Objectives. The Kaplan-Meier estimation is widely used in orthopedics to calculate the probability of revision surgery. Using data from a long-term follow-up study, we aimed to assess the amount of bias introduced by the Kaplan-Meier estimator in a competing risk setting. Methods. We describe both the Kaplan-Meier estimator and the competing risk model, and explain why the competing risk model is a more appropriate approach to estimate the probability of revision surgery when patients die in a hip revision surgery cohort. In our study, a total of 62 acetabular revisions were performed. After a mean of 25 years, no patients were lost to follow-up, 13 patients had undergone revision surgery and 33 patients died of causes unrelated to their hip. Results. The Kaplan-Meier estimator overestimates the probability of revision surgery in our example by 3%, 11%, 28%, 32% and 60% at five, ten, 15, 20 and 25 years, respectively. As the cumulative incidence of the competing event increases over time, as does the amount of bias. Conclusions. Ignoring competing risks leads to biased estimations of the probability of revision surgery. In order to guide choosing the appropriate statistical analysis in future clinical studies, we propose a flowchart

Extracapsular Hip Fractures (EHF's) are a significant health burden on healthcare services. Optimal treatment is controversial with conflicting evidence being reported. Currently treatment is undertaken with Intramedullary Nail (IMN) or Dynamic Hip Screw (DHS) constructs with a recent increase in IMN use (1). This study aims to conduct a systematic review of Randomised Control Trials published between 2020 and 2023 with particular focus on patient demographics and holistic patient outcomes. Using a unified search-protocol, RCT's published between 2020 and 2023 were collected from CENTRAL, PubMed, MEDLINE and EMBASE. Rayyan software screened duplicates. Using the CASP and Cochrane Risk of Bias Tool papers were critically examined twice, and Blood Loss, Infection and Mobility described the patient journey. Patient demographics were recorded and were contrasted with geographically diverse cohort studies to compare population differences. Parametric tests were used to determine significance levels between population demographics, namely Age and Sex. Eleven papers were included, representing 908 patients (436 Male). The mean age for patients was 64.39. There was considerable risk of bias in 7/11 studies owing to the randomization process and the recording of data. Four Cohort studies were selected for comparison representing 14314 patients. Mean age was significantly different between Cohort Studies and RCT's (Independent T-Test, df 13, t=7.8, p = <0.001, mean difference = 19.251, 95% CI = 13.888, 24.613). This was also true for sex ratios included in the studies (df 13, t = -2.268, p = 0.024, Mean Difference = -0.4884, 95% CI = -0.9702, -0.0066). To conclude, RCT's published in the post COVID-19 era are not representative of patient demographics. This has the potential to provide inaccurate information for implant selection. Additionally further research must be conducted in how to better improve RCT patient inclusion so as to be more representative of patients whilst balancing the risks of operations

The current evidence favors replacement for the treatment of displaced femoral neck fractures in the older patients. Controversies remain whether total hip replacement (THR), or hemiarthroplasty (HA) would result in better outcomes. The purpose of this study is to compare the outcomes, and the complications in patients who underwent THR or HA for displaced femoral neck fractures. There were 345 consecutive patients who had undergone either a THR or HA at a single institution. THR was done in 137, and HA was done in 208 patients, respectively. Standard peri-operative data were collected. The mean values for the data in the THR group are: age 69 years, ASA 2.7, OR time was 99 minutes, estimated blood loss 354 ml, and the length of stay 8 days. The mean values for the data in the HA group are: age 75 years, ASA 3.0, OR time 88 minutes, estimated blood loss 200 ml, and the length of stay 10 days. The overall complications were 8.8% (THR), and 9.1% (HA), respectively. The mortality rates for the patients were: at the 1-year (9.5% THR vs 16.3% HA), at the 3-year (15.3% THR vs 24.0% HA), and at the 5-year (19.7% THR vs 26.9% HA), respectively. Our data demonstrated similar peri-operative data and short-term complications between the two groups. There was a difference in the mortality rates between the two groups at all 3-time intervals following the surgery. This could be a reflection of the patient selection bias for each of the operations

