the placebo group. No complications related to the treatment were reported.

Results from this study show that patients who underwent active cTBS reported less pain and better functional states shortly after the end of the TBS protocol compared to sham patients and treatment effects were maintained at three months post-intervention. Given that acute pain intensity is an excellent predictor of chronic pain development, this safe technique available in numerous centers in Canada may help prevent chronic pain development when administered during the acute post-injury phase. Future studies should continue to investigate mechanisms involved to optimize this technique among the orthopedic trauma population and to reduce opioid consumption.


E.H. Schemitsch

Displaced femoral neck fractures can have devastating impacts on quality of life and patient function. Evidence for optimal surgical approach is far from definitive. The Hip Fracture Evaluation with Alternatives of Total Hip Arthroplasty versus Hemi-Arthroplasty (HEALTH) trial aimed to evaluate unplanned secondary procedures following total hip arthroplasty (THA) versus hemi-arthroplasty (HA) within two years of initial surgery for displaced femoral neck fractures. Secondary objectives evaluated differences in patient function, health-related quality of life, mortality, and hip-related complications HEALTH is a large randomized controlled trial that included 1,495 patients across 81 centers in 10 countries. Patients aged 50 years or older with displaced femoral neck fractures received either THA or HA. Participants were followed for 24 months post-fracture and a Central Adjudication Committee adjudicated fracture eligibility, technical placement of prosthesis, additional surgical procedures, hip-related complications, and mortality. The primary analyses were a Cox proportional hazards model with time to the primary study endpoint as the outcome and THA versus HA as the independent variable. Using multi-level linear models with three levels (centre, patient, and time), with patient and centre entered as random effects, the effect of THA versus HA on quality of life (Short Form-12 (SF-12) and EQ-5D), function (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), and mobility (Timed Up and Go Test (TUG)) were estimated separately.

The majority of patients were female (70.1%), 70 years of age or older (80.2%), and able to ambulate without the aid of an assistive device before their fracture (74.4%), and the injury in the majority of the patients was a subcapital femoral neck fracture (61.9%). The primary end point occurred in 57 of 718 patients (7.9%) who were randomly assigned to THA and 60 of 723 patients (8.3%) who were randomly assigned to HA (hazard ratio, 0.95; 95% confidence interval [CI], 0.64 to 1.40; p=0.79). Hip instability or dislocation occurred in 34 patients (4.7%) assigned to total hip arthroplasty and 17 patients (2.4%) assigned to hemi- arthroplasty (hazard ratio, 2.00; 99% CI, 0.97 to 4.09). Function, as measured with the total WOMAC total score, pain score, stiffness score, and function score, modestly favored THA over HA. Mortality was similar in the two treatment groups (14.3% among the patients assigned to THA and 13.1% among those assigned to HA, p=0.48). Serious adverse events occurred in 300 patients (41.8%) assigned to THA and in 265 patients (36.7%) assigned to HA.

Among independently ambulating patients with displaced femoral neck fractures, the incidence of secondary procedures did not differ significantly between patients who were randomly assigned to undergo THA and those who were assigned to undergo HA, and THA provided a clinically unimportant improvement over HA in function and quality of life over 24 months.


J.M. Lee J. Perera E. Rioux Trottier K. Tsoi S. Hopyan

Paediatric bone sarcomas around the knee are often amenable to either endoprosthetic reconstruction or rotationplasty. Cosmesis and durability dramatically distinguish these two options, although patient-reported functional satisfaction has been similar among survivors. However, the impact on oncological and surgical outcomes for these approaches has not been directly compared.

We retrospectively reviewed all wide resections for bone sarcoma of the distal femur or proximal tibia that were reconstructed either with an endoprosthesis or by rotationplasty at our institution between June 2004 and December 2014 with a minimum two year follow-up. Pertinent demographic information, surgical and oncological outcomes were reviewed. Survival analysis was performed using the Kaplan-Meier method with statistical significance set at p<0.05.

Thirty eight patients with primary sarcomas around the knee underwent wide resection and either endoprosthetic reconstruction (n=19) or rotationplasty (n=19). Groups were comparable in terms of demographic parameters and systemic tumour burden at presentation. We found that selection of endoprosthetic reconstruction versus rotationplasty did not impact overall survival for the entire patient cohort but was significant in subgroup analysis. Two-year overall survival was 86.7% and 85.6% in the endoprosthesis and rotationplasty groups, respectively (p=0.33). When only patients with greater than 90% chemotherapy-induced necrosis were considered, overall survival was significantly better in the rotationplasty versus endoprosthesis groups (100% vs. 72.9% at two years, p=0.013). Similarly, while event-free survival was not affected by reconstruction method (60.2% vs. 73.3% at two years for endoprosthesis vs rotationplasty, p=0.27), there was a trend towards lower local recurrence in rotationplasty patients (p=0.07). When surgical outcomes were considered, a higher complication rate was seen in patients that received an endoprosthesis compared to those who underwent rotationplasty. Including all reasons for re-operation, 78.9% (n=15) of the endoprosthesis patients required a minimum of one additional surgery compared with only 26.3% (n=5) among rotationplasty patients (p=0.003). The most common reasons for re-operation in endoprosthesis patients were wound breakdown/infection (n=6), limb length discrepancy (n=6) and periprosthetic fracture (n=2). Excluding limb length equalisation procedures, the average time to re-operation in this patient population was 5.6 months (range 1 week to 23 months). Similarly, the most common reason for a secondary procedure in rotationplasty patients was wound breakdown/infection, although only two patients experienced this complication. Average time to re-operation in this group was 23.8 months (range 5 to 49 months).

