Aims

Dual-mobility (DM) components are increasingly used to prevent and treat dislocation after total hip arthroplasty (THA). Intraprosthetic dissociation (IPD) is a rare complication of DM that is believed to have decreased with contemporary implants. This study aimed to report incidence, treatment, and outcomes of contemporary DM IPD.

Macrophages (Mφ) are immune cells that play a crucial role in both innate and adaptive immunity as they are involved in a wide range of physiological and pathological processes. Depending on the microenvironment and signals present, Mφ can polarize into either M1 or M2 phenotypes, with M1 macrophages exhibiting pro-inflammatory and cytotoxic effects, while M2 macrophages having immunosuppressive and tissue repair properties. Macrophages have been shown to play key roles in the development and progression or inhibition of various diseases, including cancer. For example, macrophages can stimulate tumor progression by promoting immunosuppression, angiogenesis, invasion, and metastasis. This work aimed to investigate the effect of extracellular vesicles (EVs)-derived from polarized macrophages on an osteosarcoma cell line. Monocytes were extracted from buffy coats and cultured in RPMI medium with platelet lysate or M-CSF. After 6 days of seeding, Mφ were differentiated into M1 and M2 with INF-γ/LPS and IL-4/IL-13, respectively. The medium with M1 or M2 derived EVs was collected and EVs were isolated by differential centrifugation and size exclusion chromatography and its morphology and size were characterized with SEM and NTA, respectively. The presence of typical EVs markers (CD9, CD63) was assessed by Western Blot. Finally, EVs from M1 or M2-polarized Mφ were added onto osteosarcoma cell cultures and their effect on cell viability and cell cycle, proliferation, and gene expression was assessed. The EVs showed the typical shape, size and surface markers of EVs. Overall, we observed that osteosarcoma cells responded differentially to EVs isolated from the M1 and M2-polarized Mφ. In summary, the use of Mφ-derived EVs for the treatment of osteosarcoma and other cancers deserves further study as it could benefit from interesting traits of EVs such as low immunogenicity, nontoxicity, and ability to pass through tissue barriers.

Acknowledgements: Carlos III Health Institute and the European Social Fund for contract CP21/00136 and project PI22/01686.

Aim

Dalbavancin is a lipoglycopeptide with a half-life of 14 days (range 6.1 to 18.4), significantly longer than other antimicrobials, which avoids the need for daily antibiotic dosing. This multi-centre observational study aims to describe the use of dalbavancin to facilitate discharge in treating bone and joint infections.

Aim

The use of bone substitutes such as calcium sulfate (CaSO4) and hydroxyapatite with local antibiotics are crucial in the treatment of osteomyelitis. They allow the treatment of the dead space and locally provide large concentrations of antibiotics. However, it is unknown whether use of local vancomycin may elute and influence on vancomycin plasma levels. The aim of this study is to assess whether the addition of vancomycin to CaSO4 with hydroxyapatite may increase vancomycin plasma concentrations in in patients with osteomyelitis and therefore alter dosage adjustments.

While pre-soaking grafts in vancomycin has demonstrated to be effective in observational studies for anterior cruciate ligament reconstruction (ACLR) infection prevention, the economic benefit of the technique is uncertain. The primary aim of this study was to determine the cost-effectiveness of vancomycin pre-soaking during primary ACLR to prevent post-operative joint infections. The secondary aims of the study were to establish the breakeven cost-effectiveness threshold of the technique.

A Markov model was used to determine cost effectiveness and the incremental cost effectiveness ratio of additional vancomycin pre-soaking compared to intravenous antibiotic prophylaxis alone. A repeated meta-analysis of nine cohort studies (Level III evidence) was completed to determine the odds ratio of infection with vancomycin pre-soaking compared to intravenous antibiotics alone. Estimated costs and transitional probabilities for further surgery were obtained from the literature. Breakeven threshold analysis was performed.

