Introduction

Day stay surgery for anterior cruciate ligament (ACL) reconstructions is an increasingly common practice and has driven clinicians to come up with postoperative pain regimes that allow same day mobilisation and a safe and timely discharge. There is a paucity of literature surrounding the use of intraosseous (IO) ropivacaine used as a Bier's block to provide both intraoperative and postoperative analgesia in lower limb surgery.

Aims

Hip fracture is a common injury in the elderly. Recent studies in orthopaedic access have demonstrated inequities affecting Māori. This study aimed to compare the demographic differences between Māori and NZ Europeans with hip fractures, identify any deficiencies in initial, surgical and post op care and in outcomes.

Background

Anterior cruciate ligament (ACL) reconstruction with concomitant meniscal injury occurs frequently. Meniscal repair is associated with improved long-term outcomes compared to resection but is also associated with a higher reoperation rate. Knowledge of the risk factors for repair failure may be important in optimizing patient outcomes.

Aims

Using the Australian and New Zealand Hip Fracture Registry (ANZHFR) data, this study aimed to identify patient, fracture, and management factors associated with survival, mobility and residential status at 120 days. This will allow future interventions to target modifiable risk factors to improve the overall care of patients with hip fractures.

Introduction

Individuals with significant hip and knee trauma receive total knee (TKA) and total hip arthroplasty (THA) as definitive end-stage procedures. In Aotearoa, injury-related costs, including workers compensation, may be funded by ACC. With a steady increase of arthroplasty procedures in Aotearoa, we aim to understand the magnitude and characteristics of such procedures to inform future healthcare strategies.

Unicompartmental knee arthroplasty (UKA) has a higher risk of revision than total knee arthroplasty, particularly for low volume surgeons. The recent introduction of robotic-arm assisted systems has allowed for increased accuracy, however new systems typically have learning curves. The objective of this study was to determine the learning curve of a robotic-arm assisted system for UKA.

Methods A total of 152 consecutive robotic-arm assisted primary medial UKA were performed by five surgeons between 2017 and 2021. Operative times, implant positioning, reoperations and patient-reported outcome measures (PROMS; Oxford Knee Score, EuroQol-5D, and Forgotten Joint Score) were recorded.

There was a learning curve of 11 cases with the system that was associated with increased operative time (13 minutes, p<0.01) and improved insert sizing over time (p=0.03). There was no difference in implant survival (98.2%) between learning and proficiency phases (p = 0.15), and no difference in survivorship between ‘high’ and ‘low’ usage surgeons (p = 0.23) at 36 months. There were no differences in PROMS related to the learning curve. This suggested that the learning curve did not lead to early adverse effects in this patient cohort.

The introduction of a robotic-arm assisted UKA system led to learning curves for operative time and implant sizing, but there was no effect on patient outcomes at early follow- up. The short learning curve was independent of UKA usage and indicated that robotic-arm assisted UKA may be particularly useful for low-usage surgeons.

Unicompartmental knee arthroplasty (UKA) is associated with a higher risk of revision compared with total knee arthroplasty (TKA). The outcomes of knee arthroplasty are typically presented as implant survival or incidence of revision after a set number of years, which can be difficult for patients and clinicians to conceptualise. We aimed to calculate the ‘lifetime risk’ of revision for UKA as a more relatable estimate of risk projection over a patient's remaining lifetime, and make comparisons to TKA. All primary UKAS performed from 1999 to 2019 (n=13,481) captured by the New Zealand Joint Registry (NZJR) were included. The lifetime risk of revision was calculated and stratified by age, gender and American Society of Anesthesiologists (ASA) status. The lifetime risk of revision for UKA was highest in the youngest patients (46-50 years; 40.4%) and lowest in the oldest patients (86-90 years; 3.7%). Lifetime risk of revision was higher for females (range 4.3%-43.4% cf. males 2.9%-37.4%) and patients with higher ASA status (ASA 3-4 range 8.8%-41.2% cf. ASA 1 1.8%-29.8%), regardless of age. The lifetime risk of UKA was two-fold higher than TKA (ranging from 3.7%-40.4% UKA, 1.6%-22.4% TKA) across all age groups. Increased risk of revision in the younger patients was associated with aseptic loosening in both males and females, and pain in females. Periprosthetic joint infections (PJI) accounted for 4% of all UKA revisions, in contrast to 27% for TKA; risk of PJI was higher for males than females for both procedures. The lifetime risk of revision is a more meaningful measure of arthroplasty outcomes and can aid with patient counselling prior to UKA. Findings from this study show the increased lifetime risk of UKA revision for younger patients, females and those with higher ASA status.

Source of the study: University of Auckland, Auckland, New Zealand and University of Otago, Christchurch, New Zealand

The Oxford Knee Score (OKS) is a 12-item questionnaire used to track knee arthroplasty outcomes. Validation of such patient reported outcome measures is typically anchored to a single question based on patient ‘satisfaction’, however risk of subsequent revision surgery is also an important outcome measure. The OKS can predict subsequent revision risk within two years, however it is not known which item(s) are the strongest predictors. Our aim was to identify which questions were most relevant in the prediction of subsequent knee arthroplasty revision risk.

All primary TKAs (n=27,708) and UKAs (n=8,415) captured by the New Zealand Joint Registry between 1999 and 2019 with at least one OKS response at six months, five years or ten years post-surgery were included. Logistic regression and receiver operating characteristics (ROC) curves were used to assess prediction models at six months, five years and ten years.

Q1 ‘overall pain’ was the strongest predictor of revision within two years (TKA: 6 months, odds ratio (OR) 1.37; 5 years, OR 1.80; 10 years, OR 1.43; UKA: 6 months, OR 1.32; 5 years, OR 2.88; 10 years, OR 1.85; all p<0.05). A reduced model with just three questions (Q1, Q6 ‘limping when walking’, Q10 ‘knee giving way’) showed comparable or better diagnostic ability with the full OKS (area under the curve (AUC): TKA: 6 months, 0.77 vs. 0.76; 5 years, 0.78 vs. 0.75; 10 years, 0.76 vs. 0.73; UKA: 6 months, 0.80 vs. 0.78; 5 years: 0.81 vs. 0.77; 10 years, 0.80 vs. 0.77).

The three questions on overall knee pain, limping when walking, and knee ‘giving way’ were the strongest predictors of subsequent revision within two years. Attention to the responses for these three key questions during follow-up may allow for prompt identification of patients most at risk of revision.

Contemporary indications for unicompartmental knee replacement (UKR) include bone on bone radiographic changes in the medial compartment with relatively preserved lateral and patellofemoral compartments. The role of MRI in identifying candidates for UKR is commonplace. The aim of this study was to assess the relationship between radiographic and MRI pre-operative grade and outcome following UKR.

A retrospective analysis of medial UKR patients from 2017 to 2021. Inclusion criteria were medial UKR for osteoarthritis with pre-operative and post-operative Oxford Knee Scores (OKS), pre-operative radiographs and MRI.

89 patients were included. Whilst all patients had grade 4 ICRS scores on MRI, 36/89 patients had grade 3 KL radiographic scores in the medial compartment, 50/89 had grade 4 KL scores on the medial compartment. Grade 3 KL with grade 4 IRCS medial compartment patients had a mean OKS change of 17.22 (Sd 9.190) meanwhile Grade 4 KL had a mean change of 17.54 (SD 9.001), with no statistical difference in the OKS change score following UKR between these two groups (p=0.873). Medial bone oedema was present in all but one patient. Whilst lateral compartment MRI ICRS scores ranged from 1 to 4 there was no association with MRI score of the lateral compartment and subsequent change in oxford score (P value 0.458). Patellofemoral Compartment (PFC) MRI ICRS ranged from 0 to 4. There was no association between PFC ICRS score and subsequent change in oxford knee score (P value .276)

Radiographs may under report severity of some medial sided knee osteoarthritis. We conclude that in patients with grade 3 KL score that would normally not be considered for UKR, pre-operative MRI might identify grade 4 ICRS scores and this subset of patients have equivalent outcomes to patients with radiographic Grade 4 KL medial compartment osteoarthritis.

The bone-patellar tendon-bone (BTB) autograft is associated with difficulty kneeling following anterior cruciate ligament (ACL) reconstruction, however it is unclear whether it results in a more painful or symptomatic knee when compared to the hamstring tendon autograft. This study aimed to identify the rate of significant knee pain and difficulty kneeling following primary ACL reconstruction and clarify whether graft type influences the risk of these complications.

Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and November 2019 were analyzed. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was analyzed to identify patients who reported significant knee pain, defined as a KOOS Pain subscale score of ≤72 points, and kneeling difficulty, defined as a patient who reported “severe” or “extreme” difficulty when they kneel. The rate of knee pain and kneeling difficulty was compared between graft types via univariate Chi-square test and multivariate binary logistic regression with adjustment for patient demographics.

4492 primary ACL reconstructions were analyzed. At 2-year follow-up, 9.3% of patients reported significant knee pain (420/4492) and 12.0% reported difficulty with kneeling (537/4492). Patients with a BTB autograft reported a higher rate of kneeling difficulty compared to patients with a hamstring tendon autograft (21.3% versus 9.4%, adjusted odds ratio = 3.12, p<0.001). There was no difference between graft types in the rate of significant knee pain (9.9% versus 9.2%, p = 0.49) or when comparing absolute values of the KOOS Pain (mean score for BTB = 88.7 versus 89.0, p = 0.37) and KOOS Symptoms subscales (mean score for BTB = 82.5 versus 82.1, p = 0.49).

The BTB autograft is a risk factor for post-operative kneeling difficulty, but it does not result in a more painful or symptomatic knee when compared to the hamstring tendon autograft.

The bone-patellar tendon-bone (BTB) autograft has a lower rate of graft failure but a higher rate of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction. Subsequent contralateral injury may be a marker of success of the BTB graft, but it is unclear whether the type of graft influences the rate of return to sport. This study aimed to compare the rates of return to weekly sport and return to preinjury activity levels between the BTB and hamstring tendon autografts following primary ACL reconstruction.

Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014-November 2019 were analyzed. The primary outcome was return to weekly sport, defined as a Marx activity score of 8, at 2-year follow-up. The secondary outcome was return to preinjury activity level, defined as a post-operative Marx activity score that was equal or greater to the patient's preinjury Marx score. Return to sport was compared between the BTB and hamstring tendon autografts via multivariate binary logistic regression with adjustment for patient demographics.

4259 patients were analyzed, of which 50.3% were playing weekly sport (n = 2144) and 28.4% had returned to their preinjury activity level (n = 1211) at 2-year follow-up. A higher rate of return to weekly sport was observed with the BTB autograft compared to the hamstring tendon autograft (58.7% versus 47.9%, adjusted odds ratio = 1.23, p = 0.009). Furthermore, the BTB autograft had a higher rate of return to preinjury activity levels (31.5% versus 27.5%, adjusted odds ratio = 1.21, p = 0.025).

The BTB autograft is associated with a higher return to sport and may explain the higher rate of contralateral ACL injury following primary ACL reconstruction.

This study aimed to identify the success rate of debridement, antibiotics and implant retention (DAIR) for prosthetic joint infection (PJI) in a large prospective cohort of patients undergoing total knee arthroplasty (TKA). The ability for different PJI classification systems to predict DAIR success was assessed.

A prospective, multicenter study of PJIs occurring between July 2014 and December 2017 in 27 hospitals across Australia and New Zealand was performed. First time PJIs following primary TKA that were managed with DAIR were analyzed. DAIR success was defined as the patient being alive with documented absence of clinical or microbiological evidence of infection and no ongoing antibiotics for the index joint at 2-year follow-up. Multivariate analysis was performed for multiple PJI classification systems to assess their ability to predict DAIR success using their respective definitions of “early” PJI (Coventry ≤1 month, International Consensus Meeting ≤90 days or Auckland <1 year), or as hematogenous versus chronic PJI (Tsukayama).

189 PJIs were managed with DAIR, with an overall success rate of 45% (85/189). Early PJIs had a higher rate of DAIR success when analyzed according to the Coventry system (adjusted odds ratio = 3.85, p = 0.008), the ICM system (adjusted odds ratio = 3.08, p = 0.005) and the Auckland system (adjusted odds ratio = 2.60, p = 0.01). DAIR success was lower in both hematogenous (adjusted odds ratio = 0.36, p = 0.034) and chronic PJIs (adjusted odds ratio = 0.14, p = 0.003) occurring more than one year since the primary TKA.

DAIR success is highest when performed in infections occurring within one year of the primary TKA. Late infections had a high DAIR failure rate irrespective of their classification as hematogenous or chronic. Time since primary is a useful predictor of DAIR success.

The optimal timing of when to perform manipulation under anesthesia (MUA) for stiffness following total knee arthroplasty (TKA) is unclear. This study aimed to identify the risk factors for MUA following primary TKA and whether performing an “early” MUA within 3 months results in a greater improvement in range of motion.

Primary TKAs performed between January 2013 and December 2018 at three tertiary New Zealand hospitals were reviewed. International Classification of Diseases discharge coding was used to identify patients who underwent an MUA. Multivariate Cox regression was performed to identify patient and surgical risk factors for MUA. Pre- and post-MUA knee flexion angles were identified through manual review of operation notes. Multivariate linear regression was performed to compare the mean flexion angles pre- and post-MUA, as well as the mean gain in flexion, between patients undergoing “early” (<3 months) versus “late” MUA (>3 months).

7386 primary TKAs were analyzed in which 131 underwent subsequent MUA (1.8%). Patients aged <65 years were two times more likely to undergo MUA compared to patients aged ≥65 years (2.5% versus 1.3%, adjusted hazard ratio = 2.1, p<0.001). Gender, body mass index, patient comorbidities or a history of cancer were not associated with the risk of MUA. There was no difference in the final post-MUA flexion angle between patients who underwent early versus late MUA (104.7 versus 104.1 degrees, p = 0.819). However, patients who underwent early MUA had poorer pre-MUA flexion (72.3 versus 79.6 degrees, p = 0.012), and subsequently had a greater overall gain in flexion compared to patients who underwent late MUA (mean gain 33.1 versus 24.3 degrees, p<0.001).

Younger age was the only patient risk factor for MUA. A greater overall gain in flexion was achieved in patients who underwent early MUA within 3 months.

Source of the study: University of Auckland, Auckland, New Zealand and University of Otago, Christchurch, New Zealand

Outcomes following knee arthroplasty are typically defined as implant survivorship at defined timepoints, or revision incidence over time. These estimates are difficult to conceptualise, and lack context for younger patients with more remaining years of life. We therefore aimed to determine a ‘lifetime’ risk of revision as a more useful metric for total (TKA) and unicompartmental knee arthroplasty (UKA).

The New Zealand Joint Registry was used to identify 96,497 primary TKAs and 13,481 primary UKAs performed between 1999 and 2019. Patient mortality and revision incidence were also extracted. Estimates of lifetime risk were calculated using an actuarial lifetable method. The estimates were stratified by age and gender. Reasons for revision were categorised using previously published standardised definitions.

The lifetime risk of UKA revision was two-fold higher than TKA across all age groups (range 3.7-40.4% UKA, 1.6-22.4% TKA). Revision risk was higher for males with TKA (range 3.4%-25.2% males, 1.1%-20% females), but higher for females with UKA (range 4.3%-43.4% vs. 2.9%-37.4% for males). Revision due to infections were higher for TKA (1.5% males, 0.7% females) compared with UKA (0.4% males, 0.1% females). The increased risk in younger UKA patients was associated with higher incidence of aseptic loosening (UKA 2%, TKA 1%) and ‘unexplained pain’ (UKA 2%, TKA 0.2%).

The risk for UKA was two-fold higher than TKA, and this was partially explained by a higher proportion of revisions due to ‘unexplained pain’. For TKA, males had higher risk of revision, in contrast to UKA where females had higher risk; this gender difference was associated with higher incidence of infections with TKA. Younger age, gender and higher ASA status were also associated with increased lifetime risk of UKA revision. Lifetime risk of revision can provide a meaningful measure of arthroplasty outcomes to aid patient counselling.

The optimal method of tibial fixation when using a hamstring tendon autograft in anterior cruciate ligament (ACL) reconstruction is unclear. This study aimed to compare the risk of revision ACL reconstruction between suspensory and interference devices on the tibial side.

Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. Only patients with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. The rate of revision ACL reconstruction was compared between suspensory and interference devices on the tibial side. Univariate Chi-Square test and multivariate Cox regression was performed to compute hazard ratios (HR) and 95% confidence intervals (CI) with adjustment for age, gender, time-to-surgery, activity at the time of injury, number of graft strands and graft diameter.