Total hip arthroplasty has been constantly evolving with technological improvements to achieve the best survival rates. Although the new implants are under closer surveillance through processes such as Beyond Compliance, orthopaedic surgeons generally tend to look out for the latest implants with good short-term results and hope for better long-term results for these. We questioned whether such an assumption or bias is valid. We analysed the data of Kaplan-Meier estimates of cumulative revisions of primary hip replacement by fixation, stem/cup brand and bearing combinations from the NJR 19th Annual Report published in September 2022. We performed a univariate linear regression analysis to predict the 10- and 15-year revision rates for these different hip implant combinations from the 3- and 5-year revision rates. Thirty-seven implant combinations had their 15-year revision rates reported and 67 had the 10-year revision rates. The correlation co-efficients were 0.43 and 0.58 for the 3-year and 5-year revision rates against 15-year revision rates. Only 17% of the variance in 15-year revision rates could be predicted by a linear regression model from the 3-year revision rate and 32% from the 5-year revision rate. Corresponding values for the 10-year revision rates were 46% and 67%. 95% prediction intervals for the 15-year revision rate were +/− 3.1% from the 3-year revision rate and +/− 2.8% from the 5-year revision rate. Corresponding values for the 10-year revision rates were +/− 1.3% and +/− 1%. 19 of 37 implant combinations showed 15-year revision rate of more than 4%. Average 3-year and 5-year revision rates for this cohort was 1.0% and 1.42% compared to 1.4% and 1.9% for the rest and the difference was statistically significant. Although average early revision rates showed small but significant difference between the groups with lower and higher 15-year revision rates, the prediction intervals for 15-year revision rates for individual hips based on their 3-year and 5-year revision rates are very wide. Three- and 5-year revision rates for primary total hip replacements are poor predictors of 15-year revision rates

Patients undergoing total hip or knee arthroplasty (THA/TKA) are commonly associated with high pain scores and narcotic use. Duloxetine is effective in relieving chronic pain. The aim of this study was to evaluate the safety and efficacy of duloxetine for pain management following THA/TKA. Five major databases (PubMed, Embase, Scopus, Cochrane, and Web of Science) were searched for randomised controlled trials (RCTs) that compared duloxetine to placebo in patients that underwent THA/TKA. The primary outcome was pain reduction with rest and movement at short-term and long-term time intervals. Secondary outcomes were the use of analgesics, length of stay, and safety profile. The risk of bias was assessed using the Cochrane tool. Data were pooled using RevMan 5.4. The results were reported as mean difference (MD) or standardised MD (SMD) and 95% confidence intervals (CI). Eight RCTs with 767 patients were included. 50.2% (n=385/767) of patients received duloxetine. After one day, duloxetine was superior to the control regarding pain reduction with rest (SMD= −0.22 [−0.41, −0.03], p=0.02) after sensitivity analysis and pain reduction at movement (SMD= −0.39 [−0.55, −0.24], p<0.001). Similarly, after 12 weeks, duloxetine significantly reduced pain with rest (SMD= −0.3 [−0.52, −0.09], p=0.006) and pain with movement (SMD= −0.52 [−0.87, −0.17], p=0.003). In addition, after sensitivity analysis, duloxetine was associated with less analgesic use after one day (MD= −4.65 [−7.3, −2.01], p<0.001) and two days (MD= −5.65 [−10.62, −0.67], p=0.03). Patients who received duloxetine also required fewer analgesics after three days. However, there was no significant difference between the duloxetine and control groups in analgesic use after one week, length of stay, and adverse events. Duloxetine was superior to the placebo regarding short-term and long-term pain reduction with rest and movement following THA/TKA. Duloxetine reduced postoperative analgesic use. There was no significant difference between duloxetine and placebo regarding adverse events and length of stay

In 2022, approximately 60% of inserted cups and stems in Sweden utilized cemented fixation. Two predominant brands, Refobacin Bone Cement R and Palacos R+G, both incorporating gentamicin, were employed in over 90% of primary cemented Total Hip Arthroplasties (THAs) between 2012 and 2022. This study investigates whether the choice between these cement types affects the risk of revision. The five most frequently used cemented cups and the three most common stems were studied. Inclusion criteria encompassed hips with non-tumour diagnoses, operated through a direct lateral or posterior incision, featuring a 28–36 mm metal or ceramic head. Outcomes were assessed for cup revisions (n=55,457 Refobacin, 37,210 Palacos), stem revisions (n=51,732 Refobacin, 30,018 Palacos), and all-cemented THAs with either brand (n=45,265 Refobacin, 26,347 Palacos). Kaplan-Meier life tables and hazard ratios (HR) utilizing Cox regression were computed, adjusting for age, sex, diagnosis, implant type, femoral head size, and material. Over a 10-year period, the cumulative percent revision with Refobacin was consistently higher than Palacos in all three analyses (cups: Refobacin 2.4 (2.3–2.5), Palacos 2.1 (2.0–2.2); stems: Refobacin 2.6 (2.5–2.7), Palacos 2.1 (2,0–2,2); all-cemented: Refobacin 3.2 (2.9–3.5), Palacos 2.9 (2.6–3.2)). Both unadjusted and adjusted HR were 13–25% lower with Palacos. In the analysis of all-cemented THAs, the adjusted HR for Palacos was 0.85 (0.76–0.95). Separating revisions into infectious and non-infectious reasons revealed a lower risk of infectious revisions with Palacos in all three analyses (all-cemented: adjusted HR infection 0.66 (0.56–0.78); non-infectious 1.10 (0.94–1.28)). Hips cemented with Refobacin may face an increased risk of infection, potentially due to a smaller release of antibiotics into surrounding tissues. Unaccounted factors like different mixing systems or unknown biases could also influence outcomes, emphasizing the need for further investigation

