Aims. The aim of this study was to assess medium-term improvements following total hip arthroplasty (THA), and to evaluate what effect different preoperative Oxford Hip Score (OHS) thresholds for treatment may have on patients’ access to THA and outcomes. Methods. Patients undergoing primary THA at our institution with an OHS both preoperatively and at least four years postoperatively were included. Rationing thresholds were explored to identify possible deprivation of OHS improvement. Results. Overall, 2,341 patients were included. Mean OHS was 19.7 (SD 8.2) preoperatively and 39.7 (SD 9.8) at latest follow-up. An improvement of at least eight-points, the minimally important change (MIC), was seen in 2,072 patients (88.5%). The mean improvement was 20.0 points (SD 10.5). If a rationing threshold of OHS of 20 points had been enforced, 90.8% of those treated would have achieved the MIC, but only 54.3% of our cohort would have had access to surgery; increasing this threshold to 32 would have enabled 89.5% of those treated to achieve the MIC while only depriving 6.5% of our cohort. The ‘rationed’ group of OHS > 20 had significantly better OHS at latest follow-up (42.6 vs 37.3; p < 0.001), while extending the rationing threshold above 32 showed postoperative scores were more significantly affected by the ceiling effect of the OHS. Conclusion. The OHS was not designed as a tool to ration healthcare, but if it had been used at our institution for this cohort, applying an OHS threshold of 20 to routine THA access would have excluded nearly half of patients from having a THA; a group in which over 85% had a significant improvement in OHS. Where its use for rationing is deemed necessary, use of a higher threshold may be more appropriate to ensure a better balance between patient access to treatment and chances of achieving good to excellent outcomes. Cite this article: Bone Jt Open 2022;3(3):196–204

Aims. Glenoid bone loss is a significant problem in the management of shoulder instability. The threshold at which the bone loss is considered “critical” requiring bony reconstruction has steadily dropped and is now approximately 15%. This necessitates accurate measurement in order that the correct operation is performed. CT scanning is the most commonly used modality and there are a number of techniques described to measure the bone loss however few have been validated. The aim of this study was to assess the accuracy of the most commonly used techniques for measuring glenoid bone loss on CT. Methods. Anatomically accurate models with known glenoid diameter and degree of bone loss were used to determine the mathematical and statistical accuracy of six of the most commonly described techniques (relative diameter, linear ipsilateral circle of best fit (COBF), linear contralateral COBF, Pico, Sugaya, and circle line methods). The models were prepared at 13.8%, 17.6%, and 22.9% bone loss. Sequential CT scans were taken and randomized. Blinded reviewers made repeated measurements using the different techniques with a threshold for theoretical bone grafting set at 15%. Results. At 13.8%, only the Pico technique measured under the threshold. At 17.6% and 22.9% bone loss all techniques measured above the threshold. The Pico technique was 97.1% accurate, but had a high false-negative rate and poor sensitivity underestimating the need for grafting. The Sugaya technique had 100% specificity but 25% of the measurements were incorrectly above the threshold. A contralateral COBF underestimates the area by 16% and the diameter by 5 to 7%. Conclusion. No one method stands out as being truly accurate and clinicians need to be aware of the limitations of their chosen technique. They are not interchangeable, and caution must be used when reading the literature as comparisons are not reliable. Cite this article: Bone Jt Open 2023;4(7):478–489

Aims. To evaluate mid-to long-term patient-reported outcome measures (PROMs) of endoprosthetic reconstruction after resection of malignant tumours arising around the knee, and to investigate the risk factors for unfavourable PROMs. Methods. The medical records of 75 patients who underwent surgery between 2000 and 2020 were retrospectively reviewed, and 44 patients who were alive and available for follow-up (at a mean of 9.7 years postoperatively) were included in the study. Leg length discrepancy was measured on whole-leg radiographs, and functional assessment was performed with PROMs (Toronto Extremity Salvage Score (TESS) and Comprehensive Outcome Measure for Musculoskeletal Oncology Lower Extremity (COMMON-LE)) with two different aspects. The thresholds for unfavourable PROMs were determined using anchor questions regarding satisfaction, and the risk factors for unfavourable PROMs were investigated. Results. The thresholds for favourable TESS and COMMON were 64.8 and 70.4 points, respectively. Multivariate analysis showed that age at surgery (p = 0.004) and postoperative leg length discrepancy (p = 0.043) were significant risk factors for unfavourable TESS results, while age at surgery (p < 0.001) was a significant risk factor for unfavourable COMMON-LE results. Following receiver operating characteristic analysis, the threshold for both TESS and COMMON-LE was 29 years of age at surgery. Additionally, a leg length discrepancy of 8.2 mm was the threshold for unfavourable TESS. Conclusion. Patients aged > 29 years at the time of surgery require appropriate preoperative counselling and adequate postoperative physical and socioemotional support. Reconstruction equivalent to the length of the resected bone can reduce the risk of functional disabilities in daily living. Cite this article: Bone Jt Open 2023;4(12):906–913