6145 cases were analyzed, of which 59.6% were fixed with a suspensory device on the tibial side (n = 3662), 17.6% fixed with an interference screw with a sheath (n = 1079) and 22.8% fixed with an interference screw without a sheath (n = 1404). When compared to suspensory devices (revision rate = 3.4%), a higher risk of revision was observed when using an interference screw with a sheath (revision rate = 6.2%, adjusted HR = 2.05, 95% CI 1.20 – 3.52, p = 0.009) and without a sheath (revision rate = 4.6%, adjusted HR = 1.81, 95% CI 1.02 – 3.23, p = 0.044). The number of graft strands and a graft diameter of ≥8 mm did not influence the risk of revision.

When reconstructing the ACL with a hamstring tendon autograft, the use of an interference screw, with or without a sheath, on the tibial side has a higher risk of revision when compared to a suspensory device.

Arthrofibrosis is a less common complication following anterior cruciate ligament (ACL) reconstruction and there are concerns that undergoing early surgery may be associated with arthrofibrosis. The aim of this study was to identify the patient and surgical risk factors for arthrofibrosis following primary ACL reconstruction.

Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. The Accident Compensation Corporation (ACC) database was used to identify patients who underwent a subsequent reoperation with review of operation notes to identify those who had a reoperation for “arthrofibrosis” or “stiffness”. Univariate Chi-Square test and multivariate Cox regression analysis was performed. Hazard ratios (HR) with 95% confidence intervals (CI) were computed to identify the risk factors for arthrofibrosis.

9617 primary ACL reconstructions were analyzed, of which 215 patients underwent a subsequent reoperation for arthrofibrosis (2.2%). A higher risk of arthrofibrosis was observed in female patients (adjusted HR = 1.67, 95% CI 1.22 – 2.27, p = 0.001), patients with a history of previous knee surgery (adjusted HR = 1.97, 95% CI 1.11 – 3.50, p = 0.021) and when a transtibial femoral tunnel drilling technique was used (adjusted HR = 1.55, 95% CI 1.06 – 2.28, p = 0.024). Patients who underwent early ACL reconstruction within 6 weeks of their injury did not have a higher risk of arthrofibrosis when compared to patients who underwent surgery more than 6 weeks after their injury (3.5% versus 2.1%, adjusted HR = 1.56, 95% CI 0.97 – 2.50, p = 0.07). Age, graft type and concomitant meniscal injury did not influence the rate of arthrofibrosis.

Female sex, a history of previous knee surgery and a transtibial femoral tunnel drilling technique are risk factors for arthrofibrosis following primary ACL reconstruction.

Source of the study: University of Auckland, Auckland, New Zealand

Unicompartmental knee arthroplasty (UKA) has benefits for patients with appropriate indications. However, UKA has a higher risk of revision, particularly for low-usage surgeons. The introduction of robotic-arm assisted systems may allow for improved outcomes but is also associated with a learning curve. We aimed to characterise the learning curve of a robotic-arm assisted system (MAKO) for UKA in terms of operative time, limb alignment, component sizing, and patient outcomes.

Operative times, pre- and post-surgical limb alignments, and component sizing were prospectively recorded for consecutive cases of primary medial UKA between 2017 and 2021 (n=152, 5 surgeons). Patient outcomes were captured with the Oxford Knee Score (OKS), EuroQol-5D (EQ-5D), Forgotten Joint Score (FJS-12) and re-operation events up to two years post-UKA. A Cumulative Summation (CUSUM) method was used to estimate learning curves and to distinguish between learning and proficiency phases.

Introduction of the system had a learning curve of 11 cases. There was increased operative time of 13 minutes between learning and proficiency phases (learning 98 mins vs. proficiency 85 mins; p<0.001), associated with navigation registration and bone preparation/cutting. A learning curve was also found with polyethylene insert sizing (p=0.03). No difference in patient outcomes between the two phases were detected for patient-reported outcome measures, implant survival (both phases 98%; NS) or re-operation (learning 100% vs. proficiency: 96%; NS). Implant survival and re-operation rates did not differ between low and high usage surgeons (cut-off of 12 UKAs per year).

Introduction of the robotic-arm assisted system for UKA led to increased operative times for navigation registration and bone preparation, but no differences were detected in terms of component placement or patient outcomes regardless of usage. The short learning curve regardless of UKA usage indicated that robotic-arm assisted UKA may be particularly useful for low-usage surgeons.

The optimum indications for debridement, antibiotics and implant retention (DAIR) are unclear. Previous studies have demonstrated higher success rate of DAIR within one year of the primary arthroplasty. This study aimed to compare the success rate of DAIR vs revision in “early” and “late” infections to provide guidance for clinical decision making.

The Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort prospectively recorded PJIs between July 2014 and December 2017 in 27 hospitals. This study included PIANO patients with first time PJIs occurring after primary TKA. Treatment success was defined as the patient being alive, free from further revision and without clinical or microbiological evidence of reinfection at two years follow-up.

“Early” and “late” infections were analyzed separately. Univariate analysis compared demographic and disease specific factors between the DAIR and Revision groups. Multivariate binary logistic regression identified whether treatment strategy and other risk factors were associated with treatment success in “early” and “late” infections.

In 117 “early” (<1 year) infections, treatment success rate was 56% in the DAIR group and 54% in the revision group (p=0.878). No independent risk factors were associated with treatment outcome on multivariate analysis.

In 134 “late” (>1 year) infections, treatment success rate was 34.4% in the DAIR group and 60.5% in the revision group (OR 3.07 p=0.006). On multivariate analysis, revision was associated with 2.47x higher odds of success (p=0.041) when compared to DAIR, patients with at least one significant co-morbidity (OR 2.27, p=0.045) or with Staphylococcus aureus PJIs (OR 2.5, p=0.042) had higher odds of failure.

In “late” PJIs occurring >1 year following primary TKA, treatment strategy with revision rather than DAIR was associated with greater success. Patients with significant comorbidities and Staphylococcus aureus PJIs were at higher risk of failure regardless of treatment strategy.

Source of the study: University of Auckland, Auckland, New Zealand and University of Otago, Christchurch, New Zealand

Patient reported outcome measures (PROMs) are predictors of knee arthroplasty revision. Unicompartmental knee arthroplasty (UKA) is effective for patients with the correct indications, however has higher revision rates than total knee arthroplasty (TKA). Different revision thresholds for the procedures have been postulated. Our aims were to investigate: 1) if PROMs could predict knee arthroplasty revision within two years of the score at six months, five years and ten years follow-up, and 2) if revision ‘thresholds’ differed between TKA and UKA.

All TKAs and UKAs captured by the New Zealand Joint Registry between 1999 and 2019 with at least one OKS response at six months (TKA n=27,708, UKA n=8,415), five years (TKA n=11,519, UKA n=3,365) or ten years (TKA n=6,311, UKA n=1,744) were included. were propensity-score matched 2:1 with UKAs for comparison of revision thresholds.

Logistic regression indicated that for every one-unit decrease in OKS, the odds of TKA and UKA revision decreased by 10% and 11% at six months, 10% and 12% at five years and 9% and 5% at ten years. Fewer TKA patients with ‘poor’ outcomes (≤25) subsequently underwent revision compared with UKA at six months (5.1% vs. 19.6%, p<0.001), five years (4.3% vs. 12.5%, p<0.001) and ten years (6.4%vs. 15.0%, p=0.02). Compared with TKA, UKA patients were 2.5 times more likely to undergo revision for ‘unknown’ reasons, bearing dislocations and disease progression.

The OKS is a strong predictor of subsequent knee arthroplasty revision within two years of the score from early to late term. A lower revision threshold was found with UKA when compared with a matched TKA cohort. Higher revision rates of UKA are associated with both lower clinical thresholds for revision and additional modes of UKA failure.

Meniscal repairs are commonly performed during anterior cruciate ligament (ACL) reconstruction. This study aimed to identify the risk factors for meniscal repair failure following concurrent primary ACL reconstruction.

Primary ACL reconstructions with a concurrent repair of a meniscal tear recorded in the New Zealand ACL Registry between April 2014 and December 2018 were analyzed. Meniscal repair failure was defined as a patient who underwent subsequent meniscectomy, and was identified after cross-referencing data from the ACL Registry with the national database of the Accident Compensation Corporation (ACC). Multivariate Cox regression was performed to produce hazard ratios (HR) with 95% confidence intervals (CI) to identify the patient and surgical risk factors for meniscal repair failure.