Over 8000 total hip arthroplasties (THA) in the UK were revised in 2019, half for aseptic loosening. It is believed that Artificial Intelligence (AI) could identify or predict failing THA and result in early recognition of poorly performing implants and reduce patient suffering. The aim of this study is to investigate whether Artificial Intelligence based machine learning (ML) / Deep Learning (DL) techniques can train an algorithm to identify and/or predict failing uncemented THA. Consent was sought from patients followed up in a single design, uncemented THA implant surveillance study (2010–2021). Oxford hip scores and radiographs were collected at yearly intervals. Radiographs were analysed by 3 observers for presence of markers of implant loosening/failure: periprosthetic lucency, cortical hypertrophy, and pedestal formation. DL using the RGB ResNet 18 model, with images entered chronologically, was trained according to revision status and radiographic features. Data augmentation and cross validation were used to increase the available training data, reduce bias, and improve verification of results. 184 patients consented to inclusion. 6 (3.2%) patients were revised for aseptic loosening. 2097 radiographs were analysed: 21 (11.4%) patients had three radiographic features of failure. 166 patients were used for ML algorithm testing of 3 scenarios to detect those who were revised. 1) The use of revision as an end point was associated with increased variability in accuracy. The area under the curve (AUC) was 23–97%. 2) Using 2/3 radiographic features associated with failure was associated with improved results, AUC: 75–100%. 3) Using 3/3 radiographic features, had less variability, reduced AUC of 73%, but 5/6 patients who had been revised were identified (total 66 identified). The best algorithm identified the greatest number of revised hips (5/6), predicting failure 2–8 years before revision, before all radiographic features were visible and before a significant fall in the Oxford Hip score. True-Positive: 0.77, False Positive: 0.29. ML algorithms can identify failing THA before visible features on radiographs or before PROM scores deteriorate. This is an important finding that could identify failing THA early

Implants in total hip replacement (THR) are associated with different clinical and cost-effectiveness profiles,. We estimate the costs and outcomes for NHS patients in the year after THR associated with implant bearing materials using linked routinely collected data. We linked NJR primary elective THR patients for osteoarthritis to HES and National PROMs. We estimated health care costs, health-related quality of life indices, and revision risks, in the year after primary and revision THRs overall. We used generalised linear models adjusting for patient and hospital characteristics and estimated 10-year cumulative probability of revision. We imputed utilities using chained equations for half the sample with missing PROMS. We linked 577,973 elective primary THRs and 11,812 subsequent revisions. One year after primary THR, patients with the cemented THRs using cobalt chrome or stainless steel head with HCLPE liner/cup cost the NHS, on average, £13,101 (95%CI £13,080,£13,122), had an average quality-of-life score of 0.788 (95%CI 0.787,0.788), and a 10-year revision probability of 1.9% (95%CI 1.6,2.3). Compared to the reference, patients receiving a cemented THR with delta ceramic head and HCLPE liner/cup, hybrid THR with delta ceramic head and HCLPE liner/cup, and hybrid THR with alumina head and HCLPE liner/cup had lower 1-year costs (-£572 \[95% CI -£775,-£385\], -£346 \[-£501,-£192\], -£371 \[-£574,-£168\] respectively), better quality of life (0.007 \[95% CI 0.003,0.011\], 0.013 \[0.010,0.016\], 0.009 \[0.005,0.013\] respectively), and lower 10-year revision probabilities (1.4% \[1.03,2.0\], 1.5 \[1.3,1.7\], 1.6%\[1.2,2.1\] respectively). Implant bearing materials are associated with varying mean costs and health outcomes after primary THR. Ours is the first study to derive costs and health outcomes from large, linked databases using multiple imputation methods to deal with bias. Our findings are useful for commissioning and procurement decisions and to inform a subsequent cost-effectiveness model with more granular detail on THR implant types

