Aims. This is a multicentre, non-inventor, prospective observational study of 503 INFINITY fixed bearing total ankle arthroplasties (TAAs). We report our early experience, complications, and radiological and functional outcomes. Methods. Patients were recruited from 11 specialist centres between June 2016 and November 2019. Demographic, radiological, and functional outcome data (Ankle Osteoarthritis Scale, Manchester Oxford Questionnaire, and EuroQol five-dimension five-level score) were collected preoperatively, at six months, one year, and two years. The Canadian Orthopaedic Foot and Ankle Society (COFAS) grading system was used to stratify deformity. Early and late complications and reoperations were recorded as adverse events. Radiographs were assessed for lucencies, cysts, and/or subsidence. Results. In all, 500 patients reached six-month follow-up, 420 reached one-year follow-up, and 188 reached two-year follow-up. The mean age was 67.8 years (23.9 to 88.5). A total of 38 patients (7.5%) presented with inflammatory arthritis. A total of 101 (20.0%) of implantations used patient-specific instrumentation; 167 patients (33.1%) underwent an additional procedure at the time of surgery. A total of seven patients died of unrelated causes, two withdrew, and one was lost to follow-up. The mean follow-up was 16.2 months (6 to 36). There was a significant improvement from baseline across all functional outcome scores at six months, one, and two years. There was no significant difference in outcomes with the use of patient-specific instrumentation, type of arthritis, or COFAS type. Five (1.0%) implants were revised. The overall complication rate was 8.8%. The non-revision reoperation rate was 1.4%. The 30-day readmission rate was 1.2% and the one-year mortality 0.74%. Conclusion. The early experience and complications reported in this study support the current use of the INFINITY TAA as a safe and effective implant in the treatment of end-stage ankle arthritis. Cite this article: Bone Joint J 2021;103-B(7):1270–1276

Aims. Although total knee arthroplasty (TKA) is a highly successful procedure, about 20% of patients remain dissatisfied postoperatively. This proportion is derived from dichotomous models of the assessment of surgical success or failure, which may not reflect the spectrum of outcomes. The aim of this study was to explore differing responses to surgery, and assess whether there are distinct groups of patients with differing patterns of outcome. Methods. This was a secondary analysis of a UK multicentre TKA longitudinal cohort study. We used a group-based trajectory modelling analysis of Oxford Knee Score (OKS) in the first year following surgery with longitudinal data involving five different timepoints and multiple predictor variables. Associations between the derived trajectory groups and categorical baseline variables were assessed, and predictors of trajectory group membership were identified using Poisson regression and multinomial logistic regression, as appropriate. The final model was adjusted for sociodemographic factors (age, sex) and baseline OKS. Results. Data from 731 patients were available for analysis. Three distinct trajectories of outcome were identified: “poor” 14.0%, “modest” 39.1%, and “good” 46.9%. The predicted probability of membership for patients assigned to each trajectory group was high (0.89 to 0.93). Preoperative mental, physical health, and psychosocial factors determined which trajectory is likely to be followed. Poor responders were characterized by a comparatively small number of factors, preoperative expectations of pain and limitations, coping strategies, and a lower baseline physical health status, while the good responders were characterized by a combination of clinical, psychosocial, mental health, and quality of life factors. Conclusion. We identified three distinct response trajectories in patients undergoing TKA. Controlling for baseline score, age, and sex, psychosocial factors such as expectations of pain and limited function and poor coping strategies differentiated the trajectory groups, suggesting a role for preoperative psychosocial support in optimizing the clinical outcome. Cite this article: Bone Joint J 2021;103-B(6):1096–1102