2041 meniscal repairs were analyzed (medial = 1235 and lateral = 806). The overall failure rate was 9.4% (n = 192). Failure occurred in 11.1% of medial (137/1235) and 6.8% of lateral (55/806) meniscal repairs. The risk of medial failure was higher with hamstring tendon autografts (adjusted HR = 2.00, 95% CI 1.23 – 3.26, p = 0.006) and in patients with cartilage injury in the medial compartment (adjusted HR = 1.56, 95% CI 1.09 – 2.23, p = 0.015). The risk of lateral failure was higher when the procedure was performed by a surgeon with an annual case volume of less than 30 ACL reconstructions (adjusted HR = 1.92, 95% CI 1.10 – 3.33, p = 0.021). Age, gender, time from injury-to-surgery and femoral tunnel drilling technique did not influence the risk of meniscal repair failure.

When repairing a meniscal tear during ACL reconstruction, the use of a hamstring tendon autograft or the presence of cartilage injury in the medial compartment increases the risk of medial meniscal repair failure. Lower surgeon case volume increases the risk of lateral meniscal repair failure.

Source of the study: University of Auckland, Auckland, New Zealand

Unicompartmental knee arthroplasty (UKA) is effective for patients with isolated compartment osteoarthritis, however the procedure has higher revision rates. Long-term survivorship and accurate characterisation of revision reasons are limited by a lack of long-term data and standardised revision definitions. We aimed to identify survivorship, risk factors and revision reasons in a large UKA cohort with up to 20 years follow-up.

Patient, implant and revision details were recorded through clinical and radiological review for 2,137 consecutive patients undergoing primary medial UKA across Auckland, Canterbury, Counties Manukau and Waitematā DHB between 2000 and 2017. Revision reasons were determined from review of clinical, laboratory, and radiological records for each patient using a standardised protocol. To ensure complete follow-up data was cross-referenced with the New Zealand Joint Registry to identify patients undergoing subsequent revision outside the hospitals. Implant survival, revision risk and revision reasons were analysed using Cox proportional-hazards and competing risk analyses.

Implant survivorship at 15 years was comparable for cemented fixed-bearing (cemFB; 91%) and uncemented mobile-bearing (uncemMB; 91%), but lower for cemented mobile-bearing (cemMB; 80%) implants. There was higher incidence of aseptic loosening with cemented implants (3-4% vs. 0.4% uncemented, p<0.01), osteoarthritis (OA) progression with cemMB implants (9% vs. 3% cemFB/uncemMB; p<0.05) and bearing dislocations with uncemMB implants (3% vs. 2% cemMB, p=0.02). Compared with the oldest patients (≥75 years), there was a nearly two-fold increase in risk for those aged 55-64 (hazard ratio 1.9; confidence interval 1.1–3.3, p=0.03). No association was found with gender, BMI or ASA.

Cemented mobile-bearing implants and younger age were linked to lower implant survivorship. These were associated with disease progression and bearing dislocations. The use of cemented fixed-bearing and uncemented mobile-bearing designs have superior comparable long-term survivorship.

The New Zealand Joint Registry (NZJR) was established in 1999. However, ethnicity data was not recorded by prioritisation in line with Ministry of Health (MoH) recommendations. Recently, cross-referencing with MoH updated ethnicity data for all 326,150 entries in the NZJR database. The objective of this national level, population study was to identify any ethnic disparities in access and outcome for Māori for primary total hip (THA) and knee arthroplasty (TKA) for Osteoarthritis.

The utilisation rate for THA and TKAs were calculated for the Māori and NZ European population from all data in the NZJR and Census data in 2001, 2006, 2013 and 2018. Utilisation rate was reported separately for four age groups (<55, 55-64, 65-74, >75) over four time periods (1999-2004, 2005-2009, 2010-2014, 2015-2020). Revision rate, 6 months and 5-year Oxford scores were adjusted for age, sex and BMI, then compared between groups.

In every age group and at all but one time point, significant under-utilisation of TKA was observed in Māori. For THAs, Māori had similar utilisation rates in the <55 and 55-64 age groups, but significantly lower utilisation rates in all other age groups.

When adjusted for age, sex and BMI, no significant differences in revision rates were observed between Māori and NZ Europeans for THAs (HR 0.939, P 0.417) or TKAs (HR 1.129, P 0.149). Adjusted 6 months and 5-year Oxford scores were significantly higher in NZ Europeans, however, the maximum difference was less than 3 points and is unlikely to be clinically significant.

Despite the same risk of being diagnosed with osteoarthritis, Māori are less likely to undergo THA and TKA. There are no clinically significant differences in outcomes post arthroplasty between Māori and NZ Europeans. Further research is required to investigate causes for lower utilisation in Māori.

Little information exists regarding optimal tibial stem usage in revision total knee arthroplasty (rTKA) utilising a tibial trabecular metal (TM) cone. The purpose of this study was to compare 1) functional outcomes, 2) radiographic outcomes, and 3) implant survivorship in rTKA utilising TM cones combined with either short stems (SS) or long stems (LS) at minimum two-years clinical follow-up.

In this retrospective, multi-centre study, patients undergoing TM cone utilising rTKA between 2008 and 2019 were included. Patients were divided into: SS group (no diaphyseal engagement), and LS group (diaphyseal engagement). All relevant clinical charts and post-operative radiographs were examined. Oxford Knee Score (OKS) and EuroQol-5D (EQ-5D-5L) data were collected at most recent follow-up.

In total, 44 patients were included: 18 in the SS group and 26 in the LS group. The mean time of follow-up was 4.0 years. Failure free survival was 94.5% for the SS group and 92.3% for the LS group. All failures were for prosthetic joint infections managed with debridement, antibiotics, and implant retention. At most recent follow-up, 3 patients demonstrated radiographic signs of lucency (1 SS 2 LS, p = 1) and the mean OKS were 37 ± 4 and 36 ± 6 (p = 0.73) in the SS and LS groups, respectively.

Tibial SS combined with TM cones performed as well as LS in rTKA at minimum two-years follow-up. A tibial SS in combination with a TM cone is a reliable technique to achieve stable and durable fixation in rTKA.

Aims

Day-case arthroplasty is gaining popularity in Europe. We report outcomes from the first 12 months following implementation of a day-case pathway for unicompartmental knee arthroplasty (UKA) and total hip arthroplasty (THA) in an NHS hospital.

No animal model currently exists for hip abductor tendon tears. We aimed to 1. Develop a large animal model of delayed abductor tendon repair and 2. To compare the results of acute and delayed tendon repair using this model.

Fourteen adult Romney ewes underwent detachment of gluteus medius tendon using diathermy. The detached tendons were protected using silicone tubing. Relook was performed at six and 16 weeks following detachment, histological analysis of the muscle and tendon were performed. We then attempted repair of the tendon in six animals in the six weeks group and compared the results to four acute repairs (tendon detachment and repair performed at the same time). At 12 weeks, all animals were culled and the tendon–bone block taken for histological and mechanical analysis.

Histology grading using the modified Movin score confirmed similar tendon degenerative changes at both six and 16 weeks following detachment. Biomechanical testing demonstrated inferior mechanical properties in both the 6 and 16 weeks groups compared to healthy controls.

At 12 weeks post repair, the acute repair group had a lower Movin's score (6.9 vs 9.4, p=0.064), and better muscle coverage (79.4% of normal vs 59.8%). On mechanical testing, the acute group had a significantly improved Young's Modulus compared to the delayed repair model (57.5MPa vs 39.4MPa, p=0.032)

A six week delay between detachment and repair is sufficient to produce significant degenerative changes in the gluteus medius tendon. There are significant histological and mechanical differences in the acute and delayed repair groups at 12 weeks post op, suggesting that a delayed repair model should be used to study the clinical problem.

Introduction

Primary fixation in uncemented Total Hip Replacement (THR) is achieved by implanting an appropriately sized stem. Last year, in our pilot study, we classified undersizing & reported the incidence of subsidence & radiolucent lines (RLL) in undersized uncemented stems. Now we report on a larger cohort of patients, reporting undersizing and its association with radiolucent lines and subsidence. Secondarily we report on the effect of using a collar, patients' BMI, and in a smaller group the five-year failure rate.

Introduction

Undersizing of an uncemented femoral stem is a post-operative description of a radiograph with unclear clinical importance. It may not always translate into a suboptimal clinical outcome.