Endoprosthetic reconstruction and rotationplasty are both viable limb-salvage options following wide resection of high-grade bony sarcomas located around the knee in the paediatric population. Endoprosthetic reconstruction is associated with a higher complication rate and may negatively impact local recurrence. Study of a larger number of patients is needed to determine whether the reconstructive choice affects survival.


A. Bozzo J. Deng R. Bhasin M. Deodat U. Abbas S. Wariach D. Axelrod K. Masrouha D. Wilson M. Ghert

Lung cancer is the most common cancer diagnosed, the leading cause of cancer-related deaths, and bone metastases occurs in 20–40% of lung cancer patients. They often present symptomatically with pain or skeletal related events (SREs), which are independently associated with decreased survival. Bone modifying agents (BMAs) such as Denosumab or bisphosphonates are routinely used, however no specific guidelines exist from the National Comprehensive Cancer Center or the European Society of Medical Oncologists. Perhaps preventing the formation of guidelines is the lack of a high-quality quantitative synthesis of randomized controlled trial (RCT) data to determine the optimal treatment for the patient important outcomes of 1) Overall survival (OS), 2) Time to SRE, 3) SRE incidence, and 4) Pain Resolution. The objective of this study was to perform the first systematic review and network meta-analysis (NMA) to assess the best BMA for treatment of metastatic lung cancer to bone.

We conducted our study in accordance to the PRISMA protocol. We performed a librarian assisted search of MEDLINE, PubMed, EMBASE, and Cochrane Library and Chinese databases including CNKI and Wanfang Data. We included studies that are RCTs reporting outcomes specifically for lung cancer patients treated with a bisphosphonate or Denosumab. Screening, data extraction, risk of bias and GRADE were performed in duplicate. The NMA was performed using a Bayesian probability model with R. Results are reported as relative risks, odds ratios or mean differences, and the I2 value is reported for heterogeneity. We assessed all included articles for risk of bias and applied the novel GRADE framework for NMAs to rate the quality of evidence supporting each outcome.

We included 132 RCTs comprising 11,161 patients with skeletal metastases from lung cancer. For OS, denosumab was ranked above zoledronic acid (ZA) and estimated to confer an average of 3.7 months (95%CI: −0.5 – 7.6) increased survival compared to untreated patients. For time to SRE, denosumab was ranked first with an average of 9.1 additional SRE-free months (95%CI: 4.0 – 14.0) compared to untreated patients, while ZA conferred an additional 4.8 SRE-free months (2.4 – 7.0). Patients treated with the combination of Ibandronate and systemic therapy were 2.3 times (95%CI: 1.7 – 3.2) more likely to obtain successful pain resolution, compared to untreated. Meta-regression showed no effect of heterogeneity length of follow-up or pain scales on the observed treatment effects. Heterogeneity in the network was considered moderate for overall survival and time to SRE, mild for SRE incidence, and low for pain resolution. While a generally high risk of bias was observed across studies, whether they were from Western or Chinese databases. The overall GRADE for the evidence underlying our results is High for Pain control and SRE incidence, and Moderate for OS and time to SRE.

This study represents the most comprehensive synthesis of the best available evidence guiding pharmacological treatment of bone metastases from lung cancer. Denosumab is ranked above ZA for both overall survival and time to SRE, but both treatments are superior to no treatment. ZA was first among all bisphosphonates assessed for odds of reducing SRE incidence, while the combination of Ibandronate and radionuclide therapy was most effective at significantly reducing pain from metastases. Clinicians and policy makers may use this synthesis of all available RCT data as support for the use of a BMA in MBD for lung cancer.


A. Aoude Z. Lim J. Perera I. Ibe A. Griffin K. Tsoi P. Ferguson J.S. Wunder

Benign aggressive tumors are common and can be debilitating for patients especially if they are in peri-articular regions or cause pathological fracture as is common for giant cell tumor of bone (GCT). Although GCT rarely metastasize, the literature reports many series with high rates of local recurrence, and evidence about which risk factors influence recurrence is lacking. This study aims to evaluate the recurrence rate and identify local recurrence risk factors by reviewing patient data from a single high-volume orthopedic oncology center.

A retrospective analysis of all patients treated for GCT at a tertiary orthopedic oncology center was conducted. In total 413 patients were treated for GCT between 1989 and 2017. Multiple patient and tumour characteristics were analysed to determine if they influenced local recurrence including: age, gender, anatomical site, Campanacci stage, soft tissue extension, presence of metastasis, pathologic fractures, and prior local recurrence. Additional variables that were analysed included type of treatment (en bloc resection or aggressive intralesional curettage) and use of local adjuvants. The main outcome parameters were local recurrence- free survival, metastasis-free survival and complications. Patients treated with Denosumab were excluded from analysis given its recently documented association with high rates of local recurrence.

“There were 63/413 local recurrences (15.3%) at a mean follow-up of 30.5 months. The metastatic rate was 2.2% at a mean 50.6 months follow-up and did not vary based on type of treatment. Overall complication rate of 14.3% was not related to treatment modality. Local recurrence was higher (p=0.019) following curettage (55/310; 17.7%) compared to resection (8/103; 7.8%) however, joint salvage was possible in 87% of patients (270/310) in the curettage group. Use of adjuvant therapy including liquid nitrogen, peroxide, phenol, water versus none did not show any effect on local recurrence rates (p= 0.104). Pathological fracture did not affect local recurrence rates regardless of treatment modality (p= 0.260). Local recurrence at presentation was present in 16.3% (58/356) patients and did not show any significance for further local recurrence (p= 0.396). Gender was not associated with local recurrence (p=0.508) but younger patient age, below 20 years (p = 0.047) or below 30 years (p = 0.015) was associated with higher local recurrence rates. GCT in distal radius demonstrated the highest rate of local recurrence at 31.6% compared to other sites, although this was not significant (p=0.098). In addition, Campanacci stage and soft tissue extension were not risk factors for recurrence.