The aim of this study was to systemically review the evidence for the use of intra-operative cell salvage (ICS) among patients undergoing revision hip arthroplasty, and synthesis the available data to quantify any associated reduction in allogeneic blood transfusion. An electronic database search of MEDLINE (PubMed), EMBASE, Scopus and the Cochrane Library was completed from the date of inception to 9. th. February 2021, using a search strategy and protocol created in conjunction with the PRISMA statement. Inclusion criteria were (i) adult patients >18 years, (ii) ICS utilised in one study group, (iii) revision hip arthroplasty performed. Exclusion criteria were (i) pre-donation of red blood cells, (ii) mixed reporting without dedicated subgroup analysis for revision hip arthroplasty. Screening for eligibility, and quality assessment of included studies, was performed independently by two authors (TW and DH), and any disputes settled by third author (AK). Of the 187 records identified, 11 studies were included in the qualitative analysis, and 5 studies suitable for quantitative meta-analysis. Across the included studies there were 1856 participants, with a mean age of 63.86 years and a male: female ratio of 0.90. Quality assessment demonstrated low or medium risk of bias only. For revision hip arthroplasty patients receiving ICS, 37.07% required ABT with a mean transfusion of 1.92 units or 385ml per patient. For patients treated without ICS, 64.58% required ABT with a mean transfusion of 4.02 units or 803ml per patient. This difference achieved statistical significance (p < 0.05). This study has demonstrated a significant reduction in the need for allogenic blood transfusion associated with intra-operative cell salvage use among patients undergoing revision hip arthroplasty. This study therefore supports the routine use of ICS in this patient group. However, a major limitation is the lack of clinical outcomes reported by the available studies. Further research is required to determine whether this effect is associated with sub-groups of revision arthroplasty procedure, and whether ICS impacts clinical outcomes such as length of stay, rehabilitation progress and mortality

Aims. Use of the direct anterior approach (DAA) for total hip arthroplasty (THA) has increased in recent years due to proposed benefits, including a lower risk of dislocation and improved early functional recovery. This study investigates the dislocation rate in a non-selective, consecutive cohort undergoing THA via the DAA without any exclusion or bias in patient selection based on habitus, deformity, age, sex, or fixation method. Methods. We retrospectively reviewed all patients undergoing THA via the DAA between 2011 and 2017 at our institution. Primary outcome was dislocation at minimum two-year follow-up. Patients were stratified by demographic details and risk factors for dislocation, and an in-depth analysis of dislocations was performed. Results. A total of 2,831 hips in 2,205 patients were included. Mean age was 64.9 years (24 to 96), mean BMI was 29.2 kg/m. 2. (15.1 to 53.8), and 1,595 patients (56.3%) were female. There were 11 dislocations within one year (0.38%) and 13 total dislocations at terminal follow-up (0.46%). Five dislocations required revision. The dislocation rate for surgeons who had completed their learning curve was 0.15% compared to 1.14% in those who had not. The cumulative periprosthetic infection and fracture rates were 0.53% and 0.67%, respectively. Conclusion. In a non-selective, consecutive cohort of patients undergoing THA via the DAA, the risk of dislocation is low, even among patients with risk factors for instability. Our data further suggest that the DAA can be safely used in all hip arthroplasty patients without an increased risk of wound complications, fracture, infection, or revision. The inclusion of seven surgeons increases the generalizability of these results. Cite this article: Bone Joint J 2021;103-B(7 Supple B):38–45

Aims. Uncemented metal acetabular components show good osseointegration, but material stiffness causes stress shielding and retroacetabular bone loss. Cemented monoblock polyethylene components load more physiologically; however, the cement bone interface can suffer fibrous encapsulation and loosening. It was hypothesized that an uncemented titanium-sintered monoblock polyethylene component may offer the optimum combination of osseointegration and anatomical loading. Methods. A total of 38 patients were prospectively enrolled and received an uncemented monoblock polyethylene acetabular (pressfit) component. This single cohort was then retrospectively compared with previously reported randomized cohorts of cemented monoblock (cemented) and trabecular metal (trabecular) acetabular implants. The primary outcome measure was periprosthetic bone density using dual-energy x-ray absorptiometry over two years. Secondary outcomes included radiological and clinical analysis. Results. Although there were differences in the number of males and females in each group, no significant sex bias was noted (p = 0.080). Furthermore, there was no significant difference in age (p = 0.910) or baseline lumbar bone mineral density (BMD) (p = 0.998) found between any of the groups (pressfit, cemented, or trabecular). The pressfit implant initially behaved like the trabecular component with an immediate fall in BMD in the inferior and medial regions, with preserved BMD laterally, suggesting lateral rim loading. However, the pressfit component subsequently showed a reversal in BMD medially with recovery back towards baseline, and a continued rise in lateral BMD. This would suggest that the pressfit component begins to reload the medial bone over time, more akin to the cemented component. Analysis of postoperative radiographs revealed no pressfit component subsidence or movement up to two years postoperatively (100% interobserver reliability). Medial defects seen immediately postoperatively in five cases had completely resolved by two years in four patients. Conclusion. Initially, the uncemented monoblock component behaved similarly to the rigid trabecular metal component with lateral rim loading; however, over two years this changed to more closely resemble the loading pattern of a cemented polyethylene component with increasing medial pelvic loading. This indicates that the uncemented monoblock acetabular component may result in optimized fixation and preservation of retroacetabular bone stock. Cite this article: Bone Joint J 2021;103-B(5):872–880