Aims. The rationale for exacting restoration of skeletal anatomy after unstable ankle fracture is to improve outcomes by reducing complications from malunion; however, current definitions of malunion lack confirmatory clinical evidence. Methods. Radiological (absolute radiological measurements aided by computer software) and clinical (clinical interpretation of radiographs) definitions of malunion were compared within the Ankle Injury Management (AIM) trial cohort, including people aged ≥ 60 years with an unstable ankle fracture. Linear regressions were used to explore the relationship between radiological malunion (RM) at six months and changes in function at three years. Function was assessed with the Olerud-Molander Ankle Score (OMAS), with a minimal clinically important difference set as six points, as per the AIM trial. Piecewise linear models were used to investigate new radiological thresholds which better explain symptom impact on ankle function. Results. Previously described measures of RM and surgeon opinion of clinically significant malunion (CSM) were shown to be related but with important differences. CSM was more strongly related to outcome (-13.9 points on the OMAS; 95% confidence interval (CI) -21.9 to -5.4) than RM (-5.5 points; 95% CI -9.8 to -1.2). Existing malunion thresholds for talar tilt and tibiofibular clear space were shown to be slightly conservative; new thresholds which better explain function were identified (talar tilt > 2.4°; tibiofibular clear space > 6 mm). Based on this new definition the presence of RM had an impact on function, which was statistically significant, but the clinical significance was uncertain (-9.1 points; 95% CI -13.8 to -4.4). In subsequent analysis, RM of a posterior malleolar fracture was shown to have a statistically significant impact on OMAS change scores, but the clinical significance was uncertain (-11.6 points; 95% CI -21.9 to -0.6). Conclusion. These results provide clinical evidence which supports the previously accepted definitions. Further research to investigate more conservative clinical thresholds for malunion is indicated. Cite this article: Bone Jt Open 2022;3(10):841–849

Aims. To identify the responsiveness, minimal clinically important difference (MCID), minimal clinical important change (MIC), and patient-acceptable symptom state (PASS) thresholds in the 36-item Short Form Health Survey questionnaire (SF-36) (v2) for each of the eight dimensions and the total score following total knee arthroplasty (TKA). Methods. There were 3,321 patients undergoing primary TKA with preoperative and one-year postoperative SF-36 scores. At one-year patients were asked how satisfied they were and “How much did the knee arthroplasty surgery improve the quality of your life?”, which was graded as: great, moderate, little (n = 277), none (n = 98), or worse. Results. Physical function, role limitations due to physical problems (‘role physical’), bodily pain, and the total score SF-36 scores demonstrated the greatest effect sizes (> 0.9). The MCID for each of SF-36 dimensions ranged from 1.7 for role emotional to 6.4 for bodily pain. The MICs for a cohort of patients ranged from -1.0 for general health to 11.1 for bodily pain. The MICs for an individual patient were marginally greater (one to two points) compared to those for a cohort, and ranging from 0.0 for general and mental health to 13.5 for physical function. The lowest PASS score threshold was associated with physical function (> 34 points) whereas the greatest threshold (> 69 points) was associated with mental health. Conclusion. The SF-36 is a responsive tool, and the estimates for MCID, MIC, and PASS thresholds that can be used to power studies, assess whether there has been a meaningful change in patients’ health-related quality of life, and can be used as a marker of achieving patient satisfaction following TKA. Cite this article: Bone Joint Res 2022;11(7):477–483