The vancomycin soaking technique provides an expected cost saving of $600AUD per patient. There was an improvement in the quality-adjusted life years of 0.007 compared to intravenous antibiotic prophylaxis alone (4.297 versus 4.290). If the infection rate is below 0.023% with intravenous antibiotics alone or the additional intervention cost more than $1000AUD, the vancomycin wrap would no longer be cost-effective.

For $30AUD, the vancomycin soaking technique provides a $600AUD cost saving by both reducing the risk of ACLR related infection and economic burden of infection. Treating septic arthritis represents a mean cost per patient of 6 times compared to that of the primary surgery. There has been no previous cost-effectiveness study of the vancomycin wrap technique.

The vancomycin pre-soaking technique is a highly cost-effective method to prevent post-operative septic arthritis following primary ACLR.

Progressive collapsing foot deformity (PCFD) is a common condition with an estimated prevalence of 3.3% in women greater than 40 years. Progressive in nature, symptomatic flatfoot deformity can be a debilitating condition due to pain and limited physical function; it has been shown to have one of the poorest preoperative patient reported outcome scores in foot and ankle pathologies, second to ankle arthritis. Operative reconstruction of PCFD can be performed in a single-stage manner or through multiple stages. The purpose of this study is to compare costs for non-staged (NS) flatfoot reconstructions, which typically require longer hospital stays, with costs for staged (S) reconstructions, where patients usually do not require hospital admission. To our knowledge, the comparison between single-staged and multi-staged flatfoot reconstructions has not been previously done. This study will run in conjunction with one that compares rates of complications and reoperation, as well as patient reported outcomes on function and pain associated with S and NS flatfoot reconstruction. Overall, the goal is to optimize surgical management of PCFD, by addressing healthcare costs and patient outcomes.

At our academic centre with foot and ankle specialists, we selected one surgeon who primarily performs NS flatfoot reconstruction and another who primarily performs S procedures. Retrospective chart reviews of patients who have undergone either S or NS flatfoot reconstruction were performed from November 2011 to August 2021. Length of operating time, number of primary surgeries, length of hospital admission, and number of reoperations were recorded. Cost analysis was performed using local health authority patient rates for non residents as a proxy for health system costs. Rates of operating room per hour and hospital ward stay per diem in Canadian dollars were used. The analysis is currently ongoing.

72 feet from 66 patients were analyzed in the S group while 78 feet from 70 patients were analyzed in the NS group. The average age in the S and NS group are 49.64 +/− 1.76 and 57.23 +/− 1.68 years, respectively. The percentage of female patients in the S and NS group are 63.89% and 57.69%, respectively. All NS patients stayed in hospital post-operatively and the average length of stay for NS patients is 3.65 +/− 0.37 days. Only 10 patients from S group required hospital admission.

The average total operating room cost including all stages for S patients was $12,303.12 +/− $582.20. When including in-patient ward costs for patients who required admission from S group, the average cost for operating room and in-patient ward admission was $14,196.00 +/− $1,070.01 after flatfoot reconstruction.

The average in-patient ward admission cost for NS patients was $14,518.83 +/− $1,476.94 after flatfoot reconstruction. The cost analysis for total operating room costs for NS patients are currently ongoing. Statistical analysis comparing S to NS flatfoot reconstruction costs are pending.

Preliminary cost analysis suggests that multi-staged flatfoot reconstruction costs less than single-staged flatfoot reconstruction. Once full assessment is complete with statistical analysis, correlation with patient reported outcomes and complication rate can guide future PCFD surgical management.

Progressive collapsing foot deformity (PCFD) is a complex foot deformity with varying degrees of hindfoot valgus, forefoot abduction, forefoot varus, and collapse or hypermobility of the medial column. In its management, muscle and tendon balancing are important to address the deformity. Peroneus brevis is the primary evertor of the foot, and the strongest antagonist to the tibialis posterior. Moreover, peroneus longus is an important stabilizer of the medial column. To our knowledge, the role of peroneus brevis to peroneus longus tendon transfer in cases of PCFD has not been reported.