Aims. It has been suggested that the direct anterior approach (DAA) should be used for total hip arthroplasty (THA) instead of the posterior approach (PA) for better early functional outcomes. We conducted a value-based analysis of the functional outcome and associated perioperative costs, to determine which surgical approach gives the better short-term outcomes and lower costs. Methods. This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol and the Cochrane Handbook. Several online databases were searched. Non-stratified and stratified meta-analyses were conducted to test the confounding biases in the studies which were included. The mean cost and probability were used to determine the added costs of perioperative services. Results. The DAA group had significantly longer operating times (p < 0.001), reduced length of hospital stay by a mean of 13.4 hours (95% confidence interval (CI) 9.12 to 18; p < 0.001), and greater blood loss (p = 0.030). The DAA group had significantly better functional outcome at three (p < 0.001) and six weeks (p = 0.006) postoperatively according to the Harris Hip Score (HHS). However, there was no significant difference between the groups for the HHS at six to eight weeks (p = 0.230), 12 weeks (p = 0.470), six months (p = 0.740), and one year (p = 0.610), the 12-Item Short Form Survey (SF-12) physical score at six weeks (p = 0.580) and one year (p = 0.360), SF-12 mental score at six weeks (p = 0.170) and one year (p = 0.960), and University of California and Los Angeles (UCLA) activity scale at 12 weeks (p = 0.250). The mean non-stratified and stratified difference in costs for the operating theatre time and blood transfusion were $587.57 (95% CI 263.83 to 1,010.29) to $887.04 (95% CI 574.20 to 1,298.88) and $248.38 (95% CI 1,003.40 to 1,539.90) to $1,162.41 (95% CI 645.78 to 7,441.30), respectively, more for the DAA group. However, the mean differences in costs for the time in hospital were $218.23 and $192.05, respectively, less for the DAA group. Conclusion. The use of the DAA, rather than the PA, in THA has earlier benefits for function and pain. However, these are short-lasting, with no significant differences seen at later intervals. In addition the limited benefits were obtained with higher cumulative costs for DAA. Cite this article: Bone Joint J 2021;103-B(6):1078–1087

Aims. A proximal femur fracture (PFF) is a common orthopaedic presentation, with an incidence of over 25,000 cases reported in the Australian and New Zealand Hip Fracture Registry (ANZHFR) in 2018. Hip fractures are known to have high mortality. The purpose of this study was to determine the utility of the Clinical Frailty Scale (CFS) in predicting 30-day and one-year mortality after a PFF in older patients. Methods. A retrospective review of all fragility hip fractures who met the inclusion/exclusion criteria of the ANZHFR between 2017 and 2018 was undertaken at a single large volume tertiary hospital. There were 509 patients included in the study with one-year follow-up obtained in 502 cases. The CFS was applied retrospectively to patients according to their documented pre-morbid function and patients were stratified into five groups according to their frailty score. The groups were compared using t-test, analysis of variance (ANOVA), and the chi-squared test. The discriminative ability of the CFS to predict mortality was then compared with American Society of Anaesthesiologists (ASA) classification and the patient’s chronological age. Results. A total of 38 patients were deceased at 30 days and 135 patients at one year. The 30-day mortality rate increased from 1.3% (CFS 1 to 3; 1/80) to 14.6% (CFS ≥ 7; 22/151), and the one-year mortality increased from 3.8% (CFS 1 to 3; 3/80) to 41.7% (CFS ≥ 7; 63/151). The CFS was demonstrated superior discriminative ability in predicting mortality after PFF (area under the curve (AUC) 0.699; 95% confidence interval (CI) 0.651 to 0.747) when compared with the ASA (AUC 0.634; 95% CI 0.576 to 0.691) and chronological age groups (AUC 0.585; 95% CI 0.523 to 0.648). Conclusion. The CFS demonstrated utility in predicting mortality after PFF fracture. The CFS can be easily performed by non-geriatricians and may help to reduce age related bias influencing surgical decision making. Cite this article: Bone Joint Open 2020;1-8:443–449