The overall GCT local recurrence rate was 15.3%, but varied based on the type of resection: 17.7% following joint sparing curettage compared to 7.8% following resection. Local recurrence was also higher with younger patient age (30 years or less) and in distal radius lesions. In addition, neither Campanacci stage, soft tissue extension or presence of a pathologic fracture affected local recurrence. Most patients with GCT can undergo successful curettage and joint sparing, while only a minority require resection +/− prosthetic reconstruction. Even in the presence of soft tissue extension or a pathologic fracture, most joints can be salvaged with curettage.


J. Perera I. Ibe A. Aoude A. Griffin P. Ferguson J.S. Wunder K. Tsoi

Myxoid or Myxoid Round Cell liposarcoma (MLS) is a mesenchymal malignancy with adipocyte differentiation accounting for 15–20% of liposarcomas and 5% of all adult soft tissue sarcomas (STS). Like other STS, treatment of MLS is generally by wide surgical resection in conjunction with radiotherapy and this approach is associated with low rates of local recurrence [1]. However, most MLS are located between muscles so wide local excision(WLE) can be quite morbid with adverse functional results. MLS are known to be extremely sensitive to radiotherapy which has led to development of treatment protocols utilizing neoadjuvant radiation. Given the radiosensitivity of MLS, we hypothesize that resection with marginal margins (1mm) does not result in higher rates of local recurrence or disease-free survival if performed following pre-operative radiotherapy.

We identified all patients with localized MLS who underwent preoperative radiation and surgical resection between January 2000 and January 2018 from a prospectively collected sarcoma database. We calculated the ellipsoid tumour volume(ETV=h x w x d x ()) at diagnosis and after radiation, and documented the necrosis percentage of the tumour and margin status following resection based on histological analysis [2]. Marginal resection was identified by the operative report describing no or only very minimal resection of muscle surrounding the tumour, and a negative surgical margin 0.1cm/1mm as defined histologically. In comparison, WLE was defined if the operative note described an attempt to remove the tumour with a cuff of surrounding muscle, and the final histology reported a negative margin 0.1cm/1mm which included skeletal muscle. The third group for analysis included patients with positive resection margins.

There were 91 patients with MLS of mean age 48 years (range 18–88) with 69% male and 31% female. The mean pre-radiotherapy ETV was 507cm3(16.1cm3 to 6961cm3) and decreased to 361cm3(8.7cm3 to 5695cm3) following radiation, with an average percentage reduction in ETV of −45%(+129%to-99%). Mean patient follow-up was 7.3 years (0.2–18) with no differences between margin groups(p=0.284). Only 10(11%) patients had positive margins, of which 43(47%) underwent marginal resection and 38(42%) WLE. Overall the mean necrosis as measured histologically following preoperative radiation was 69% (range 0–100%) with no differences between the 3 resection groups(p-0.151). Similarly, there was no significant difference in reduction in mean ETV between the three resection groups(p=0.311), there was no significant difference between the three treatment groups in 5-year LR-free survival (p=0.469), metastasis-free survival (p=0.841) or overall survival (p=0.873).

Most patients with MLS experienced significant reduction in tumour size and necrosis following preoperative radiation. We found no differences in the risk of local recurrence or survival based on the type of surgical approach for patients with MLS. Based on these results, we conclude that MLS can be safely removed by marginal resection following preoperative radiotherapy with high rates of local tumour control. Even following a positive margin resection, local recurrence remains uncommon after preoperative radiation. A marginal surgical approach for patients with MLS reduces the need for major muscle resection and is associated with improved functional outcomes with less complications.


K. Marritt K.M. Hildebrand A. Singla K. Hildebrand B. Yipp F. Jirik M. Monument

Soft tissue sarcomas (STS) are rare, aggressive malignancies derived from connective tissues such as muscle and fat. Undifferentiated pleomorphic sarcoma (UPS) is one of the most common STS in adults. UPS is an aggressive, highly metastatic sarcoma, and is resistant to chemotherapy. New therapies for UPS are desperately needed. STS have an immune desert tumour immune microenvironment (TIME), characterized by a paucity of tumour infiltrating lymphocytes and subsequent resistance to immunotherapies such as immune checkpoint inhibitors. Strategies capable of creating an immune-rich, inflamed TIME may improve immunotherapy efficacies for sarcoma. Activation of the STING (stimulator of interferon genes) receptor can induce potent innate and adaptive immune responses within immunogenic solid tumours. However, this approach has never been attempted in immune-inert sarcomas.

Purpose: To determine the therapeutic anti-tumour effects of STING activation in UPS tumours.

We have developed an inducible, immune-competent mouse model of UPS. We evaluated intra-tumoural injection of the murine STING receptor agonist, DMXAA, into UPS-bearing immune-competent mice. DMXAA was injected into palpable UPS tumours of the hindlimb. Tumour volume and bioluminescence imaging was recorded bi-weekly. DMXAA treated UPS tumours were also evaluated for necrosis and immune infiltration at defined time points.