This study evaluates patient reported outcomes including pain scores and any associated surgical complications for patients with PCFD undergoing isolated peroneus brevis to longus tendon transfer and gastrocnemius recession.

Patients with symptomatic PCFD who had failed non-operative treatment, and underwent isolated soft tissue correction with peroneus brevis to longus tendon transfer and gastrocnemius recession were included. Procedures were performed by a single surgeon at a large University affiliated teaching hospital between January 1 2016 to March 31 2021. Patients younger than 18 years old, or undergoing surgical correction for PCFD which included osseous correction were excluded.

Patient demographics, medical comorbidities, procedures performed, and pre and post-operative patient related outcomes were collected via medical chart review and using the appropriate questionnaires.

Outcomes assessed included Visual Analogue Scale (VAS) for foot and ankle pain as well as sinus tarsi pain (0-10), patient reported outcomes on EQ-5D, and documented complications.

Statistical analysis was utilized to report change in VAS and EQ-5D outcomes using a paired t-test. Statistical significance was noted with p<0.05.

We analysed 43 feet in 39 adults who fulfilled the inclusion criteria. Mean age was 55.4 ± 14.5 years old. The patient reported outcome mean results and statistical analysis are shown in Table one below. Mean pre and post-operative foot and ankle VAS pain was 6.73, and 3.13 respectively with a mean difference of 3.6 (p<0.001, 95% CI 2.6, 4.6). Mean pre and post-operative sinus tarsi VAS pain was 6.03 and 3.88, respectively with a mean difference of 2.1 (p<0.001, 95% CI 0.9, 3.4). Mean pre and post-operative EQ-5D Pain scores were 2.19 and 1.83 respectively with a mean difference of 0.4 (p=0.008, 95% CI 0.1, 0.6). Mean follow up time was 18.8 ± 18.4 months.

Peroneus brevis to longus tendon transfer and gastrocnemius recession in the management of symptomatic progressive collapsing foot deformity significantly improved sinus tarsi and overall foot and ankle pain. Most EQ-5D scores improved, but did not reach statistically significant values with the exception of the pain score. This may have been limited by our cohort size. To our knowledge, this is the first report in the literature describing clinical results in the form of patient reported outcomes following treatment with this combination of isolated soft tissue procedures for the treatment of PCFD.

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

Aim

The treatment of fracture-related infections (FRI) focuses on obtaining fracture healing and eradicating infection to prevent osteomyelitis. Treatment guidelines include removal, exchange, or retention of the implants used according to the stability of the fracture and the time from the infection. Infection of a fracture in the process of healing with a stable fixation may be treated with implant retention, debridement, and antibiotics. Nonetheless, the retention of an intramedullary nail is a potential risk factor for failure, and it is recommended to exchange or remove the nail. This surgical approach implies additional life-threatening risks in elderly fragile hip fracture patients.

Our study aimed to analyze the results of implant retention for the treatment of infected nails in elderly hip fracture patients.

Introduction

Although total knee arthroplasty (TKA) is generally considered successful, 16–30% of patients are dissatisfied. There are multiple reasons for this, but some of the most frequent reasons for revision are instability and joint stiffness. A possible explanation for this is that the implant alignment is not optimized to ensure joint stability in the individual patient. In this work, we used an artificial neural network (ANN) to learn the relation between a given standard cruciate-retaining (CR) implant position and model-predicted post-operative knee kinematics. The final aim was to find a patient-specific implant alignment that will result in the estimated post-operative knee kinematics closest to the native knee.

Aims

To analyze the potential role of synovial fluid peptidase activity as a measure of disease burden and predictive biomarker of progression in knee osteoarthritis (KOA).