Recent studies have demonstrated that implant-specific blood metal ion thresholds exist in unilateral and bilateral metal-on-metal (MoM) hip arthroplasty patients, with these thresholds being most effective for identifying patients at low-risk of adverse reactions to metal debris (ARMD). We investigated whether these new blood metal ion thresholds could effectively identify patients at risk of ARMD in an external cohort of MoM hip arthroplasty patients.

We performed a validation study involving 803 MoM hip arthroplasties implanted in 710 patients at three European centres (323=unilateral Birmingham Hip Resurfacing (BHR); 93=bilateral BHR; 294=unilateral Corail-Pinnacle). All patients underwent whole blood metal ion sampling. Patients were divided into those with ARMD (revised for ARMD or ARMD on imaging; n=75), and those without ARMD (n=635). Previously devised implant-specific blood metal ion thresholds (cobalt=2.15μg/l for unilateral BHR; maximum cobalt or chromium=5.5μg/l for bilateral BHR; cobalt=3.57μg/l for unilateral Corail-Pinnacle) were applied to the validation cohort, with receiver operating characteristic curve analysis used to establish the discriminatory characteristics for each respective threshold.

The area under the curve, sensitivity, specificity, positive predictive value and negative predictive value for distinguishing between patients with and without ARMD for each implant-specific threshold were respectively: unilateral BHR=89.4% (95% CI=82.8%-96.0%), 78.9%, 86.7%, 44.1%, 96.9%; bilateral BHR=89.2% (95% CI=81.3%-97.1%), 70.6%, 86.8%, 54.5%, 93.0%; unilateral Corail-Pinnacle=76.9% (95% CI=63.9%-90.0%), 65.0%, 85.4%, 24.5%, 97.1%. The 7μg/l UK MHRA threshold missed significantly more patients with ARMD compared with the implant-specific thresholds (4.9% vs. 2.8%; p=0.0003).

This external multi-centre validation study has confirmed that MoM hip arthroplasty patients with blood metal ion levels below newly devised implant-specific thresholds have a low-risk of ARMD. Compared to implant-specific thresholds, the currently proposed fixed MHRA threshold missed more patients with ARMD.

We recommend using implant-specific thresholds over fixed thresholds when managing MoM hip arthroplasty patients.

When inserting a femoral stem, surgeons make use of many visual and tactile cues to be sure that the implant is correctly sized and well-seated. One such cue is the change of pitch that can be heard when the final femoral broach is inserted. This is known to be important, but has not been widely studied.

We set out to analyse the sounds produced during femoral broaching and implant fixation, and to discover whether the absence of these sounds could predict a poor fixation.

We recorded the sound of femoral broaching and definitive implant insertion, for twenty un-cemented Corail total hip replacements. Procedures were performed by the same surgeon, in the same theatre. The recordings were visualised using audio editing software, and a Fast Fourier Transform was used to identify the dominant audio frequencies.

In 19 of the 20 cases, the final strikes of the final femoral broach displayed a distinctive pattern, with the most prominent frequencies being harmonics (multiples of a fundamental frequency) which had a wavelength directly related to the length of the femoral canal. This contrasts with initial strikes, where multiple unrelated frequencies were present.

Postoperative radiographs were examined by two surgeons independently, to assess implant sizing and positioning. The one case, in which the harmonic pattern was not observed, was found on radiographs to be an undersized, varus malpositioned implant.

We demonstrate that a characteristic frequency pattern is present when impacting cancellous bone with a well-sized and well-placed femoral broach. When the pattern was absent, the broach and implant were undersized and malpositioned. We hypothesise that this pattern arises when broach and femur are vibrating as one, indicating adequate contact with, and compression of, cancellous bone.

Introduction

The original Charnley-type negative pressure body exhaust suit reduced infection rates in randomized trials of total joint arthroplasty decades ago. Modern positive pressure surgical helmet systems (SHS) have not shown similar benefit, and several recent studies have shown a trend towards increased wound contamination and infection with SHS use. The gown glove interface may be one source of particle contamination.

Introduction

Local commissioning groups are no longer funding outpatient follow up of joint replacements in an effort to save money. We present the costs of changing from traditional follow up methods to a virtual clinic at Warwick Hospital. Before September 2014 all joint replacements were seen in outpatients at six weeks, one year, five years, ten years and then every two years thereafter. They were usually reviewed, in a non-consultant led clinic, by a Band 7 specialist physiotherapist. This cost approximately £50 per patient including x-ray. Occasionally, the patients were seen in a consultant led clinic costing approximately £100.

Introduction

During broach preparation and implant insertion of the proximal femur the surgeon may be able to use audible pitch changes to judge broaching adequacy and implant position. The aim of this study was to analyse the sound produced and explain the sound spectra using acoustic physics.

Acute achilles tendon ruptures are increasing in incidence and occur in 18 per 100 000 people per year, however there remains a lack of consensus on the best treatment of acute ruptures. Randomised studies comparing operative versus non-operative treatment show operative treatment to have a significantly lower re-rupture rate, but these studies have generally used non-weight bearing casts in the non-operative group.

Recent series utilizing more aggressive non-operative protocols with early weight-bearing have noted a far lower incidence of re-rupture, with rates approaching those of operative management. Weight bearing casts may also have the advantages of convenience and an earlier return to work, and the purpose of this study was to compare outcomes of traditional casts versus Bohler-iron equipped weight-bearing casts in the treatment of acute Achilles tendon ruptures.

83 patients with acute Achilles tendon ruptures were recruited from three Auckland centres over a 2 year period. Patients were randomised within one week of injury to receive either a weight-bearing cast with a Bohler iron or a traditional non weight-bearing cast. A set treatment protocol was used, with a total cast time of eight weeks. Patients underwent detailed muscle dynamometry testing at 6 months, with further follow up at 1 year and at study completion. Primary outcomes assessed were patient satisfaction, time to return to work, and overall re-rupture rates. Secondary outcomes included return to sports, ankle pain and stiffness, footwear restrictions, and patient satisfaction.

There were no significant differences in patient demographics or activity levels prior to treatment. At follow up, 1 patient (2%) in the Bohler iron group and 2 patients (5%) in the non weight bearing group sustained re-ruptures (p=0.62). There was a trend toward an earlier return to work in the weight-bearing group, with 58% versus 43% returning to work within 4 weeks, but the difference was not significant. 63% of patients in the weight bearing group reported freedom from pain at 12 months compared to 51 % in the non weight bearing group. There were no statistically significant differences in Leppilahti scores, patient satisfaction, or return to sports between groups.

Weight-bearing casts in the non-operative treatment of Achilles tendon ruptures appear to offer outcomes that are at least equivalent to outcomes of non-weight bearing casts. The overall rerupture rate in this study is low, supporting the continued use of initial non-operative management in the treatment of acute ruptures.

NICE technology appraisal guidance 157 suggests that the oral anticoagulation medication Dabigatran etexilate (Pradaxa®, Boehringer Ingelheim) can be used for the primary prevention of venous thromboembolic events (VTE's) in adult patients who have undergone elective total hip (THR) or knee replacement (TKR) surgery.

The NICE guidance and the Pradaxa® Summary of Product characteristics (SPC) report that 13.8% of patients receiving recommended doses of Dabigatran experience adverse bleeding events. In the manufacturer's pivotal clinical trials, wound secretion accounted for 4.9% of patients treated with Dabigatran as compared to 3.0% treated with Enoxaparin.

The aim of this audit was to assess the impact of Dabigatran on wound complications at a UK district general hospital and to quantify the effect on the postoperative discharge home support services provided by the award-winning South Warwickshire Accelerated Transfer Team (SWATT).

We report our experience of Dabigatran use at Warwick Hospital from March 2009 to March 2010.

Of the 788 lower limb arthroplasties performed, 681 patients (81.0%) were accepted for SWATT follow-up. Fifty-five (8.6%) of patients accepted by SWATT showed increased wound secretion for greater than 5 days. This included 12.7% of THR and 5.5% of TKR patients. Increased wound secretion resulted in 226 extra home visits by SWATT, at an extra cost of £23,104 (7.5% increase in SWATT budget).

Twenty-six of the 55 patients had positive microbial growth when wound secretions were swabbed. Five patients were admitted for management of wound infections. Incidentally, there were 2 reported cases of DVT and PE. These were not in the increased wound secretion patients.