Aims. Open reduction in developmental dysplasia of the hip (DDH) is regularly performed despite screening programmes, due to failure of treatment or late presentation. A protocol for open reduction of DDH has been refined through collaboration between surgical, anaesthetic, and nursing teams to allow same day discharge. The objective of this study was to determine the safety and feasibility of performing open reduction of DDH as a day case. Methods. A prospectively collected departmental database was visited. All consecutive surgical cases of DDH between June 2015 and March 2020 were collected. Closed reductions, bilateral cases, cases requiring corrective osteotomy, and children with comorbidities were excluded. Data collected included demographics, safety outcome measures (blood loss, complications, readmission, reduction confirmation), and feasibility for discharge according to the Face Legs Activity Cry Consolidability (FLACC) pain scale. A satisfaction questionnaire was filled by the carers. Descriptive statistics were used for analysis. Results. Out of 168 consecutive DDH cases, 16 patients fit the inclusion criteria (age range 10 to 26 months, 13 female). Intraoperative blood loss ranged from "minimal" to 120 ml, and there were no complications or readmissions. The FLACC score was 0 for all patients. The carers satisfaction questionnaire expressed high satisfaction from the experience with adequate information and support provided. Conclusion. Open reduction in DDH, without corrective osteotomy, is safe and feasible to be managed as a day case procedure. It requires a clear treatment pathway, analgesia, sufficient counselling, and communication with carers. It is even more important during the COVID-19 pandemic when reduced length of hospital stay is likely to be safer for both patient and their parents. Cite this article: Bone Joint Open 2021;2(4):271–277

Aims. “Get It Right First Time” (GIRFT) and NHS England’s Best Practice Tariff (BPT) have published directives advising that patients over the ages of 65 (GIRFT) and 69 years (BPT) receiving total hip arthroplasty (THA) should receive cemented implants and have brought in financial penalties if this policy is not observed. Despite this, worldwide, uncemented component use has increased, a situation described as a ‘paradox’. GIRFT and BPT do, however, acknowledge more data are required to support this edict with current policies based on the National Joint Registry survivorship and implant costs. Methods. This study compares THA outcomes for over 1,000 uncemented Corail/Pinnacle constructs used in all age groups/patient frailty, under one surgeon, with identical pre- and postoperative pathways over a nine-year period with mean follow-up of five years and two months (range: nine months to nine years and nine months). Implant information, survivorship, and regular postoperative Oxford Hip Scores (OHS) were collected and two comparisons undertaken: a comparison of those aged over 65 years with those 65 and under and a second comparison of those aged 70 years and over with those aged under 70. Results. Overall revision rate was 1.3% (13/1,004). A greater number of revisions were undertaken in those aged over 65 years, but numbers were small and did not reach significance. The majority of revisions were implant-independent. Single component analysis revealed a 99.9% and 99.6% survival for the uncemented cup and femoral component, respectively. Mean patient-reported outcome measures (PROMs) improvement for all ages outperformed the national PROMs and a significantly greater proportion of those aged over 65/69 years reached and maintained a meaningful improvement in their OHS earlier than their younger counterparts (p < 0.05/0.01 respectively). Conclusion. This study confirms that this uncemented THA system can be used safely and effectively in patient groups aged over 65 years and those over 69 years, with low complication and revision rates. Cite this article: Bone Jt Open 2021;2(5):293–300