Introduction

Loosening of the baseplate is one of the most common causes of failure in Reverse Shoulder Arthroplasty. To allow osteo-integration to occur and thus provide long-term stability, initial screws fixation plays a pivotal role. In particular, tightening torque and force of nonlocking screws are two parameters that are considered to have a clear impact on implant stability, yet the relation is not fully understood. For this reason, this study aims to define an experimental set-up, to measure force and torque in artificial bone samples of different quality, in order to estimate ranges of optimal surgical values and give guidelines to maximize screw fixation and therefore initial implant stability.

3D cell culture studies more accurately represent the complex in vivo mechanical environment of human bone and are, thus, superior to 2D studies when testing the efficacy of osteoporosis therapies. As such, the objective of this study was to use a 3D model to investigate the effect of sclerostin antibodies. Sclerostin is a protein, which inhibits osteoblasts and is downregulated under mechanical stimulation. It is not yet known how expression of sclerostin mediates the site-specific and temporal changes in mineralisation. To address this, we developed a 3D cellular niche of MC3T3 osteoblasts encapsulated within gelatin and applied mechanical loading to the constructs using a custom-designed compression bioreactor system (0.5% strain at 0.5 Hz, 1 hr/day) (VizStim) under continuous perfusion of cell culture media. Osteoblasts were pretreated with estrogen for 14 days, followed by estrogen withdrawal (EW) to simulate postmenopausal conditions. 3D constructs were successfully fabricated and actin staining revealed the formation of dendritic cells under both static and stimulated conditions indicative of osteocyte-like cells. Under static conditions, estrogen treatment enhanced production of calcium by osteoblasts when compared to the same cells cultured under estrogen deficient conditions. Overall, preliminary results propose a link between mechanical stimulation, estrogen deficiency and mineral production by osteoblasts. Ongoing studies are comparing the static and stimulated groups after a longer culture period of 21 days using sclerostin antibodies. This research aims to deliver further understanding of the mechanical regulation of bone formation, and will inform novel approaches for regeneration of bone tissue and treatment of osteoporosis.

Introduction

Despite the demonstrated success of total knee arthroplasty (TKA) and higher rates of arthritis and disability from arthritis among minorities, these populations utilize TKA at lower rates than non-Hispanic white patients in the United States. In addition, women present for TKA with more advanced disease prior to TKA than their male counterparts. In order to explore potential reasons for this, we examined the relationship between race, gender, and pre-operative expectations on postoperative outcomes among patients undergoing TKA.

Objectives

Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the in vitro studies did not evaluate bacterial adhesion in the presence of eukaryotic cells, as stated by the ‘race for the surface’ theory. Moreover, the adherence of numerous clinical strains with different initial concentrations has not been studied.

Polyether ether ketone (PEEK) has been increasingly employed as biomaterials for trauma, orthopeadic, and spinal implants. However, concern has been raised about the inertness of PEEK which limits bone integration. In this study, we have coated PEEK with a functional material seeking to promote osteogenic differentiation of human mesenchymal stem cells (hMSC).

We have used spray drying to coat poly(ethyl acrylate) (PEA) as a coating on PEEK. This technique is simple, allows a range of controlled coating thicknesses (from hundred nm to a few um), cost effective and easily translatable to scaffolds or implant surfaces for existing or new orthopaedic applications. PEA induces the organisation of fibronectin (FN) into nanonetworks upon simple adsorption from protein solutions. These FN nanonetworks on PEA represent a microenvironment for efficient growth factor binding and presentation in very low but effective doses. In this study we show cell adhesion and stem cell differentiation towards an osteogenic lineages when bone morphogenetic protein 2 (BMP2) was adsorbed on these engineered PEEK/PEA/FN microenvironments in very low doses.

Overall, the developed functional coatings on PEEK has the potential to allow the translation of this material into orthopaedic applications.