In summary, Dabigatran at Warwick Hospital was associated with a higher than predicted incidence of surgical site morbidity, increased resource output and increased postoperative discharge costs. As a consequence, Dabigatran use has been reduced and other oral anticoagulants are being trialled.

Despite modern surgical techniques, reported rates of deep infection following Total Knee Replacement (TKR) persist between 1–2.5%. Coagulase-negative staphylococcus (CNS) has become the most common causative organism, and while growth of CNS is more indolent thanstaphylococcus aureus, it has a relatively higher minimum inhibitory concentration (MIC) against cephalosporins. Tissue concentrations of prophylactic antibiotics may fall below this level during TKR with conventional ‘systemic’ dosing.

Regional administration of prophylactic antibiotics via a foot vein following tourniquet inflation has been shown to provide tissue concentrations approximately 10 times higher than systemic dosing, however cannulation of a foot vein is difficult, time consuming, and may compromise sterility.

Intraosseous cannulation offers an alternative method of accessing the vascular system, and the aim of this study was to assess its effectiveness in administration of prophylactic antibiotics. 22 patients undergoing primary total knee arthroplasty were randomised into two groups. Group 1 received 1g of cephazolin systemically 10 minutes prior to tourniquet inflation. In Group 2 the EZ-IO tibial cannulation system was used, and 1g of cephazolin was administered intraosseously in 200ml of normal saline following tourniquet inflation and prior to skin incision. Subcutaneous fat and femoral bone samples were taken at set intervals during the procedure, and antibiotic concentrations measured using High Performance Liquid Chromatography (HPLC).

There were no significant differences in patient demographics, comorbidities, or physical parameters between groups. The overall mean tissue concentration of cephazolin in subcutaneous fat was 185.9μg/g in the intraosseous group and 10.6μg/g in the systemic group (p<0.01). The mean tissue concentration in bone was 129.9 μg/g in the intraosseous group and 11.4μg/g in the systemic group (p<0.01). These differences were consistent across all sample time points throughout the procedure. No complications occurred in either group.

Intraosseous regional administration can achieve tissue levels of antibiotic over an order of magnitude higher than systemic administration. Further work is required to determine if there is clinical benefit in preventing infection, particularly against CNS. This novel mode of drug administration may also have other applications, allowing ‘surgical site delivery’ of medication while minimising systemic side effects.

NICE technology appraisal guidance 157 suggests that the oral anticoagulation medication Dabigatran etexilate can be used for the primary prevention of venous thromboembolic events (VTE's) in adult patients who have undergone elective total hip or knee replacement surgery.

The NICE guidance reports that 13.8% of patients receiving recommended doses of Dabigatran experienced adverse bleeding events. In the pivotal hip and knee VTE trial, wound secretion only accounted for 4.9% of patients treated with Dabigatran (cf 3.0% of patients treated with Enoxaparin).

We report our wound secretion experience after Dabigatran use at Warwick Hospital from March 2009 to March 2010. Of the 788 lower-limb arthroplasties performed, 55 patients (6.9%) had oozing wounds after discharge (Mean=8 days, Range=1-39 days). This resulted in 226 extra home-visits by discharge nurses, 26 positive microbiology cultures and 5 confirmed wound infections needing antibiotic treatment and/or surgical intervention. Incidentally, there were also 2 known cases each of deep vein thrombosis and pulmonary embolus in this cohort. The number of complications was markedly increased from previous years when LMWH was the VTE prophylaxis used.

This data suggests that the use of Dabigatran in Warwick Hospital may significantly increase surgical site morbidity and resource output after lower limb arthroplasty.

The “Wallis” implant is indicated to stabilize symptomatic degenerative lumbar spine segments, relieving low back pain related to instability and thus delaying the need for irreversible, more invasive surgical management. The purpose of this study was to provide the first objective clinical evaluation of the “Wallis” lumbar dynamic stabilisation system.

An independent prospective observational study was carried out utlising SF-36, Oswestry Disability Index (ODI) and visual analogue pain scores (VAS). Surgical pathologies in which this technique was used, the intra-operative and post-operative complications and length of post-op stay were recorded. 102 patients underwent Wallis insertion between June 2007- May 2009, Median age 51.5 (range 28-108). 94% of patients completed questionnaires and were followed up at 3, 6 and 12 month time points. ODI scores decreased from pre-op 39 to 27 at twelve months (p<.0016). VAS back pain scores decreased 59 to 36 (p<0.0001). Leg scores decreased 50 to 39 (p<0.0002). SF 36 scores improved significantly, physical functioning 46 to 59, physical health 30 to 54 and social functioning 47 to 68. 50% of patients believed their health to be better 12 months post-op. Pre-operatively 28% of patients were employed and working with 26% off work due to back problems. This rate increased steadily with 42% employed at 12 months. Two implants were removed, one due to non-benefit with subsequent arthrodesis and one due to infection. One superficial wound infection occurred.

The Wallis dynamic stabilization system provides a superficial and easily reversible surgical procedure with a lower complication rate than conventional athrodesis. Used in patients with painful degenerative lumbar conditions their quality of life objectively approached values of the age- and gender-matched general population.

Cuff tear arthropathy represents a challenge to the shoulder arthoplasty surgeon. The poor results of conventional total shoulder arthroplasty in cuff deficient shoulders secondary to glenoid component loosening have meant hemiarthroplasty has traditionally been the preferred surgical option. Recently reverse total shoulder arthroplasty (RSA) has gained increasing popularity due to a clinical perception of an improved functional outcome, despite the absence of comparative data. The aim of this study was to compare the early functional results of Hemiarthroplasty versus RSA in the management of cuff-tear arthropathy.

102 primary hemiarthroplasties performed for cuff tear arthropathy were compared against 102 RSAs performed for the same diagnosis. Patients were identified from the New Zealand National Joint Registry and matched for age, sex, and American Society of Anesthesiologists (ASA) scores. Oxford shoulder scores (OSS) were collected at 6 months and 5 years post operatively and were compared between the two groups, together with mortality and re-revision rates.

There were 51 males and 51 females in each group, with a mean age of 71.6 in the Hemiarthroplasty group and 72.6 in the RSA group. The mean ASA score was 2.2 in both groups. The mean OSS was 31.1 in the hemiar-throplasty group and 38.1 in the RSA group. At follow up, there were 7 revisions in the hemiarthroplasty group and 5 in the RSA group. No difference in mortality was seen between the two groups.

This study provides the first direct evidence of a improved functional outcome of RSA compared to Hemiarthroplasty in the treatment of patients with cuff tear arthropathy. Longer term follow up is needed to confirm that the improved function is maintained, and that late complications such as component loosening remain comparable between the two groups.

Developmental Hip Dysplasia (DDH) presents considerable technical challenges to the primary arthroplasty surgeon. Autogenous bulk grafting using the femoral head has been utilised to achieve anatomic cup placement and superolateral bone coverage in these patients, but reported outcomes on this technique have been mixed with lack of graft integration and subsequent collapse seen as an early cause of failures. Achieving union and incorporation of the autogenous graft have been identified as key determinants of a successful outcome with this technique. The main factors affecting incorporation are stability of the construct and host-graft bone contact. We describe a novel technique combining the use of bulk autograft with an iliac osteotomy, which provides primary stability and optimises direct cancellous-cancellous bone contact.

21 hips in 21 patients with DDH underwent this technique and were followed for a mean 8.1 years. The pre-operative radiographic classification was Crowe type I in 12 hips (57%), type II in 4 hips, and type III in 5 hips, and the mean Sharp angle was 49.6° (range 42–60°). All grafts united by year. At time of follow up, there was no radiographic evidence of graft collapse or loosening. There were no reoperations.

Our study has shown that this technique variation combining an iliac osteotomy with bulk autograft in cases of developmental hip dysplasia provides early stability and reliable graft incorporation, together with satisfactory clinical and radiological outcomes in the medium term. Longer term study is necessary to confirm the clinical success of this procedure.

Introduction: Disagreement exists in the literature as to whether hip resurfacing requires more acetabular reaming than uncemented hip replacement.

Materials and Methods: Thirty-nine patients underwent total hip arthroplasty with a large metal on metal resurfacing acetabular cup and large metal head with a conventional uncemented femoral stem. Although there was no change in routine operative technique the femoral neck was measured (as if for resurfacing) before being cut. The size of the acetabular component actually inserted was compared with the smallest size which could have been used had a resurfacing been carried out for each patient. A two tailed paired t test was carried out.