Aims. There is concern that aggressive target pricing in the new Bundled Payment for Care Improvement Advanced (BPCI-A) penalizes high-performing groups that had achieved low costs through prior experience in bundled payments. We hypothesize that this methodology incorporates unsustainable downward trends on Target Prices and will lead to groups opting out of BPCI Advanced in favour of a traditional fee for service. Methods. Using the Centers for Medicare and Medicaid Services (CMS) data, we compared the Target Price factors for hospitals and physician groups that participated in both BPCI Classic and BPCI Advanced (legacy groups), with groups that only participated in BPCI Advanced (non-legacy). With rebasing of Target Prices in 2020 and opportunity for participants to drop out, we compared retention rates of hospitals and physician groups enrolled at the onset of BPCI Advanced with current enrolment in 2020. Results. At its peak in July 2015, 342 acute care hospitals and physician groups participated in Lower Extremity Joint Replacement (LEJR) in BPCI Classic. At its peak in March 2019, 534 acute care hospitals and physician groups participated in LEJR in BPCI Advanced. In January 2020, only 14.5% of legacy hospitals and physician groups opted to stay in BPCI Advanced for LEJR. Analysis of Target Price factors by legacy hospitals during both programmes demonstrates that participants in BPCI Classic received larger negative adjustments on the Target Price than non-legacy hospitals. Conclusion. BPCI Advanced provides little opportunity for a reduction in cost to offset a reduced Target Price for efficient providers, as made evident by the 85.5% withdrawal rate for BPCI Advanced. Efficient providers in BPCI Advanced are challenged by the programme’s application of trend and efficiency factors that presumes their cost reduction can continue to decline at the same rate as non-efficient providers. It remains to be seen if reverting back to Medicare fee for service will support the same level of care and quality achieved in historical bundled payment programmes. Cite this article: Bone Joint J 2021;103-B(6 Supple A):119–125

Aims. The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition. Methods. This paper reports the outcome of a project developed by the European Bone and Joint Infection Society (EBJIS), and supported by the Musculoskeletal Infection Society (MSIS) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Implant-Associated Infections (ESGIAI). It comprised a comprehensive review of the literature, open discussion with Society members and conference delegates, and an expert panel assessment of the results to produce the final guidance. Results. This process evolved a three-level approach to the diagnostic continuum, resulting in a definition set and guidance, which has been fully endorsed by EBJIS, MSIS, and ESGIAI. Conclusion. The definition presents a novel three-level approach to diagnosis, based on the most robust evidence, which will be useful to clinicians in daily practice. Cite this article: Bone Joint J 2021;103-B(1):18–25

Aims. Hip fracture is a common condition of the older, frailer person. This population is also at risk from SARS-CoV-2 infection. It is important to understand the impact of coexistent hip fracture and SARS-CoV-2 for informed decision-making at patient and service levels. Methods. We undertook a systematic review and meta-analysis of observational studies of older (> 60 years) people with fragility hip fractures and outcomes with and without SARS-CoV-2 infection during the first wave of the COVID-19 pandemic. The primary outcome was early (30-day or in-hospital) mortality. Secondary outcomes included length of hospital stay and key clinical characteristics known to be associated with outcomes after hip fracture. Results. A total of 14 cohort and five case series studies were included (692 SARS-CoV-2 positive, 2,585 SARS-CoV-2 negative). SARS-CoV-2 infection was associated with an overall risk ratio (RR) for early mortality of 4.42 (95% confidence interval (CI) 3.42 to 5.82). Early mortality was 34% (95% CI 30% to 38%) and 9% (95% CI 8% to 10%) in the infected and noninfected groups respectively. Length of stay was increased in SARS-CoV-2 infected patients (mean difference (MD) 5.2 days (3.2 to 7.2)). Age (MD 1.6 years (0.3 to 2.9)); female sex (RR 0.83 (95% CI 0.65 to 1.05)); admission from home (RR 0.51 (95% CI 0.26 to 1.00)); presence of dementia (RR 1.13 (95% CI 0.94 to 1.43)); and intracapsular fracture (RR 0.89 (95% CI 0.71 to 1.11)) were not associated with SARS-CoV-2 infection. There were statistically, but not clinically, significantly greater Nottingham Hip Fracture Scores in infected compared with non-infected patients (MD 0.7 (0.4 to 0.9)). Conclusion. SARS-CoV-2 infection is associated with worse outcomes after hip fracture. This is not explained by differences in patient characteristics. These data can be used to support informed decision-making and may help track the impact of widespread adoption of system-level and therapeutic changes in management of the COVID-19 pandemic. Cite this article: Bone Jt Open 2021;2(5):314–322