Aims. The aim of this study was to produce clinical consensus recommendations about the non-surgical treatment of children with Perthes’ disease. The recommendations are intended to support clinical practice in a condition for which there is no robust evidence to guide optimal care. Methods. A two-round, modified Delphi study was conducted online. An advisory group of children’s orthopaedic specialists consisting of physiotherapists, surgeons, and clinical nurse specialists designed a survey. In the first round, participants also had the opportunity to suggest new statements. The survey included statements related to ‘Exercises’, ‘Physical activity’, ‘Education/information sharing’, ‘Input from other services’, and ‘Monitoring assessments’. The survey was shared with clinicians who regularly treat children with Perthes’ disease in the UK using clinically relevant specialist groups and social media. A predetermined threshold of ≥ 75% for consensus was used for recommendation, with a threshold of between 70% and 75% being considered as ‘points to consider’. Results. A total of 40 participants took part in the first round, of whom 31 completed the second round. A total of 87 statements were generated by the advisory group and included in the first round, at the end of which 31 achieved consensus and were removed from the survey, and an additional four statements were generated. A total of 60 statements were included in the second round and 45 achieved the threshold for consensus from both rounds, with three achieving the threshold for ‘points to consider’. The recommendations predominantly included self-management, particularly relating to advice about exercise and education for children with Perthes’ disease and their families. Conclusion. Children’s orthopaedic specialists have reached consensus on recommendations for non-surgical treatment in Perthes’ disease. These statements will support decisions made in clinical practice and act as a foundation to support clinicians in the absence of robust evidence. The dissemination of these findings and the best way of delivering this care needs careful consideration, which we will continue to explore. Cite this article: Bone Joint J 2024;106-B(5):501–507

Aims. Histology is an established tool in diagnosing periprosthetic joint infections (PJIs). Different thresholds, using various infection definitions and histopathological criteria, have been described. This study determined the performance of different thresholds of polymorphonuclear neutrophils (≥ 5 PMN/HPF, ≥ 10 PMN/HPF, ≥ 23 PMN/10 HPF) , when using the European Bone and Joint Infection Society (EBJIS), Infectious Diseases Society of America (IDSA), and the International Consensus Meeting (ICM) 2018 criteria for PJI. Methods. A total of 119 patients undergoing revision total hip (rTHA) or knee arthroplasty (rTKA) were included. Permanent histology sections of periprosthetic tissue were evaluated under high power (400× magnification) and neutrophils were counted per HPF. The mean neutrophil count in ten HPFs was calculated (PMN/HPF). Based on receiver operating characteristic (ROC) curve analysis and the z-test, thresholds were compared. Results. Using the EBJIS criteria, a cut-off of ≥ five PMN/HPF showed a sensitivity of 93% (95% confidence interval (CI) 81 to 98) and specificity of 84% (95% CI 74 to 91). The optimal threshold when applying the IDSA and ICM criteria was ≥ ten PMN/HPF with sensitivities of 94% (95% CI 79 to 99) and 90% (95% CI 76 to 97), and specificities of 86% (95% CI 77 to 92) and 92% (95% CI 84 to 97), respectively. In rTKA, a better performance of histopathological analysis was observed in comparison with rTHA when using the IDSA criteria (p < 0.001). Conclusion. With high accuracy, histopathological analysis can be supported as a confirmatory criterion in diagnosing periprosthetic joint infections. A threshold of ≥ five PMN/HPF can be recommended to distinguish between septic and aseptic loosening, with an increased possibility of detecting more infections caused by low-virulence organisms. However, neutrophil counts between one and five should be considered suggestive of infection and interpreted carefully in conjunction with other diagnostic test methods. Cite this article: Bone Joint Res 2021;10(8):536–547