UPS tumours developed necrosis and lymphocytic infiltration 72 hours after DMXAA treatment. A single intra-tumoural dose of DMXAA into UPS tumours resulted in durable cure in 50% of mice. All survivors rejected a re-challenge of the UPS tumours in both the contralateral hindlimb and lung, suggesting adaptive immunity. The therapeutic effects of DMXAA were mitigated in lymphocyte deficient Rag2 knockout mice.

STING therapy is a promising immunotherapeutic opportunity for immune-inert sarcomas. Our data warrants further preclinical investigations in other sarcoma models and in combination with other immune-based therapies.


J. Perera A. Atinga I. Ibe A. Aoude L. White D. Howarth A. Griffin K. Tsoi P. Ferguson J.S. Wunder

Myxofibrosarcoma (MFS) is the second most common subtype of soft tissue sarcoma (STS) and is associated with a high rate of local recurrence after resection. These tumours frequently present with peri-lesional edema, termed “tumour tails” on staging MRI scans [1]. Tumour tails(TT) may contain satellite neoplastic cells or can represent benign reactive edema. There are no clear radiological features to distinguish malignant from reactive peri-lesional edema which limits accurate surgical planning, resulting in either high rates of inadvertently positive resection margins and local recurrences or overly-aggressive resections which negatively impact function and increase morbidity [2]. The objective of this pilot study was to prospectively study a cohort of MFS patients with TTs in an attempt to identify radiological features that predict which type of edema is malignant and requires resection together with the main tumour mass.

Patients diagnosed with MFS on biopsy at an orthopaedic oncology referral centre between January 1-December 31 2018 who also had TTs on staging MRI scans were prospectively recruited for the study. Tumours were treated with wide surgical excision, including the TTs, and (neo)adjuvant radiotherapy as per institutional protocol. Staging MRI scans were reviewed in a blinded fashion by two musculoskeletal radiologists to distinguish malignant from reactive TTs. The main tumour mass underwent standard histological evaluation while the regions encompassing the TTs were photographed and sectioned into grids. Each tissue section was examined histologically for the presence of satellite neoplastic cells based on morphological criteria. Radiological and histological findings were compared.

Six patients met the inclusion criteria and underwent analysis. All tumours were located in the extremities and were deep to fascia. Mean age at presentation was 67 years (range 51 – 85), with a male:female ratio of 4:2. All patients received radiotherapy (50 Gy), either pre- (n=4) or post-operatively (n=2) based on multidisciplinary tumor board discussion or enrolment in a prospective clinical trial. Radiologically, TTs were labelled as malignant in four patients (66.7%) and as benign TTs in two others. The tails were recognised to be malignant due to the differing signal characteristics to reactive edema on mixed MRI sequences. The radiological evaluation correlated exactly with histological analysis, as satellite neoplastic cells were identified microscopically in the same four cases in which the TTs were designated to be malignant by MRI (specificity&sensitivity=100%). Surgical resection margins were microscopically positive in 50% of cases in the TTs themselves, and 75% of cases in which TTs were designated as malignant on staging MRI.

“The malignant nature of peri-lesional edema in MFS, also known as the TT, was accurately predicted in this small pilot study based on specific radiological features which correlated exactly with histologic identification of isolated tumor cells. These findings validate development of a larger prospective study to recruit additional patients with tumor tails beyond just MFS, in order to more robustly study the correlation between the MRI appearance and histological distribution of satellite sarcoma cells in peri-lesional edema in STS. We are already recruiting to this expanded radiological-histological investigation including evaluation of additional novel MRI sequences.


F. AlFayyadh H. Al Farii L. Farahdel R. Turcotte A. Frazer

The aim was to analyze the efficacy of zoledronic acid (ZA) versus denosumab in the prevention of pathological fractures in patients with bone metastases from advanced cancers by evaluating all available randomized controlled trials (RCTs) on this subject.

A systematic search of electronic databases (PubMed and MEDLINE) was performed to identify all published RCTs comparing zoledronic acid with denosumab in prevention of pathological fractures in bone metastases. Risk of bias of the studies was assessed. The primary outcomes evaluated were pathological fractures.

Four RCTs (7320 patients) were included. Denosumab was superior to ZA in reducing the likelihood of pathological fractures, when all tumour types were combined (OR 0.86, 95% CI [0.74, 0.99], p = 0.04). Denosumab was not significantly favoured over ZA in endodermal origin (breast and prostate) (OR 0.85, 95% CI [0.68, 1.05], p = 0.13) and mesodermal origin tumours (solid tumours and MM) (OR 0.87, 95% CI [0.71, 1.06], p = 0.16).

Denosumab significantly reduces the likelihood of pathological fractures in comparison to ZA in patients with bone metastases. When pathological fractures were grouped by tumour origin (endodermal or mesodermal), there was no significant difference between denosumab and ZA. Further long-term studies are needed to confirm the effectiveness of these treatment regimens.


A. Bozzo H. Seow G. Pond M. Ghert

Population-based studies from the United States have reported that sarcoma patients living in rural areas or belonging to lower socioeconomic classes experience worse overall survival; however, the evidence is not clear for universal healthcare systems where financial resources should theoretically not affect access to standard of care. The purpose of this study was to determine the survival outcomes of soft-tissue sarcoma (STS) patients treated in Ontario, Canada over 23 years and determine if the patient's geographic location or income quintile are associated with survival.