Aims. Limb salvage for pelvic sarcomas involving the acetabulum is a major surgical challenge. There remains no consensus about what is the optimum type of reconstruction after resection of the tumour. The aim of this study was to evaluate the surgical outcomes in these patients according to the methods of periacetabular reconstruction. Methods. The study involved a consecutive series of 122 patients with a periacetabular bone sarcoma who underwent limb-salvage surgery involving a custom-made prosthesis in 65 (53%), an ice-cream cone prosthesis in 21 (17%), an extracorporeal irradiated autograft in 18 (15%), and nonskeletal reconstruction in 18 (15%). Results. The rates of major complications necessitating further surgery were 62%, 24%, 56%, and 17% for custom-made prostheses, ice-cream cone prostheses, irradiated autografts and nonskeletal reconstructions, respectively (p = 0.001). The ten-year cumulative incidence of failure of the reconstruction was 19%, 9%, 33%, and 0%, respectively. The major cause of failure was deep infection (11%), followed by local recurrence (6%). The mean functional Musculoskeletal Tumour Society (MSTS) scores were 59%, 74%, 64%, and 72%, respectively. The scores were significantly lower in patients with major complications than in those without complications (mean 52% (SD 20%) vs 74% (SD 19%); p < 0.001). For periacetabular resections involving the ilium, the mean score was the highest with custom-made prostheses (82% (SD 10%)) in patients without any major complication; however, nonskeletal reconstruction resulted in the highest mean scores (78% (SD 12%)) in patients who had major complications. For periacetabular resections not involving the ilium, significantly higher mean scores were obtained with ice-cream cone prostheses (79% (SD 17%); p = 0.031). Conclusion. Functional outcome following periacetabular reconstruction is closely associated with the occurrence of complications requiring further surgery. For tumours treated with periacetabular and iliac resection, skeletal reconstruction may result in the best outcomes in the absence of complications, whereas nonskeletal reconstruction is a reasonable option if the risk of complications is high. For tumours requiring periacetabular resection without the ilium, reconstruction using an ice-cream cone prosthesis supported by antibiotic-laden cement is a reliable option. Cite this article: Bone Joint J 2021;103-B(4):795–803

Aims. It has previously been shown that higher-volume hospitals have better outcomes following revision total knee arthroplasty (rTKA). We were unable to identify any studies which investigated the effect of surgeon volume on the outcome of rTKA. We sought to investigate whether patients of high-volume (HV) rTKA surgeons have better outcomes following this procedure compared with those of low-volume (LV) surgeons. Methods. This retrospective study involved patients who underwent aseptic unilateral rTKA between January 2016 and March 2019, using the database of a large urban academic medical centre. Surgeons who performed ≥ 19 aseptic rTKAs per year during the study period were considered HV and those who performed < 19 per year were considered LV. Demographic characteristics, surgical factors, and postoperative outcomes were compared between the two groups. Results. A total of 308 rTKAs were identified, 132 performed by HV surgeons and 176 by 22 LV surgeons. The LV group had a significantly greater proportion of non-smokers (59.8% vs 49.2%; p = 0.029). For all types of revision, HV surgeons had significantly shorter mean operating times by 17.75 minutes (p = 0.007). For the 169 full revisions (85 HV, 84 LV), HV surgeons had significantly shorter operating times (131.12 (SD 33.78) vs 171.65 (SD 49.88) minutes; p < 0.001), significantly lower re-revision rates (7.1% vs 19.0%; p = 0.023) and significantly fewer re-revisions (0.07 (SD 0.26) vs 0.29 (SD 0.74); p = 0.017). Conclusion. Patients of HV rTKA surgeons have better outcomes following full rTKA. These findings support the development of revision teams within arthroplasty centres of excellence to offer patients the best possible outcomes following rTKA. Cite this article: Bone Joint J 2021;103-B(6 Supple A):131–136