Introduction. Quality measures play a substantial role in the Centers for Medicare and Medicaid Services' hospital payment and public reporting programs. The purpose of this study was to assess whether public measurement of total hip and knee arthroplasty risk-standardized readmission (RSRRs) and complication rates (RSCRs) was temporally associated with decreasing rates of adverse outcomes among Medicare beneficiaries. Methods. We evaluated annual trends in hospital-level risk-standardized complication and readmission rates in the fiscal years 2010–11 and 2016–17 for patients undergoing hospital-based inpatient hip/knee replacement procedures. We calculated hospital-level rates using the same measures and methodology used in public reporting. We examined annual trends in the distribution of hospital-level outcomes through density plots (similar to histograms). Results. Both rates of and variation in the complication and readmission outcomes declined steadily between 2010–11 and 2016–17. We noted a 33% relative reduction in hospital-level risk-standardized complication rates (RSCRs) and 25% relative reduction in hospital-level risk-standardized readmission rates (RSRRs). The interquartile range of RSCRs decreased by 18% (relative reduction) and of RSRRs decreased by 34% (relative reduction). Risk variable frequency in complication and readmission models did not systematically change over time, suggesting no evidence of widespread bias or up-coding. Conclusion. This study demonstrates that hospital-level complication and readmission rates after hip/knee replacements and variation in hospital-level performance declined following the start of public reporting and financial incentives associated with measurement. The consistent decreasing trend in rates of and variation outcomes suggests steady improvements and greater consistency among hospitals in clinical outcomes for hip/knee replacement patients in the years 2016–17 compared to 2010–11. While improvements in surgical practices and care coordination may partially account for these findings, the precise influence of measure public reporting on clinical outcomes is difficult to ascertain. Interactions between public reporting, payment, and hospital coding practices are complex and require continued study

Aims. Vancouver type B periprosthetic femoral fractures (PFF) are challenging complications after total hip arthroplasty (THA), and some treatment controversies remain. The objectives of this study were: to evaluate the short-to-mid-term clinical outcomes after treatment of Vancouver type B PFF and to compare postoperative outcome in subgroups according to classifications and treatments; to report the clinical outcomes after conservative treatment; and to identify risk factors for postoperative complications in Vancouver type B PFF. Methods. A total of 97 consecutive PPFs (49 males and 48 females) were included with a mean age of 66 years (standard deviation (SD) 14.9). Of these, 86 patients were treated with surgery and 11 were treated conservatively. All living patients had a minimum two-year follow-up. Patient demographics details, fracture healing, functional scores, and complications were assessed. Clinical outcomes between internal fixation and revisions in patients with or without a stable femoral component were compared. Conservatively treated PPFs were evaluated in terms of mortality and healing status. A logistic regression analysis was performed to identify risk factors for complications. Results. In surgically treated patients, all fractures united and nine complications were identified. The mean postoperative Visual Analogue Scale (VAS) for pain was 1.5 (SD 1.3), mean Parker Mobility Score (PMS) was 6.5 (SD 2.4), and mean Harris Hip Score (HHS) was 79.4 (SD 16.2). Among type B2 and type B3 fractures, patients treated with internal fixation had significantly lower PMS (p = 0.032) and required a longer time to heal (p = 0.012). In conservatively treated patients, one-year mortality rate was 36.4% (4/11), and two patients ultimately progressed to surgery. Young age (p = 0.039) was found to be the only risk factor for complications. Conclusion. The overall clinical outcome among Vancouver type B PFF was satisfactory. However, treatment with internal fixation in type B2 and B3 fractures had a significantly longer time to heal and lower mobility than revision cases. Conservative treatment was associated with high rates of early mortality and, in survivors, nonunion. This probably reflects our selection bias in undertaking surgical intervention. In our whole cohort, younger patient age was a risk factor for postoperative complications in Vancouver type B PFF. Cite this article: Bone Joint J 2020;102-B(3):293–300