Results: We found that there was no difference in female patients but in men the actual cup used was 2.44mm smaller than the smallest possible resurfacing cup which equates to 6.39cm³ less bone (p < 0.0001).

Discussion: By using paired samples we have reduced confounding factors and shown that a large metal on metal bearing on a conventional stem is more conservative of acetabular bone than hip resurfacing in male patients.

Mechanical prophylaxis with foot-pumps provides an interesting alternative to chemical agents in the prevention of thomboembolic disease following major orthopaedic surgery procedures. Recent studies have suggested that simultaneous use of graduated compression stockings (GCS) may hinder the pneumatic compression effect of foot pumps. The hypothesis of this prospective study was that the use of foot-pumps without GCS does not affect the efficacy of DVT prophylaxis, and improves patient compliance. 846 consecutive patients admitted at a single institution undergoing total hip (THR) or knee replacement (TKR) were included in the study. The A-V Impulse System^® foot-pump units (Orthofix Vascular Novamedix, Andover, UK) was used in all patients. Forty-six patients discontinued the use of foot-pumps, leaving 400 patients who received foot-pumps in combination with GCS and 400 patients with foot pumps alone. Eleven patients of the stocking group (2.7%) and 9 patients of the no-stockings group (2.3%) developed postoperative symptomatic DVT (p=0.07). DVT was more frequent in TKR (10 of 364; 2.7%) than in THR (10 of 436; 2.3%). Non-fatal pulmonary embolism occurred in 4 patients out of 20 with symptomatic DVT, 2 each of the stockings and no stockings groups. The foot pump discontinuation rate of patients treated with stockings was 7%, versus 4% of patients treated without stockings (p< 0.05). In conclusion, management of patients with foot-pumps without GCS does not reduce efficacy of DVT prophylaxis after THR and TKR, and improves patient compliance.

Background: There has been much interest recently in reducing the length of inpatient stay after hip and knee arthroplasty and much of the relevant literature has linked this to minimally invasive surgery. Orthopaedic departments are often under great pressure to reduce inpatient stay in order to increase throughput of patients. However it is incumbent on those of us responsible for patient care to ensure that systems are in place to maintain safety.

Patients and Methods:We looked at a 6 month period of early discharge with a dedicated ‘Accelerated Discharge Team’ (A.T.T.) at our institution. The team consisted of three nurses, two physiotherapists and two ‘technical instructors’. All patients undergoing hip or knee arthroplasty were assessed pre-operatively and post-operatively for admission to the care of the A.T.T. against fixed criteria. Patients were visited at home on the day of discharge and every day until released from the care of the team. 333 patients underwent lower limb arthroplasty during the study period of which 305 (91.6%) were admitted to the care of the A.T.T.

Results: The mean lengths of stay for primary hip and knee replacements were 3.43 and 3.30 days respectively. The mean for revision hip and knee were 5.75 and 3.29 days respectively. 66% (95% C.I. 57%–74%) of patients undergoing primary hip arthroplasty went home by 3 days and 91% (95% C.I. 85%–95%) by 4 days. 73% (95% C.I. 64%–81%) of patients undergoing total knee arthroplasty went home by 3 days and 93% (95% C.I. 87%–97%) by 4 days. The most common reasons for delay were: social reasons or living alone; low blood pressure or haemoglobin level; difficulty walking. Of the 305 patients, 12 (4%) were readmitted to hospital within 6 weeks of discharge, 2 of these patients (1%) were still under the care of the A.T.T. Almost 90% of patients responded to a satisfaction survey. 94.2% of those responding indicated that they would use the A.T.T. scheme again.

Discussion: Other authors have linked early discharge to minimally invasive surgery or to special anaesthetic/ analgesic techniques. It has also been shown that both carepathways and patient education protocols can reduce length of stay. In the year before implementing the A.T.T. the mean stay for primary hip and knee replacements was over 9 days. We were able to reduce this to less than 3.5 days for over 90% of our patients during the study period. This was achieved safely and without any special surgical or anaesthetic techniques. The total cost of the scheme was just under £100 000 for the 6 month period. We estimate that 2000 bed days were saved during the same period. This is cost effective on these terms alone. As well as transferring 12 elective orthopaedic beds to a different department we were able to perform an estimated 75 extra lower limb arthroplasties in the 6 month period.

Treatment of complex proximal humeral fractures remains controversial. In situations where accurate fracture reduction and fixation cannot be obtained, arthroplasty may be the preferred surgical option. The traditional operation of hemiarthroplasty in these situations is technically challenging, and a good functional outcome is dependent on reduction and healing of the tuberosities. Reverse Shoulder Arthroplasty (RSA) has been suggested as an alternative, and we sought to analyse and compare functional outcomes following the two procedures.

Ten patients who underwent hemiarthroplasty for acute fracture of the proximal humerus between 1999 and 2003 were reviewed. All fractures were assessed intraoperatively for open reduction and internal fixation of the fracture, but deemed to be unsuitable for fixation. From 2003 our management in this clinical situation changed, and ten subsequent patients underwent reverse shoulder arthroplasty using the S.M.R. reverse shoulder prosthesis (Systema Multiplana Randell, Lima, Italy). Clinical and radiological follow up was carried out at a mean of 31 months (hemiarthroplasty patients) and 15 months (RSA patients) post operatively.

Subjectively seven of 10 patients in the reverse group and seven of 10 patients in the hemiarthroplasty group rated their outcome as ‘very good’ or ‘excellent’. The mean ASES scores were 65 (range 40–88) in the reverse group and 67 (26–100) in the hemiarthroplasty group. The mean Oxford shoulder score was 29 (15–56) in the reverse group and 22 (12–34) in the hemiarthroplasty group. The mean active forward elevation in the hemiarthroplasty group was 108° (range 50–180) and in the reverse group 115° (45–40), and active external rotation 49° (5–105) and 48° (10–90) respectively. Differences in outcome scores between the two groups were not statistic ally significant (p value> 0.05).

This study provides the first direct comparison between RSA and hemiarthroplasty for complex proximal humeral fractures. The expected functional gains with Reverse shoulder arthroplasty were not seen, suggesting its use as the primary treatment for acute fracture should remain guarded.

Aim To review 6 months of early discharge with a dedicated ‘Accelerated Discharge Team’ (A.T.T.) at our institution.

Patients and Methods The team consisted of four nurses and three physiotherapists. Patients undergoing hip or knee arthroplasty were assessed pre-operatively and post-operatively for admission to the care of the A.T.T. against fixed criteria. Patients were visited at home on the day of discharge and every day until released from the care of the team. 333 patients underwent lower limb arthroplasty during the study period of which 305 (91.6%) were admitted to the A.T.T.

Results The mean length of stay for primary knee replacements was 3.30 days. 73% (95% C.I. 64%–81%) of patients undergoing total knee arthroplasty went home by 3 days and 93% (95% C.I. 87%–97%) by 4 days. Results for hip arthroplasty were similar. Of the 305 patients, 12 (4%) were readmitted to hospital within 6 weeks of discharge. Almost 90% of patients responded to a satisfaction survey. 94.2 % of those responding indicated that they would use the A.T.T. scheme again.

Discussion In the year before implementing the A.T.T. the mean stay for primary hip and knee replacements was over 9 days. We reduced this to less than 3.5 days for over 90% of our patients during the study period. The total cost of the scheme was just under £100 000 for the 6 month period. We estimate that 2000 bed days were saved during the same period. This is cost effective on these terms alone. As well as transferring 12 elective orthopaedic beds to a different department we were able to perform an estimated 75 extra lower limb arthroplasty operations in the 6 month period.

The management of peri-prosthetic fracture following total hip arthroplasty is difficult, requiring expertise in both trauma and revision surgery. With rising numbers of patients in the population living with hip prostheses in situ, their frequency is increasing, and controversy remains over their ideal management. The objective of this study was to review all peri-prosthetic fractures at a single institution to identify injury and treatment patterns, and their associated clinical outcomes.

Fifty-four peri-prosthetic fractures in 50 patients were reviewed to determine the relative frequency of fracture types, complication rates, and clinical outcomes. Patient data were obtained through review of the clinical notes and individual patient follow up. Clinical outcomes were evaluated using the Oxford Hip Score (OHS) and Harris Hip Score (HHS).