Aims. The involvement of cyclin D1 in the proliferation of microglia, and the generation and maintenance of bone cancer pain (BCP), have not yet been clarified. We investigated the expression of microglia and cyclin D1, and the influences of cyclin D1 on pain threshold. Methods. Female Sprague Dawley (SD) rats were used to establish a rat model of BCP, and the messenger RNA (mRNA) and protein expression of ionized calcium binding adaptor molecule 1 (IBA1) and cyclin D1 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and western blot, respectively. The proliferation of spinal microglia was detected by immunohistochemistry. The pain behaviour test was assessed by quantification of spontaneous flinches, limb use, and guarding during forced ambulation, mechanical paw withdrawal threshold, and thermal paw withdrawal latency. Results. IBA1 and cyclin D1 in the ipsilateral spinal horn increased in a time-dependent fashion. Spinal microglia proliferated in BCP rats. The microglia inhibitor minocycline attenuated the pain behaviour in BCP rats. The cyclin-dependent kinase inhibitor flavopiridol inhibited the proliferation of spinal microglia, and was associated with an improvement in pain behaviour in BCP rats. Conclusion. Our results revealed that the inhibition of spinal microglial proliferation was associated with a decrease in pain behaviour in a rat model of BCP. Cyclin D1 acts as a key regulator of the proliferation of spinal microglia in a rat model of BCP. Disruption of cyclin D1, the restriction-point control of cell cycle, inhibited the proliferation of microglia and attenuated the pain behaviours in BCP rats. Cyclin D1 and the proliferation of spinal microglia may be potential targets for the clinical treatment of BCP. Cite this article: Bone Joint Res 2022;11(11):803–813

Aims. To investigate the optimal thresholds and diagnostic efficacy of commonly used serological and synovial fluid detection indexes for diagnosing periprosthetic joint infection (PJI) in patients who have rheumatoid arthritis (RA). Methods. The data from 348 patients who had RA or osteoarthritis (OA) and had previously undergone a total knee (TKA) and/or a total hip arthroplasty (THA) (including RA-PJI: 60 cases, RA-non-PJI: 80 cases; OA-PJI: 104 cases, OA-non-PJI: 104 cases) were retrospectively analyzed. A receiver operating characteristic curve was used to determine the optimal thresholds of the CRP, ESR, synovial fluid white blood cell count (WBC), and polymorphonuclear neutrophil percentage (PMN%) for diagnosing RA-PJI and OA-PJI. The diagnostic efficacy was evaluated by comparing the area under the curve (AUC) of each index and applying the results of the combined index diagnostic test. Results. For PJI prediction, the results of serological and synovial fluid indexes were different between the RA-PJI and OA-PJI groups. The optimal cutoff value of CRP for diagnosing RA-PJI was 12.5 mg/l, ESR was 39 mm/hour, synovial fluid WBC was 3,654/μl, and PMN% was 65.9%; and those of OA-PJI were 8.2 mg/l, 31 mm/hour, 2,673/μl, and 62.0%, respectively. In the RA-PJI group, the specificity (94.4%), positive predictive value (97.1%), and AUC (0.916) of synovial fluid WBC were higher than those of the other indexes. The optimal cutoff values of synovial fluid WBC and PMN% for diagnosing RA-PJI after THA were significantly higher than those of TKA. The specificity and positive predictive value of the combined index were 100%. Conclusion. Serum inflammatory and synovial fluid indexes can be used for diagnosing RA-PJI, for which synovial fluid WBC is the best detection index. Combining multiple detection indexes can provide a reference basis for the early and accurate diagnosis of RA-PJI. Cite this article: Bone Joint Res 2023;12(9):559–570

Aims. Instability is a common cause of failure after total hip arthroplasty. A novel reverse total hip has been developed, with a femoral cup and acetabular ball, creating enhanced mechanical stability. The purpose of this study was to assess the implant fixation using radiostereometric analysis (RSA), and the clinical safety and efficacy of this novel design. Methods. Patients with end-stage osteoarthritis were enrolled in a prospective cohort at a single centre. The cohort consisted of 11 females and 11 males with mean age of 70.6 years (SD 3.5) and BMI of 31.0 kg/m. 2. (SD 5.7). Implant fixation was evaluated using RSA as well as Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score, Oxford Hip Score, Hip disability and Osteoarthritis Outcome Score, 38-item Short Form survey, and EuroQol five-dimension health questionnaire scores at two-year follow-up. At least one acetabular screw was used in all cases. RSA markers were inserted into the innominate bone and proximal femur with imaging at six weeks (baseline) and six, 12, and 24 months. Independent-samples t-tests were used to compare to published thresholds. Results. Mean acetabular subsidence from baseline to 24 months was 0.087 mm (SD 0.152), below the critical threshold of 0.2 mm (p = 0.005). Mean femoral subsidence from baseline to 24 months was -0.002 mm (SD 0.194), below the published reference of 0.5 mm (p < 0.001). There was significant improvement in patient-reported outcome measures at 24 months with good to excellent results. Conclusion. RSA analysis demonstrates excellent fixation with a predicted low risk of revision at ten years of this novel reverse total hip system. Clinical outcomes were consistent with safe and effective hip replacement prostheses. Cite this article: Bone Jt Open 2023;4(5):385–392