Aims. Brachial plexus injury (BPI) is an often devastating injury that affects patients physically and emotionally. The vast majority of the published literature is based on surgeon-graded assessment of motor outcomes, but the patient experience after BPI is not well understood. Our aim was to better understand overall life satisfaction after BPI, with the goal of identifying areas that can be addressed in future delivery of care. Methods. We conducted semi-structured interviews with 15 BPI patients after initial nerve reconstruction. The interview guide was focused on the patient’s experience after BPI, beginning with the injury itself and extending beyond surgical reconstruction. Inductive and deductive thematic analysis was used according to standard qualitative methodology to better understand overall life satisfaction after BPI, contributors to life satisfaction, and opportunities for improvement. Results. Among the 15 patients interviewed, the following themes emerged: 1) happiness and life satisfaction were noted despite limitations in physical function; 2) quality of social support influences life satisfaction during recovery from BPI; and 3) social participation and having a sense of purpose impact life satisfaction during recovery from BPI. Conclusion. How patients perceive their BPI treatment and recovery varies widely, and is not directly linked to their self-reported functional outcome. Patients with stronger social circles and activities that give them a sense of fulfillment were more likely to be satisfied with their current status. Evaluating a patient’s social network, goals, and potential supportive adaptations early in the treatment timeline through coordinated multidisciplinary care may improve overall satisfaction during recovery from BPI. Cite this article: Bone Joint Open 2020;2(1):9–15

Aims. Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Two-stage revision has traditionally been considered the gold standard of treatment for established infection, but increasing evidence is emerging in support of one-stage exchange for selected patients. The objective of this study was to determine the outcomes of single-stage revision TKA for PJI, with mid-term follow-up. Methods. A total of 84 patients, with a mean age of 68 years (36 to 92), underwent single-stage revision TKA for confirmed PJI at a single institution between 2006 and 2016. In all, 37 patients (44%) were treated for an infected primary TKA, while the majority presented with infected revisions: 31 had undergone one previous revision (36.9%) and 16 had multiple prior revisions (19.1%). Contraindications to single-stage exchange included systemic sepsis, extensive bone or soft-tissue loss, extensor mechanism failure, or if primary wound closure was unlikely to be achievable. Patients were not excluded for culture-negative PJI or the presence of a sinus. Results. Overall, 76 patients (90.5%) were infection-free at a mean follow-up of seven years, with eight reinfections (9.5%). Culture-negative PJI was not associated with a higher reinfection rate (p = 0.343). However, there was a significantly higher rate of recurrence in patients with polymicrobial infections (p = 0.003). The mean Oxford Knee Score (OKS) improved from 18.7 (SD 8.7) preoperatively to 33.8 (SD 9.7) at six months postoperatively (p < 0.001). The Kaplan-Meier implant survival rate for all causes of reoperation, including reinfection and aseptic failure, was 95.2% at one year (95% confidence interval (CI) 87.7 to 98.2), 83.5% at five years (95% CI 73.2 to 90.3), and 78.9% at 12 years (95% CI 66.8 to 87.2). Conclusion. One-stage exchange, using a strict debridement protocol and multidisciplinary input, is an effective treatment option for the infected TKA. This is the largest single-surgeon series of consecutive cases reported to date, with broad inclusion criteria. Cite this article: Bone Jt Open 2021;2(5):305–313