We performed a population-based cohort study using linked administrative databases of patients diagnosed with STS between 1993 – 2015. The Kaplan-Meier method was used to estimate 2, 5, 10, 15 and 20-year survival stratified by age, stage and location of tumor. We estimated survival outcomes based on the patient's geographic location and income quintile. The Log-Rank test was used to detect significant differences between groups. If groups were significantly different, a Cox proportional hazards model was used to test for interaction effects with other patient variables.

We identified 8,896 patients with biopsy-confirmed STS during the 23-year study period. Overall survival following STS diagnosis was 70% at 2 years, 59% at 5 years, 50% at 10 years, 43% at 15 years, and 38% at 20 years. Living in a rural location (p=0.0028) and belonging to the lowest income quintile (p<0.0001) were independently associated with lower overall survival following STS diagnosis. These findings were robust to tests of interaction with each other, age, gender, location of tumor and stage of disease.

This population-based cohort study of 8,896 STS patients treated in Ontario, Canada over 23 years reveals that patients living in a rural area and belonging to the lowest income quintile are at risk for decreased survival following STS diagnosis. We extend previous STS survival reporting by providing 15 and 20-year survival outcomes stratified by age, stage, and tumor location.


K. Mate K. Goulding U. Košir A. Tsimicalis R. Turcotte C. Freeman T. Alcindor N. Mayo

The patient's subjective experience of disease is an increasing focus in health care delivery. Health-related quality of life (HRQoL) is defined as a “functional effect of a medical condition and its consequent treatment”; it is both self-reported and multi-dimensional. While functional outcome is well researched among the soft tissue sarcoma (STS) population, few studies have focused on HRQoL, which gives a broader understanding of the psychological, somatic, social and physical toll of cancer and its treatment from the patient's viewpoint. The biologic and anatomic heterogeneity of sarcomas are considerable, just as the treatments are diverse, we surmise that the indicators of patient HRQoL differ and are not captured in existing generic HRQoL tools for cancer. The study objectives were to explore the domains of HRQoL and functioning in adult patients diagnosed with extremity STS from the patient's perspective from active care through survivorship through qualitative inquiry, so as to form the basis for the development of a patient-derived, sarcoma-specific, preference based HRQoL tool.

Study design is a sequential exploratory mixed methods study of patient experience in localized or metastatic adult extremity STS (2007 and 2017). The study was conducted at a high-volume sarcoma centre. Qualitative descriptive design was grounded in an integrated knowledge translation approach and aimed at identifying HRQoL domains through in-person and electronic focus groups, and individual semi-structured interviews in both English and French (N=28). The interview guide topics were selected based on existing knowledge about PROs and HRQoL life, including (a) impact of diagnosis on employment or acquisition of academic/vocational skills; (b) physical and psychological functioning; (c) symptom burden; (d) treatment preferences; (e) knowledge of and use of existing resources; (f) impact on family time and resources; and (g) overall experience. Data was analyzed using inductive thematic networks approach using the qualitative software N-Vivo 12. Codes were generated by 2 independent qualitative experts capturing key concepts of HRQoL that is impacted by STS. Basic themes were clustered into organizing themes, and merged into global domains. Attention was paid to deviant cases and within-group dynamics during focus group discussion analysis. Discrepancies or inconsistencies in coding were resolved in consensus meetings. Final sample size was determined when data saturation was reached and no new themes emerged. Qualitative reduction of identified items to reach a consensus framework was facilitated by a moderator during multi-disciplinary panel meetings comprised of sarcoma experts, patient partners, allied health staff and other stakeholders.

Twenty-nine patients with biopsy-proven localized or metastatic STS of the extremity participated (69% lower extremity STS; mean age 56 years, 25% with local recurrence, 21% metastatic, 18% amputation). Inductive thematic network analysis revealed five function-related domains HRQoL for patients with STS. The functional domains were mapped to the Wilson & Cleary Model and experience domains were mapped to the Picker Institute's Through Patient's Eyes model.

This is a critical step toward developing disease specific outcome measures. Patient-centered research is crucial to understanding the impact of surgery, adjuvant therapy and the associated complications for patients with extremity STS, and thereby improving the quality of care provision. This study offers a unique perspective on what domains and sub domains are most impactful on HRQoL and provides the basis for our on-going development of a disease-specific, preference-based HRQoL measure.


I. Ibe J. Perera A. Aoude A. Griffin J.S. Wunder P. Ferguson K. Tsoi

Ewing Sarcoma is the second most common primary bone sarcoma in young patients, however, there remains geographical variation in the treatment of these tumours. All patients receive neoadjuvant chemotherapy and, in most cases, the soft tissue mass diminishes significantly in volume. Controversy surrounds whether to then treat the pre- or post-chemotherapy tumour volume. Many centres advocate either (1) resection of the pre-chemotherapy volume or (2) treatment of the pre-chemotherapy volume with radiation followed by resection of the post-chemotherapy volume. These approaches increase both the short and long-term morbidity for this young patient population. In this study, we retrospectively reviewed our experience resecting only the post-chemotherapy volume without the use of (neo)adjuvant radiotherapy.

A retrospective analysis of all patients with Ewing Sarcoma treated at a tertiary orthopaedic oncology centre was conducted. All patients were treated as per the consensus opinion of the multidisciplinary tumour board. Demographic and oncological variables were collected from our institutional database. Presentation and re-staging MRI scans were reviewed to evaluate pre- and post-chemotherapy tumour volumes. Operative and pathology reports were utilized to determine the extent of the surgical resection. Outcome variables included local recurrence free-, metastasis free- and overall survival.