Aims. To evaluate inducing osteoarthritis (OA) by surgical destabilization of the medial meniscus (DMM) in mice with and without a stereomicroscope. Methods. Based on sample size calculation, 70 male C57BL/6 mice were randomly assigned to three surgery groups: DMM aided by a stereomicroscope; DMM by naked eye; or sham surgery. The group information was blinded to researchers. Mice underwent static weightbearing, von Frey test, and gait analysis at two-week intervals from eight to 16 weeks after surgery. Histological grade of OA was determined with the Osteoarthritis Research Society International (OARSI) scoring system. Results. Surgical DMM with or without stereomicroscope led to decrease in the mean of weightbearing percentages (-20.64% vs -21.44%, p = 0.792) and paw withdrawal response thresholds (-21.35% vs -24.65%, p = 0.327) of the hind limbs. However, the coefficient of variation (CV) of weight-bearing percentages and paw withdrawal response thresholds in naked-eye group were significantly greater than that in the microscope group (19.82% vs 6.94%, p < 0.001; 21.85% vs 9.86%, p < 0.001). The gait analysis showed a similar pattern. Cartilage degeneration was observed in both DMM-surgery groups, evidenced by increased OARSI scores (summed score: 11.23 vs 11.43, p = 0.842), but the microscope group showed less variation in OARSI score than the naked-eye group (CV: 21.03% vs 32.44%; p = 0.032). Conclusion. Although surgical DMM aided by stereomicroscope is technically difficult, it produces a relatively more homogeneous OA model in terms of the discrete degree of pain behaviours and histopathological grading when compared with surgical DMM without stereomicroscope. Cite this article: Bone Joint Res 2022;11(8):518–527

Aims. To compare the cost-utility of removable brace compared with cast in the management of adult patients with ankle fracture. Methods. A within-trial economic evaluation conducted from the UK NHS and personnel social services (PSS) perspective. Health resources and quality-of-life data were collected as part of the Ankle Injury Rehabilitation (AIR) multicentre, randomized controlled trial over a 12-month period using trial case report forms and patient-completed questionnaires. Cost-utility analysis was estimated in terms of the incremental cost per quality adjusted life year (QALY) gained. Estimate uncertainty was explored by bootstrapping, visualized on the incremental cost-effectiveness ratio plane. Net monetary benefit and probability of cost-effectiveness were evaluated at a range of willingness-to-pay thresholds and visualized graphically. Results. The incremental cost and QALYs of using brace over a 12-month period were £46.73 (95% confidence interval (CI) £-9 to £147) and 0.0141 (95% CI -0.005 to 0.033), respectively. The cost per QALY gained was £3,318. The probability of brace being cost-effective at a £30,000 per QALY willingness-to-pay threshold was 88%. The results remained robust to a range of sensitivity analyses. Conclusion. This within-trial economic evaluation found that it is probable that using a removable brace provides good value to the NHS when compared to cast, in the management of adults with ankle fracture. Cite this article: Bone Jt Open 2022;3(6):455–462