The fractures were classified using the Vancouver system, the majority of which were type B 1 (20) or type B2 (10). The mean time to union for all fracture types was 4.6 months. A high non-union rate was seen amongst fractures fixed operatively. Fifteen percent of fractures went on to develop loosening following treatment, suggesting under-recognition at the time of injury. The average HHS was 73.1 and OHS 30.3 for all fracture types, at a mean follow up of 3.3 years. Of the 15 patients treated with revision surgery, the most common complication was dislocation (27%).

Treatment of patients with peri-prosthetic fractures requires recognition of the challenging nature of these injuries, their associated poor prognosis, and high complication rate.

Background: The main aim of this study was to compare the effectiveness of a brief intervention based on cognitive-behavioural principles (Solution Finding Approach – SFA) with the McKenzie approach (McK). A secondary aim was to determine if there were any clinical characteristics that distinguished patients who responded best to the McKenzie method.

Methods: Eligible patients who were referred by GPs to physiotherapy departments in the UK with neck or back pain were randomly allocated to McK (n= 161) or to SFA (n=154) and their outcome compared at 6 weeks, 6 and 12 months. In addition, putative predictors within the McKenzie group were compared using univariate analysis to examine the relationship between variables and outcomes. Significant variables were assessed using multiple logistic regression analyses.

Results: Both groups demonstrated modest improvements in outcomes. There were no statistically significant differences in outcomes, except 2 small but significant differences at 6 weeks. At 6 weeks, patient satisfaction was greater for McK (median 90% compared with 70% for SFA). The number of treatment successes in the McK group depended upon the definition used, but were limited. Less chronic back pain (rather than neck pain) in patients demonstrating centralisation responded best.

Conclusion: In the original RCT there were few differences between McK and SFA though modest improvements in both. In a secondary analysis of the results for the McK group there were few treatment successes according to our definition of success; these were most likely to occur in back pain patients with shorter duration symptom who demonstrated centralisation response.

Introduction: Blood management in the perioperative period of the total joint arthroplasty procedure has evolved over the last 3 decades. We performed two separate studies:

1) observational study to analyse surgeon’s and anaesthetist’s attitude to transfusion

Method: 500 orthopaedic surgeons and 336 anaesthetists were surveyed to assess current UK attitudes towards transfusion practice following arthroplasty.

200 patients (88 THR, 99 TKR, 13 hip resurfacing) were evaluated. Blood Hb, hand grip strength and vigour scores using fatigue questionnaire were estimated both preoperatively and at 3 days following surgery. POMS and the required duration of in-patient physiotherapy were also noted. The protocol for blood transfusion was for those with Hb less than 8 g/dL and/or post-operative symptoms attributable to anaemia.

Results: In an uncomplicated patient following total hip arthroplasty, 53.2% of surgeons and 63.1% of anaesthetists would transfuse at or below Hb of 8g/dL. Mean transfusion threshold in surgeons was 8.3g/dL compared to 7.9g/dL for anaesthetists (p< 0.01). 97% of surgeons transfused two or more units compared to 78% anaesthetists (p< 0.01). This threshold Hb increased if patient was symptomatic (surgeons 9.3g/dL, anaesthetists 8.8g/dL, p< 0.05), or if known to have pre-existing ischaemic heart disease (surgeons 9.0g/dL, anaesthetists 9.2g/dL, p< 0.05).

A greater fall in postoperative Hb correlated significantly with a greater reduction in post-operative vigour score (p=0.02). Also a greater fall in vigour score was found to correlate significantly with the duration of in-patient physiotherapy (p< 0.001). A reduction in Hb of > 4g/dL from the pre-operative Hb predicted a significantly higher reduction in vigour score (p=0.03). A weak correlation was seen between a fall in Hb and POMS (p=0.09).

A higher pre-operative Hb did not reduce the required duration of in-patient physiotherapy (p=0.72). There was no correlation between post-operative Hb and POMS (p=0.21) or duration of in-patient physiotherapy (p=0.20).

A higher pre-operative grip strength predicted an early date of discharge by the physiotherapists (p=0.02).

Conclusion: Haemoglobin level below 9g/dL is the most common ‘trigger’ for blood transfusion. Surgeons tend to be more aggressive in their attitude to transfusion. A fall in Hb of more than 4 g/dL has a detrimental effect on post-operative rehabilitation. Pre-operative grip strength measurements are valuable in predicting the rehabilitation potential of patients undergoing lower limb arthroplasty.

Recently, the International Consensus Statement Group reported that mechanical prophylaxis with foot-pumps should be considered “Grade A” recommendation for prevention of deep-vein thrombosis after total hip replacement. Mechanical prophylaxis with foot-pumps provides an interesting alternative to chemical agents in the prevention of thomboembolic disease following major orthopaedic surgery procedures. Recent duplex ultrasound studies have suggested that simultaneous use of graduated compression stockings (GCS) may hinder the pneumatic compression effect of foot pumps. The hypothesis of this prospective study was that the use of foot-pumps without GCS does not affect the efficacy of DVT prophylaxis, and improves patient compliance.

846 consecutive patients admitted at a single institution undergoing total hip (THR) or knee replacement (TKR) were included in the study. The A-V Impulse System® foot-pump units (Orthofix Vascular Novame-dix, Andover, UK) was used in all patients. Forty-six patients discontinued the use of foot-pumps, leaving 400 patients who received foot-pumps in combination with GCS and 400 patients with foot pumps alone.

Eleven patients of the stocking group (2.7%) and 9 patients of the no-stockings group (2.3%) developed postoperative symptomatic DVT (p=0.07). DVT was more frequent in TKR (10 of 364; 2.7%) than in THR (10 of 436; 2.3%). Non-fatal pulmonary embolism occurred in 4 patients out of 20 with symptomatic DVT, 2 each of the stockings and no stockings groups. The foot pump discontinuation rate of patients treated with stockings was 7%, versus 4% of patients treated without stockings (p< 0.05).

In conclusion, management of patients with foot-pumps without GCS does not reduce efficacy of DVT prophylaxis after THR and TKR, and improves patient compliance.

Introduction: Management of periprosthetic fractures following total hip arthroplasty (THA) represents a difficult clinical problem, requiring expertise in both trauma and revision surgery. Estimates of the prevalence of postoperative fracture range from 0.1% to 2.1%, and with rising numbers of patients in the population living with hip prostheses in situ there is evidence that their frequency is increasing. There remains a paucity of data on the functional outcome of these injuries, and the objective of this study was to analyse outcomes for revision THA following periprosthetic fracture, and compare these to elective revision surgery.

Methods: 233 patients (234 hips) undergoing revision THA for femoral fracture were identified from the New Zealand National Registry, and clinical outcomes were measured using Oxford Hip Scores (OHS) completed six months post operatively. A control group of 234 patients undergoing elective revision THA was selected and matched for age, sex, and time since index operation.

Results: Comparative analysis of the registry patients showed clinical outcomes were significantly worse following revision THA for fractured femur than in controls (mean OHS 28.6 vs 23.6, p=0.006), though this difference was not apparent in patients under the age of 65 years (mean OHS 26.1 vs 23.8, p =0.6). A higher mortality rate was found among fracture patients (17.1% versus 10.7 %, p=0.05), and a statistically significant higher number of periprosthetic fracture patients died within 6 months of their surgery in comparison to controls (7.3% versus 0.9%, p=0.003). A higher rate of re-revision was observed in the fracture group (7.7% versus 2.6%, p=0.02).

Conclusions: To our knowledge this study represents the largest comparative series of periprosthetic fractures in THA with functional outcome data yet reported. Management of patients with periprosthetic fractures requires recognition of the challenging nature of these injuries, their associated poor prognosis, and high complication rate.

Microfracture is a stem cell stimulation technique to promote the healing of full thickness articulate cartilage defects

Sixty-six patients have undergone microfracture for full thickness articulate cartilage defects over a five year period. All procedures were performed by one surgeon following the technique of Steadman. All patients were under 46, had an isolated chondral lesion, had a stable well aligned knee and were a minimum of one year post surgery.

Patients were evaluated with a preoperative and follow up IKDC score, WOMAC score, KOOS Score, Tegner activity level and SF 36, VAS pain scores and overall knee function score. Failure was determined by the need for a secondary chondral procedure.

Nine patients failed. Thus the overall success rate was 86%. The failure rate was higher with larger lesions.

There was a significant improvement in IKDC score, WOMAC score, KOOS Score, Tegner activity level and SF 36, VAS pain scores and overall knee function score.

Microfracture has a good success rate in the short to medium term with isolated full thickness articular cartilage lesions in the stable well aligned knee.