Aims. Removal of infected components and culture-directed antibiotics are important for the successful treatment of chronic periprosthetic joint infection (PJI). However, as many as 27% of chronic PJI patients yield negative culture results. Although culture negativity has been thought of as a contraindication to one-stage revision, data supporting this assertion are limited. The aim of our study was to report on the clinical outcomes for one-stage and two-stage exchange arthroplasty performed in patients with chronic culture-negative PJI. Methods. A total of 105 consecutive patients who underwent revision arthroplasty for chronic culture-negative PJI were retrospectively evaluated. One-stage revision arthroplasty was performed in 30 patients, while 75 patients underwent two-stage exchange, with a minimum of one year's follow-up. Reinfection, re-revision for septic and aseptic reasons, amputation, readmission, mortality, and length of stay were compared between the two treatment strategies. Results. The patient demographic characteristics did not differ significantly between the groups. At a mean follow-up of 4.2 years, the treatment failure for reinfection for one-stage and two-stage revision was five (16.7%) and 15 patients (20.0%) (p = 0.691), and for septic re-revision was four (13.3%) and 11 patients (14.7%) (p = 0.863), respectively. No significant differences were observed between one-stage and two-stage revision for 30- 60- and 90-day readmissions (10.0% vs 8.0%; p = 0.714; 16.7% vs 9.3%; p = 0.325; and 26.7% vs 10.7%; p = 0.074), one-year mortality (3.3% vs 4.0%; p > 0.999), and amputation (3.3% vs 1.3%; p = 0.496). Conclusion. In this non-randomized study, one-stage revision arthroplasty demonstrated similar outcomes including reinfection, re-revision, and readmission rates for the treatment of chronic culture-negative PJI after TKA and THA compared to two-stage revision. This suggests culture negativity may not be a contraindication to one-stage revision arthroplasty for chronic culture-negative PJI in selected patients. Cite this article: Bone Joint J 2021;103-B(3):515–521

Aims. Aneurysmal bone cysts (ABCs) are locally aggressive lesions typically found in the long bones of children and adolescents. A variety of management strategies have been reported to be effective in the treatment of these lesions. The purpose of this review was to assess the effectiveness of current strategies for the management of primary ABCs of the long bones. Methods. A systematic review of the published literature was performed to identify all articles relating to the management of primary ABCs. Studies required a minimum 12-month follow-up and case series reporting on under ten participants were not included. Results. A total of 28 articles meeting the eligibility criteria were included in this review, and all but one were retrospective in design. Due to heterogeneity in study design, treatment, and outcome reporting, data synthesis and group comparison was not possible. The most common treatment option reported on was surgical curettage with or without a form of adjuvant therapy, followed by injection-based therapies. Of the 594 patients treated with curettage across 17 studies, 86 (14.4%) failed to heal or experienced a recurrence. Similar outcomes were reported for 57 (14.70%) of the 387 patients treated with injection therapy across 12 studies. Only one study directly compared curettage with injection therapy (polidocanol), randomizing 94 patients into both treatment groups. This study was at risk of bias and provided low-quality evidence of a lack of difference between the two interventions, reporting success rates of 93.3% and 84.8% for injection and surgical treatment groups, respectively. Conclusion. While both surgery and sclerotherapy are widely implemented for treatment of ABCs, there is currently no good quality evidence to support the use of one option over the other. There is a need for prospective multicentre randomized controlled trials (RCTs) on interventions for the treatment of ABCs. Cite this article: Bone Jt Open 2021;2(2):125–133

Aims. We report the medium-term outcomes of a consecutive series of 118 Zenith total ankle arthroplasties (TAAs) from a single, non-designer centre. Methods. Between December 2010 and May 2016, 118 consecutive Zenith prostheses were implanted in 114 patients. Demographic, clinical, and patient-reported outcome measures (PROMs) data were collected. The endpoint of the study was failure of the implant requiring revision of one or all of the components. Kaplan-Meier survival curves were generated with 95% confidence intervals (CIs) and the rate of failure calculated for each year. Results. Eight patients (ten ankles) died during follow-up, but none required revision. Of the surviving 106 patients (108 ankles: rheumatoid arthritis (RA), n = 15; osteoarthritis (OA), n = 93), 38 were women and 68 were men, with a mean age of 68.2 years (48 to 86) at the time of surgery. Mean follow-up was 5.1 years (2.1 to 9.0). A total of ten implants failed (8.5%), thus requiring revision. The implant survival at seven years, using revision as an endpoint, was 88.2% (95% CI 100% to 72.9%). There was a mean improvement in Manchester-Oxford Foot and Ankle Questionnaire (MOXFQ) from 85.0 to 32.8 and visual analogue scale (VAS) scores from 7.0 to 3.2, and overall satisfaction was 89%. The three commonest complications were malleolar fracture (14.4%, n = 17), wound healing (13.6%, n = 16), and superficial infection (12.7%, n = 15). The commonest reason for revision was aseptic loosening. No patients in our study were revised for deep infection. Conclusion. Our results show that Zenith survival rates are comparable with those in the literature for other implants and in the National Joint Registry (NJR). Overall patient satisfaction was high as were functional outcomes. However, the data highlight potential complications associated with this surgery. The authors believe that these figures support ankle arthroplasty as an option in the treatment of ankle arthritis. Cite this article: Bone Joint J 2021;103-B(4):696–703