Aims. Proximal femur fractures treatment can involve anterograde nailing with a single or double cephalic screw. An undesirable failure for this fixation is screw cut-out. In a single-screw nail, a tip-apex distance (TAD) greater than 25 mm has been associated with an increased risk of cut-out. The aim of the study was to examine the role of TAD as a risk factor in a cephalic double-screw nail. Methods. A retrospective study was conducted on 112 patients treated for intertrochanteric femur fracture with a double proximal screw nail (Endovis BA2; EBA2) from January to September 2021. The analyzed variables were age, sex, BMI, comorbidities, fracture type, side, time of surgery, quality of reduction, pre-existing therapy with bisphosphonate for osteoporosis, screw placement in two different views, and TAD. The last follow-up was at 12 months. Logistic regression was used to study the potential factors of screw cut-out, and receiver operating characteristic curve to identify the threshold value. Results. A total of 98 of the 112 patients met the inclusion criteria. Overall, 65 patients were female (66.3%), the mean age was 83.23 years (SD 7.07), and the mean follow-up was 378 days (SD 36). Cut-out was observed in five patients (5.10%). The variables identified by univariate analysis with p < 0.05 were included in the multivariate logistic regression model were screw placement and TAD. The TAD was significant with an odds ratio (OR) 5.03 (p = 0.012) as the screw placement with an OR 4.35 (p = 0.043) in the anteroposterior view, and OR 10.61 (p = 0.037) in the lateral view. The TAD threshold value identified was 29.50 mm. Conclusion. Our study confirmed the risk factors for cut-out in the double-screw nail are comparable to those in the single screw. We found a TAD value of 29.50 mm to be associated with a risk of cut-out in double-screw nails, when good fracture reduction is granted. This value is higher than the one reported with single-screw nails. Therefore, we suggest the role of TAD should be reconsidered in well-reduced fractures treated with double-screw intramedullary nail. Cite this article: Bone Jt Open 2024;5(6):457–463

Aims. Prior cost-effectiveness analyses on osseointegrated prosthesis for transfemoral unilateral amputees have analyzed outcomes in non-USA countries using generic quality of life instruments, which may not be appropriate when evaluating disease-specific quality of life. These prior analyses have also focused only on patients who had failed a socket-based prosthesis. The aim of the current study is to use a disease-specific quality of life instrument, which can more accurately reflect a patient’s quality of life with this condition in order to evaluate cost-effectiveness, examining both treatment-naïve and socket refractory patients. Methods. Lifetime Markov models were developed evaluating active healthy middle-aged male amputees. Costs of the prostheses, associated complications, use/non-use, and annual costs of arthroplasty parts and service for both a socket and osseointegrated (OPRA) prosthesis were included. Effectiveness was evaluated using the questionnaire for persons with a transfemoral amputation (Q-TFA) until death. All costs and Q-TFA were discounted at 3% annually. Sensitivity analyses on those cost variables which affected a change in treatment (OPRA to socket, or socket to OPRA) were evaluated to determine threshold values. Incremental cost-effectiveness ratios (ICERs) were calculated. Results. For treatment-naïve patients, the lifetime ICER for OPRA was $279/quality-adjusted life-year (QALY). For treatment-refractory patients the ICER was $273/QALY. In sensitivity analysis, the variable thresholds that would affect a change in the course of treatment based on cost (from socket to OPRA), included the following for the treatment-naïve group: yearly replacement components for socket > $8,511; cost yearly replacement parts OPRA < $1,758; and for treatment-refractory group: yearly replacement component for socket of > $12,467. Conclusion. The use of the OPRA prosthesis in physically active transfemoral amputees should be considered as a cost-effective alternative in both treatment-naïve and treatment-refractory socket prosthesis patients. Disease-specific quality of life assessments such as Q-TFA are more sensitive when evaluating cost-effectiveness. Cite this article: Bone Jt Open 2024;5(3):218–226

Aims. The Forgotten Joint Score-12 (FJS-12) is a validated patient-reported outcome measure (PROM) tool designed to assess artificial prosthesis awareness during daily activities following total hip arthroplasty (THA). The patient-acceptable symptom state (PASS) is the minimum cut-off value that corresponds to a patient’s satisfactory state-of-health. Despite the validity and reliability of the FJS-12 having been previously demonstrated, the PASS has yet to be clearly defined. This study aims to define the PASS of the FJS-12 following primary THA. Methods. We retrospectively reviewed all patients who underwent primary elective THA from 2019 to 2020, and answered both the FJS-12 and the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) questionnaires one-year postoperatively. HOOS, JR score was used as the anchor to estimate the PASS of FJS-12. Two statistical methods were employed: the receiver operating characteristic (ROC) curve point, which maximized the Youden index; and 75th percentile of the cumulative percentage curve of patients who had the HOOS, JR score difference larger than the cut-off value. Results. This study included 780 patients. The mean one-year FJS-12 score was 65.42 (SD 28.59). The mean one-year HOOS, JR score was 82.70 (SD 16.57). A high positive correlation between FJS-12 and HOOS, JR was found (r = 0.74; p<0.001), making the HOOS, JR a valid external anchor. The threshold score of the FJS-12 that maximized the sensitivity and specificity for detecting a PASS was 66.68 (area under the curve = 0.8). The cut-off score value computed with the 75th percentile approach was 92.20. Conclusion. The PASS threshold for the FJS-12 at one year following primary THA was 66.68 and 92.20 using the ROC curve and 75th percentile approaches, respectively. These values can be used to achieve consensus about meaningful postoperative improvement to maximize the utility of the FJS-12 to evaluate and counsel patients undergoing THA. Cite this article: Bone Jt Open 2022;3(4):307–313