Osteoarthritis of the hip is common and the mainstay of surgical treatment for end-stage disease is total hip replacement. There are few RCTs comparing long-term outcomes between prostheses; therefore, surgeons and patients are reliant on single-centre case-series and recently, analysis of joint registries, when making evidence-based implant choices. We conducted a systematic review, conforming to PRISMA, of Medline and Embase in September 2017. Single-centre case-series and papers analysing registries were included. Series looking at disease-specific cohorts (other than OA), under 15 years follow-up or lacking survival analyses were excluded. Resurfacings, revisions and complex-primaries were also excluded. 2750 abstracts were screened, resulting in 299 full-text articles. Following full review 124 articles were excluded and 21 series added from references, resulting in 150 analyses of individual prostheses/constructs and 12 papers from registries. We also analysed annual reports of registries. Registry data indicated cemented prostheses tended to better outcomes at late follow-ups, whereas case-series showed cementless prostheses tended to have better survival past 15 years with revision for any reason (of stem, cup or either component) as the end-point. The discrepancy between results from registry data and single-centre case series is stark, and whilst the reasons for these differences may be multifactorial, single-centre case-series included in this review often lacked sufficient power to provide precise estimates of survival. This is contrasted to data from registries, which tended to have far greater numbers from multiple centres, allowing results to be generalised to the population. The difference between these two modes of analysis suggests bias exists in selection and outcomes from single-centre series. The varied quality of reporting in case-series make it difficult for a reader to adequately assess bias, and accurately inform contemporary decision making. Surgeons and patients should be cautious when interpreting single-centre case series and systems relying on data generated from them

Introduction. Instability remains a common complication following total hip arthroplasty (THA) and continues to account for the highest percentage of revisions in numerous registries. Many risk factors have been described, yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to apply a machine learning algorithm to develop a patient-specific risk score capable of dynamic adjustment based on operative decisions. Methods. 22,086 THA performed between 1998–2018 were evaluated. 632 THA sustained a postoperative dislocation (2.9%). Patients were robustly characterized based on non-modifiable factors: demographics, THA indication, spinal disease, spine surgery, neurologic disease, connective tissue disease; and modifiable operative decisions: surgical approach, femoral head size, acetabular liner (standard/elevated/constrained/dual-mobility). Models were built with a binary outcome (event/no event) at 1-year and 5-year postoperatively. Inverse Probability Censoring Weighting accounted for censoring bias. An ensemble algorithm was created that included Generalized Linear Model, Generalized Additive Model, Lasso Penalized Regression, Kernel-Based Support Vector Machines, Random Forest and Optimized Gradient Boosting Machine. Convex combination of weights minimized the negative binomial log-likelihood loss function. Ten-fold cross-validation accounted for the rarity of dislocation events. Results. The 1-year model achieved an area under the curve (AUC)=0.63, sensitivity=70%, specificity=50%, positive predictive value (PPV)=3% and negative predictive value (NPV)=99%. The 5-year model achieved an AUC=0.62, sensitivity=69%, specificity=51%, PPV=7% and NPV=97%. All cohort-level accuracy metrics performed better than chance. The two most influential predictors in the model were surgical approach and acetabular liner. Conclusions. This machine learning algorithm demonstrates high sensitivity and NPV, suggesting screening tool utility. The model is strengthened by a multivariable dataset portending differential dislocation risk. Two modifiable variables (approach and acetabular liner) were the most influential in dislocation risk. Calculator utilization in “app” form could enable individualized risk prognostication. Furthermore, algorithm development through machine learning facilitates perpetual model performance enhancement with future data input

Introduction. The proportion of arthroplasties performed in the ambulatory setting has increased substantially. However, concerns remain regarding whether same-day discharge may increase the risk of complications. The purpose of this study was to compare 90-day outcomes between inpatients and patients having surgery at an ambulatory surgery center (ASC). Methods. Among a single-surgeon cohort of 721 patients who underwent arthroplasty at a free-standing ASC, 611 (84.7%) were matched one-to-one to inpatients based on age, gender, American Society of Anesthesiologists (ASA) score, and Body Mass Index (110 patients could not be adequately matched). The cohort included 208 total hip arthroplasties (34.0%), 196 total knee arthroplasties (32.1%), 178 unicompartmental knee arthroplasties (29.1%), 25 hip resurfacings (4.1%), two revision hip arthroplasties (0.3%) and two revision knee arthroplasties (0.3%). Post-operative outcomes including readmissions, reoperations, unplanned clinic visits, emergency department visits, and complications were compared. Complications were classified as either major (i.e. death, periprosthetic joint infection, pulmonary embolism) or as minor (i.e. delayed wound healing, rashes, urinary retention). Results. The inpatient and outpatient groups were similar in all demographic variables, reflecting successful matching. The rates of any complications (4.1% outpatient vs. 5.1% inpatient, p=0.41), minor complications (2.6% vs. 3.4%; p=0.40), readmissions (1.6% vs. 2.0%; p= 0.67), reoperations (0.7% vs. 1.1%; p=0.36), and unplanned clinic visits (5.4% vs 6.7%; p=0.34) were all lower amongst the outpatient group but did not reach significance with the sample size studied. The rate of major complications was the same in both groups (1.6% for both; p=1.0) while patients who underwent surgery at an ASC had significantly fewer emergency department visits (1.0% vs. 3.1%; p=0.009). Conclusions. Arthroplasty performed in the ambulatory setting appears to be safe in properly selected patients. However, this finding may be partly due to selection bias and intangible characteristics that were not adequately controlled for through matching