Sixty-five patients were identified in our institutional database of which 56 did not receive (neo)adjuvant radiotherapy. Median age at diagnosis was 24 years (range 13–64), 60% of patients were male and 67.6% of tumours were located in the appendicular skeleton. All 56 patients not treated with radiotherapy had resection of the post-chemotherapy tumour volume. There were 3 local recurrences in this group with a mean follow-up of 70.8 months (range 2 to 328). The median overall survival was 47 months and the mean of 70.8months.

The rate of local recurrence is comparable to reports in the literature in which patients had their entire pre-chemotherapy tumour volume treated by radiation and/or surgery. Similarly, two-year overall survival for our patient cohort is not significantly different from previous studies in which more aggressive local control measures were employed. Resecting the post-chemotherapy tumour volume in Ewing Sarcoma without the use of (neo)adjuvant radiotherapy does not appear to increase the risk of local recurrence or negatively impact overall survival. This approach should be studied further as it reduces the risk of short and long-term complications for this patient population.”


A. Gazendam A. Bozzo P. Schneider V. Giglio D. Wilson M. Ghert

Given the low prevalence of sarcoma, international cooperation is necessary to recruit sufficient numbers of patients for surgical trials. The PARITY (Prophylactic Antibiotic Regimens in Tumour Surgery) trial is the first international multicentre trial in orthopedic oncology and successfully achieved target enrollment of 600 patients across 12 countries. It is important to reflect upon the challenges encountered and experiences gained to inform future trials. The objective of this study is to describe recruitment patterns and examine the differences in enrollment across different PARITY sites and identify variables associated with varying levels of recruitment.

Data from this study was obtained from the PARITY trial Methods Centre and correspondence data. We performed descriptive statistics to demonstrate the recruitment patterns over time. We compared recruitment, time to set up, and time to enroll the first patient between North American and international sites, and sites that had dedicated research personnel. Two-tailed non-paired t-tests were performed to compare average monthly recruitment rates between groups with significance being set at alpha=0.05.

A total of 600 patients from 48 clinical sites and 12 countries were recruited from January 2013 through to October 2019. Average monthly enrollment increased every year of the study. There were 36 North American and 12 international sites. North American sites were able to set up significantly faster than international sites (19.3 vs. 28.3 months p=0.037). However, international sites had a significantly higher recruitment rate per month once active (0.2/month vs. 0.62/month, p=0.018). Of active sites, 40 (83%) had research support personnel and 8 (17%) sites did not. Sites with research personnel were able to reach ‘enrolment ready’ status significantly faster than sites without research support (19.6 vs. 30.7 months, p=0.032). However, there was no significant difference in recruitment rate per month once the sites began enrolling (0.28/month vs. 0.2/month, p=0.63). Trial sites that took longer than 1 year to recruit their first patient had 3x lower average recruitment rate compared to sites that were able to recruit their first patient within a year of being enrolment ready.

The PARITY trial is the first multicentre RCT in orthopaedic oncology. The PARITY investigators were able to increase the recruitment levels throughout the trial and generally avoid trial fatigue. This was a North American based trial which may explain the longer start up times internationally given the different regulatory bodies associated with drug-related trials. However, international sites should be considered critical as they were able to recruit significantly more patients per month once active. The absence of research support personnel should not preclude a site from inclusion. These sites took longer to setup but had no difference in monthly recruitment once active. This study will create a framework for identifying and targeting high yield sites for future randomized control trials within orthopaedic oncology to maximum recruitment and resource allocation. Data quality is another consideration that will be addressed in future analyses of the PARITY trial.


A. Lazarides J. Somarelli E. Altunel S. Rao S. Hoskinson S. Cheng C. Eward D. Hsu W. Eward

Osteosarcoma (OSA) is a rare, but disproportionately lethal cancer that predominantly affects children. Sadly, discovery of new therapies for OSA has largely been unsuccessful in the past 30 years; there is an urgent need to identify new treatments for OSA. Pet dogs with naturally-occurring OSA represent a unique comparative “model” to discover new treatments for OSA. Unlike humans, in which fewer than 1,000 cases of OSA occur each year, there are nearly 50,000 new cases each year of OSA in dogs. In addition, dogs have an intact immune system, a shared environment with humans, and more rapid progression of disease. Together these factors make dogs an important comparative model for new therapies for OSA. The purpose of this study was: 1) to validate this mouse-dog-human pipeline for drug discovery and 2) to validate CRM1 as a novel target for ostesoarcoma treatment.

We developed patient-derived cell lines and xenografts of OSA from both dogs and humans and applied these models to identify new therapies for OSA using high-throughput drug screens in vitro followed by in vivo validation. Whole exome sequencing was performed on the patient-derived models and original tumors to identify potential driver mutations.

A high-throughput screen in both dog and human OSA identified CRM1 inhibitors as effective at killing dog and human OSA patient-derived cell lines in vitro. In vivo, CRM1 inhibition led to significant tumor growth inhibition in patient-derived xenografts from dogs and humans. Western blotting demonstrated increased levels of CRM1 protein expression across nine different dog and human OSA cell lines compared to non-transformed human osteoblasts. CRM1 upregulation in OSA cells was further verified by immunofluorescence staining. Increased CRM1 expression was prognostic for poorer metastasis-free survival and poorer overall survival.

Our cross-species personalized medicine pipeline identified CRM1 as a potential therapeutic target to treat OSA in both dogs and humans. Future studies are focused on testing CRM1 inhibitors in canine clinical trials.