Successfully treatment of acute shoulder arthroplasty infections strongly depends on the timing of treatment. The objective of this study is to determine the normalization curve of C-reactive protein (CRP) after shoulder arthroplasty

Prospective study including 63 patients undergoing shoulder arthroplasty (46 reverse shoulder arthroplasty (RSA) and 17 total shoulder (TSA)). Mean age 74.1 years old. 25 cuff deficient shoulders, 14 acute fractures, 19 primary gleno-humeral arthritis and 5 fracture sequel were included. Blood samples to determine CRP were obtained before surgery the day of surgery, 24 and 48 hours after surgery and then 6, 8 and 14 days after surgery (data of blood samples was determined based on a previous limited study). Co-morbidities that could interfere CRP were also recorded

Normal value of CRP before surgery (mean 1.28) slightly increases 24 hours after surgery (mean 3.92), reach maximum value at 48 hours after surgery (mean 6.91) and then slowly decreases to normalize at 14 days (6th day mean 3.80, 8th day 2.33 and 14th day 1.08). Normalization curve is not affected by age, diagnosis or type of arthroplasty

CRP after shoulder arthroplasty reaches maximum value at 48h and then slowly decreases to become normal at 14 days. Any deviation from this normalization curve may help in diagnosis and early treatment of acute shoulder arthroplasty infections

Summary Statement

Description of an original in vitro protocol for assessing combined bacteria and cell competitive adherence on the surface of biomaterials of medical interest

INTRODUCTION

Biomaterial-related infections are an important complication in orthopaedic surgery [1], and Staphylococcus sp. accounts for more than half of the prosthetic joint infection cases [2]. Adhesion of bacteria to biomaterial surfaces is a key step in pathogenesis of such infections [3]. Titanium alloys are widely used in orthopaedic implants because their biocompatibility [4]. Surface incorporation of ions with antimicrobial properties, like fluorine, is one strategy previously studied with good results [5].

We completed a retrospective case study of 66 consecutive isolated closed 5^th metacarpal neck fractures that presented to our Hospital between September 2009 and March 2010. Their management was established by referring to outpatient letters and A&E notes. The aim of the study was to establish if it would be more efficient and cost effective for these patients to be managed in A&E review clinic without compromising patient care.

Of these 66 patients, 56 were males and the mean age was 26 years (12–88 years). Four fractures were not followed up at our Trust, six did not attend their outpatient appointment, one did not require follow up.

Of the remaining 55, reviewed at a fracture clinic, all but two were managed conservatively, with 47% requiring one outpatient appointment only. The cost of a new patient Orthopaedic outpatient appointment is £180 with subsequent follow up appointments costing £80 per visit, in contrast to an A&E review clinic appointment at a cost of £60.

In view of the small percentage in need of surgical intervention: we highlight the possibility for these patients to be managed solely in the A&E department with a management plan made at the A&E review clinic with an option to refer patients if necessary, and the provision of management guidelines and care quality assurance measures.

This, we believe, would maintain care quality for these patients, improve efficiency of fracture clinics and decrease cost. We calculate that even if only all the patients that required one follow up appointment could have been managed by A&E alone then the saving to the local health commissioning body over a six month period from within our trust alone, would have been £3000, which across all trusts providing acute trauma services within the NHS would amount to a substantial saving nationwide.

Introduction: One of the more difficult questions in the management of posttraumatic osteomyelitis is the decision for removing or retaining infected hardware. We know that skeletal stabilization in posttraumatic osteomyelitis is necessary for controlling infection. However, in the presence of internal fixation, microorganisms are protected in a biofilm adherent to the implant surface. The decision to retain or remove infected implants is individualizated and depends on several factors: status of bone healing, stability provided by the hardware, fracture localization, and time since fracture fixation.

Material and Method: We used in our Hospital the algorithm proposed by Patzakis and Zalavras1 in 2005. The objective of our lecture is to define the decision to remove the implant with some case reports.

Conclusion: The management of infected hardware in patients with postraumatic osteomielitis in long bones is difficult and it is necessary to study each cases individualizated but it is necessary to have a guidelines.

We must remove the implant:

If the fracture has healed.