Objectives. The aim of this study was to use registry data to report and compare early patient outcomes following arthroscopic repair or debridement of the acetabular labrum. Methods. Data on adult patients who underwent arthroscopic labral debridement or repair between January 2012 and March 2019 was extracted from the UK Non-Arthroplasty Hip Registry dataset. Patients who underwent microfracture, osteophyte excision or a concurrent extra-articular procedure were excluded. Outcomes comprised EuroQol-5 Dimensions (EQ-5D) index and the International Hip Outcome Tool 12 (iHOT-12), preoperatively and at 6 and 12 months. Results. A total of 3,553 arthroscopies comprising 1,986 labral debridement (56%) and 1,567 labral repairs (44%) were identified. Both groups saw significant (p <0.0001) EQ-5D and iHOT-12 gain compared to pre-operative baseline scores at 6 months (iHOT-12: repair = +27.4 (95%CI 25.2 to 29.5), debridement = +24.8 (95%CI 22.7 to 26.9)) which was maintained at 12 months (repair = +28.3 (95%CI 26.0 to 30.6), debridement = +24.3 (95%CI 22.0 to 26.5)) with improvement being significantly greater in the repair group by 12 months (p = 0.016) including after modelling for patient and surgical factors. Overall, 64% of cases achieved the minimum clinically important difference (MCID) and 47% achieved substantial clinical benefit (SCB: repair = 51%, debridement = 43%, p = 0.005) at 12 months. Significant functional improvement was seen for both genders and in younger and older (>40 years) cohorts. Conclusion. Both labral repair and debridement techniques were successful in significantly improving 12-month outcomes following hip arthroscopy regardless of age or gender. Labral repair was associated with superior outcomes in comparison to debridement. Whilst patient selection is crucial, our findings support the repair of an injured labrum where possible. A multi-centre randomised controlled trial would be the most appropriate next step to overcome bias inherent in the existing literature

Background. The purpose of this study was to report functional outcome scores following arthroscopic acetabular chondral procedures using the U.K. Non-Arthroplasty Hip Registry (NAHR). Methods. Data on adult patients who underwent hip arthroscopy between January 2012 and December 2018 was extracted from the NAHR. Patients who underwent femoral sided chondral procedures were excluded. Patients who underwent osteophyte excision or a concurrent extra-articular procedure were also excluded. Cases were then classified according to the acetabular chondral procedure performed – ‘chondroplasty’, ‘microfracture’ or ‘none’ (no chondral procedure recorded). Outcomes comprised EuroQol-5 Dimensions (EQ-5D) index and the International Hip Outcome Tool 12 (iHOT-12), preoperatively and at 6 and 12 months. Results. A total of 4,978 arthroscopies were identified (chondroplasty 26.4%, microfracture 5.4%, none 68.2%). Patients who underwent microfracture were significantly older (37.9y vs 37.3y) and of higher BMI (26.4 vs 25.8 kg/m2) than patients who underwent chondroplasty. Pre-operative, 6 and 12-month follow-up were available for 77%, 42% and 38% of cases respectively. This registry study found significant clinical improvement in all groups based on arthroscopic chondral procedure following hip arthroscopy. Patients who have microfracture seem to take longer to improve and have lower peak scores as compared with chondroplasty. All groups saw significant (p <0.0001) EQ-5D and iHOT-12 gain compared to pre-operative baseline scores at 6 months which was maintained at 12 months (12 month iHOT-12 gain: chondroplasty = +27.6 (95%CI 25.0 to 30.2), microfracture = +22.6 (95%CI 17.6 to 27.6), none = +25.4 (23.8 to 27.0)). There were no statistically significant between group differences in iHOT-12 gain. Comparing <40y vs >40y age groups, all saw significant improvements in baseline scores maintained up to 12 months however patients over 40y were slower to improve, particularly in microfracture with significantly poorer iHOT-12 gain at 6 months in comparison to patients under 40y but significance was lost by 12 months. Conclusion. Whilst patient selection is crucial (and we acknowledge selection bias as a key limitation), all three chondral procedures were effective at improving patient outcomes for both younger and older patients