Aims. The aim of this study was to explore why some calcar screws are malpositioned when a proximal humeral fracture is treated by internal fixation with a locking plate, and to identify risk factors for this phenomenon. Some suggestions can be made of ways to avoid this error. Methods. We retrospectively identified all proximal humeral fractures treated in our institution between October 2016 and October 2018 using the hospital information system. The patients’ medical and radiological data were collected, and we divided potential risk factors into two groups: preoperative factors and intraoperative factors. Preoperative factors included age, sex, height, weight, body mass index, proximal humeral bone mineral density, type of fracture, the condition of the medial hinge, and medial metaphyseal head extension. Intraoperative factors included the grade of surgeon, neck-shaft angle after reduction, humeral head height, restoration of medial support, and quality of reduction. Adjusted binary logistic regression and multivariate logistic regression models were used to identify pre- and intraoperative risk factors. Area under the curve (AUC) analysis was used to evaluate the discriminative ability of the multivariable model. Results. Data from 203 patients (63 males and 140 females) with a mean age of 62 years (22 to 89) were analyzed. In 49 fractures, the calcar screw was considered to be malpositioned; in 154 it was in the optimal position. The rate of malpositioning was therefore 24% (49/203). No preoperative risk factor was found for malpositioning of the calcar screws. Only the neck-shaft angle was found to be related to the risk of screw malpositioning in a multivariate model (with an AUC of 0.72). For the fractures in which the neck-shaft angle was reduced to between 130° and 150°, 91% (133/46) of calcar screws were in the optimal position. Conclusion. The neck-shaft angle is the key factor for the appropriate positioning of calcar screws when treating a proximal humeral fracture with a locking plate. We recommend reducing the angle to between 130° and 150°. Cite this article: Bone Joint J 2020;102-B(12):1629–1635

Aims

Ankle fractures are common, mainly affecting adults aged 50 years and over. To aid recovery, some patients are referred to physiotherapy, but referral patterns vary, likely due to uncertainty about the effectiveness of this supervised rehabilitation approach. To inform clinical practice, this study will evaluate the effectiveness of supervised versus self-directed rehabilitation in improving ankle function for older adults with ankle fractures.

Aims

Machine-learning (ML) prediction models in orthopaedic trauma hold great promise in assisting clinicians in various tasks, such as personalized risk stratification. However, an overview of current applications and critical appraisal to peer-reviewed guidelines is lacking. The objectives of this study are to 1) provide an overview of current ML prediction models in orthopaedic trauma; 2) evaluate the completeness of reporting following the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement; and 3) assess the risk of bias following the Prediction model Risk Of Bias Assessment Tool (PROBAST) tool.

Aims

Perthes' disease (PD) is a relatively rare syndrome of idiopathic osteonecrosis of the proximal femoral epiphysis. Treatment for Perthes' disease is controversial due to the many options available, with no clear superiority of one treatment over another. Despite having few evidence-based approaches, many patients with Perthes' disease are managed surgically. Positive outcome reporting, defined as reporting a study variable producing statistically significant positive (beneficial) results, is a phenomenon that can be considered a proxy for the strength of science. This study aims to conduct a systematic literature review with the hypothesis that positive outcome reporting is frequent in studies on the treatment of Perthes' disease.