M. Hassani S. Jung R. Turcotte

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor with an intermediate tendency to metastasize, which is found in many different locations including head and neck, abdomen, chest cavity and extremities. Also, meningeal hemangiopericytoma (HPC) is considered an SFT which arises in the meningeal membranes. SFT family shows an undetermined biologic behavior varying from a silent indolent tumor to an aggressive malignant form; however, benign and malignant variants of SFT may have similar cytopathologic characteristics. In this study, we defined the factors correlated with SFT's aggressive behavior and patient's survival.

This is a retrospective study based on medical records of 85 patients who were suffering from SFT and had been treated at McGill University Health Centre (MUHC) between 1984 and 2017. We used multivariate logistic regression analysis to address any association between the variables including patient's demographics, tumor size, primary location of the tumor, pathological features, treatment methods and outcomes.

The median of the follow-up period was 60 months. The patient's age or gender had no association with tumor aggressive behavior or patient's survival. Anatomical origin of primary tumor had no strong correlation with the patient's disease related death (DRD); however, tumors originated from CNS showed more aggressive behavior. There was an association between tumor size more than 7 cm and distant metastasis (MT) (p= 0.03) and DRD (p=0.03). The tumor size also correlated with the 5-year disease-free survival (p=0.017). We had three histologic groups: 1- Benign SFT (30 cases), 2- cellular SFT or HPC (29 cases), 3- malignant SFT or anaplastic HPC (26 cases). Although univariate analysis demonstrates that patients suffering from cellular SFT and malignant SFT showed increased aggressive behavior of the tumor, multivariate analysis didn't verify the mentioned association. Patients with positive margins had increased odds ratio to experience tumor local recurrence (LR) (p= 0.05) and LR was correlated with DRD in our patients (p=0.006). Radiotherapy had no statistical association with LR, MT or DRD. Frequency of LR and MT in the study were 25.7% and 29.8% respectively. 5-year disease-free survival in our patients was 76%.

The size of SFT is the most correlative predictor of the tumor's aggressive behavior. The local recurrence of SFT is associated with disease related death; therefore, resection of the tumor with negative margins provides the highest chance of cure. In addition, a cellular SFT should be treated like a malignant variant of the tumor.


A. Jirovec A. Flaman B. Purgina F. Tzelepis H. Abdelbary J.S. Diallo J.M. Werier

The poor prognosis of patients with advanced bone and soft-tissue sarcoma has highlighted the necessity for new therapeutic approaches. T-cell based immunotherapies are a promising alternative to traditional cancer treatments due to their ability to target only malignant cells, leaving benign cells unharmed. The development of successful immunotherapy requires the identification of targetable immunogenic tumor antigens. Cancer-testis antigens (CTA) are a group of highly immunogenic tumor-associated proteins that have emerged as potential targets for CD8+ T-cell recognition. The goal of this study is to screen for CTA expression, HLA expression, and tumor T-cell infiltration in human dedifferentiated liposarcoma (DDLPS) and osteosarcoma (OS) to establish their immune profile and to identify targetable immunogenic antigens for T-cell based immunotherapy.

Human tissue micro-arrays composed of 78 cores of OS and 50 cores of DDLPS were obtained, along with matched control tissues from the same patients. IHC for the cancer testis antigens NY-ESO-1, MAGE-A3, and SSX2, was performed, and the staining results were scored by two authors based on maximal staining intensity on a scale of zero to three (absent=0, weak=1, moderate=2, or strong=3) and the percentage of tumor cells that stained. IHC for CD8 and CD3 was also performed, and T-cell tumor infiltration was defined as either brisk, nonbrisk, or absent, as described in melanoma literature. Concurrently, evaluation of 38 human DDLPS specimens and 10 healthy human fat specimens by the Nanostring nCounter platform is underway for identification of novel antigen targets and to establish the immune profile of DDLPS.

Immunohistochemical analysis of CTA expression showed considerable inter- and intra-tumoral heterogeneity. DDLPS showed relatively low expression of all CTAs tested, with only 22% of samples exhibiting MAGE-A3 and one sample each (3.1%) showing expression of SSX2 and NY-ESO-1 in low percentages of tumor cells. By contrast, in osteosarcoma, 74% of samples expressed MAGE-A3 and 68% expressed SSX, both with >80% of positive cases showing moderate to high expression. NY-ESO-1 was expressed in 41% of OS samples, predominantly at low levels. Brisk infiltration of CD8+ T cells was observed in over 70% of both sarcoma types tested. Furthermore, all sarcoma samples tested were positive for HLA expression.

To date, these results show promising expression of CTAs MAGE-A3 and SSX in OS, which may be used as targets in the future development of an immunotherapy for sarcoma. DDLPS shows relatively low expression, highlighting the need for more exploratory study with NanoString. The data generated throughout this project will provide insight into the immune profile of DDLPS.


A. Malik J. Alexander S. Khan T. Scharschmidt

The management of primary malignant bone tumors with metastatic disease at presentation remains a challenge. While surgical resection has been shown to improve overall survival among patients with non-metastatic malignant bone tumors, current evidence regarding the utility of surgery in improving overall survival in metastatic patients remains limited.

The 2004–2016 National Cancer Database (NCDB) was queried using International Classification of Diseases 3rd Edition (ICD-O-3) topographical codes to identify patients with primary malignant bone tumors of the extremities (C40.0-C40.3, C40.8 and C40.9) and/or pelvis (C41.4). Patients with malignant bone tumors of the axial skeleton (head/skull, trunk and spinal column) were excluded, as these cases are not routinely encountered and/or managed by orthopaedic oncologists. Histological codes were used to categorize the tumors into the following groups - osteosarcomas, chondrosarcomas, and Ewing sarcomas. Patients who were classified as stage I, II or III, based on American Joint Commission of Cancer (AJCC) guidelines, were excluded. Only patients with metastatic disease at presentation were included in the final study sample. The study sample was divided into two distinct groups – those who underwent surgical resection of the primary tumors vs. those who did not receive any surgery of the primary tumor. Kaplan-Meier survival analysis was used to report unadjusted 5-year overall survival rates between patients who underwent surgical resection of the primary tumor, compared to those who did not. Multi-variate Cox regression analyses were used to assess whether undergoing surgical resection of the primary tumor was associated with improved overall survival, after controlling for differences in baseline demographics, tumor characteristics (grade, location, histological type and tumor size), and treatment patterns (underwent metastatectomy of distal and/or regional sites, positive vs. negative surgical margins, use of radiation therapy and/or chemotherapy). Additional sensitivity analyses, stratified by histologic type for osteosarcomas, chondrosarcomas and Ewing sarcomas, were used to assess prognostic factors for overall survival.

A total of 2,288 primary malignant bone tumors (1,121 osteosarcomas, 345 chondrosarcomas, and 822 Ewing sarcomas) with metastatic disease at presentation were included – out of which 1,066 (46.0%) underwent a surgical resection of the primary site. Overall 5-year survival rates, on unadjusted Kaplan-Meier log-rank analysis, were significantly better for individuals who underwent surgical resection vs. those who did not receive any surgery (31.7% vs. 17.3%; p<0.001). After controlling for differences in baseline demographics, tumor characteristics and treatment patterns, undergoing surgical resection of primary site was associated with a reduced overall mortality (HR 0.42 [95% CI 0.36–0.49]; p<0.001). Undergoing metastectomy (HR 0.92 [95% CI 0.81–1.05]; p=0.235) was not associated with a significant improvement in overall survival. On stratified analysis, radiation therapy was associated with improved overall survival for Ewing Sarcoma (HR 0.71 [95% CI 0.57–0.88]; p=0.002), but not for osteosarcoma (HR 1.14 [95% CI 0.91–1.43]; p=0.643) or chondrosarcoma (HR 1.08 [95 % CI 0.78–1.50]; p=0.643). Chemotherapy was associated with improved overall survival for osteosarcoma (HR 0.50 [95% CI 0.39–0.64]; p<0.001) and chondrosarcoma (HR 0.62 [95% CI 0.45–0.85]; p=0.003), but not Ewing sarcoma (HR 0.79 [95% CI 0.46–1.35]; p=0.385).

Surgical resection of the primary site significantly improves overall survival for primary malignant bone tumors with metastatic disease at presentation. Physicians should strongly consider surgical resection of the primary tumor, with adjunct systemic and/or radiation therapy (dependent on tumor histology), in patients presenting with metastatic disease at presentation.


A. Lazarides E. Saltzman J. Visgauss S. Mithani W. Eward B. Brigman

For soft tissue sarcoma patients receiving preoperative radiation therapy, wound complications are common and potentially devastating; they may result in multiple subsequent surgeries and significant patient morbidity. The purpose of this study was to assess the feasibility of intraoperative indocyanine green fluorescent angiography (ICGA) as a predictor of wound complications in resections of irradiated soft tissue sarcoma of the extremities.

A consecutive series of patients of patients with soft tissue sarcoma of the extremities or pelvis who received neoadjuvant radiation and a subsequent radical resection received intraoperative ICGA with the SPY PHI device (Stryker Inc, Kalamazoo MI) at the time of closure. Three fellowship trained Orthopaedic Oncologic Surgeons were asked to prospectively predict likelihood of wound complications based on fluorescence. Retrospective analysis of fluorescence signal along multiple points of the wound length was performed and quantified. The primary endpoint was wound complication, defined as delayed wound healing or wound dehiscence, within 3 months of surgery. An a priori power analysis demonstrated that 5 patients were necessary to achieve statistical significance. Univariate and multivariate statistical analyses were performed to identify predictors of wound complications.

14 patients were consecutively imaged. The diagnosis was undifferentiated pleomorphic sarcoma in 9 (64.3%) of patients; 11 (78.6%) tumors were high grade. There were 6 patients with wound complications classified as “aseptic” in 5 cases and secondary to hematoma in 1 case. Using the ICGA, blinded surgeons correctly predicted wound complications in 75% of cases. In the area of wound complication, the mean % of maximal signal for wound complications was 49% during the inflow phase and 48% during the peak phase. The mean % maximal signal for peri-incisional tissue without wound complications was 77% during the inflow phase and 83% during the peak phase (p=0.003 and p<0.001). During the inflow phase, a mean ratio of normal of 0.62 maximized the area under the curve (AUC=0.90) for predicting wound complications with a sensitivity of 100% and specificity of 77.4%. During the peak phase, a mean ratio of normal of 0.55 maximized the area under the curve (AUC=0.95) for predicting wound complications with a sensitivity of 88.9% and a specificity 100%.

Intraoperative use of indocyanine green fluorescent angiography may help to predict wound complications in patients undergoing resection of preoperatively irradiated soft tissue sarcomas of the extremities and pelvis. Future studies are necessary to validate this technology in a prospective manner and to determine if interventions can be instituted to prevent predicted wound complications.