Aims. This systematic review aims to identify 3D predictors derived from biplanar reconstruction, and to describe current methods for improving curve prediction in patients with mild adolescent idiopathic scoliosis. Methods. A comprehensive search was conducted by three independent investigators on MEDLINE, PubMed, Web of Science, and Cochrane Library. Search terms included “adolescent idiopathic scoliosis”,“3D”, and “progression”. The inclusion and exclusion criteria were carefully defined to include clinical studies. Risk of bias was assessed with the Quality in Prognostic Studies tool (QUIPS) and Appraisal tool for Cross-Sectional Studies (AXIS), and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. In all, 915 publications were identified, with 377 articles subjected to full-text screening; overall, 31 articles were included. Results. Torsion index (TI) and apical vertebral rotation (AVR) were identified as accurate predictors of curve progression in early visits. Initial TI > 3.7° and AVR > 5.8° were predictive of curve progression. Thoracic hypokyphosis was inconsistently observed in progressive curves with weak evidence. While sagittal wedging was observed in mild curves, there is insufficient evidence for its correlation with curve progression. In curves with initial Cobb angle < 25°, Cobb angle was a poor predictor for future curve progression. Prediction accuracy was improved by incorporating serial reconstructions in stepwise layers. However, a lack of post-hoc analysis was identified in studies involving geometrical models. Conclusion. For patients with mild curves, TI and AVR were identified as predictors of curve progression, with TI > 3.7° and AVR > 5.8° found to be important thresholds. Cobb angle acts as a poor predictor in mild curves, and more investigations are required to assess thoracic kyphosis and wedging as predictors. Cumulative reconstruction of radiographs improves prediction accuracy. Comprehensive analysis between progressive and non-progressive curves is recommended to extract meaningful thresholds for clinical prognostication. Cite this article: Bone Jt Open 2024;5(3):243–251

Aims. The aim of this study was to estimate the incremental use of resources, costs, and quality of life outcomes associated with surgical reconstruction compared to rehabilitation for long-standing anterior cruciate ligament (ACL) injury in the NHS, and to estimate its cost-effectiveness. Methods. A total of 316 patients were recruited and randomly assigned to either surgical reconstruction or rehabilitation (physiotherapy but with subsequent reconstruction permitted if instability persisted after treatment). Healthcare resource use and health-related quality of life data (EuroQol five-dimension five-level health questionnaire) were collected in the trial at six, 12, and 18 months using self-reported questionnaires and medical records. Using intention-to-treat analysis, differences in costs, and quality-adjusted life years (QALYs) between treatment arms were estimated adjusting for baseline differences and following multiple imputation of missing data. The incremental cost-effectiveness ratio (ICER) was estimated as the difference in costs divided by the difference in QALYs between reconstruction and rehabilitation. Results. At 18 months, patients in the surgical reconstruction arm reported higher QALYs (0.052 (95% confidence interval (CI) -0.012 to 0.117); p = 0.177) and higher NHS costs (£1,017 (95% CI 557 to 1,476); p < 0.001) compared to rehabilitation. This resulted in an ICER of £19,346 per QALY with the probability of surgical reconstruction being cost-effective of 51% and 72% at a willingness-to-pay threshold of £20,000 and £30,000 per QALY, respectively. Conclusion. Surgical reconstruction as a management strategy for patients with long-standing ACL injury is more effective, but more expensive, at 18 months compared to rehabilitation management. In the UK setting, surgical reconstruction is cost-effective. Cite this article: Bone Joint J 2024;106-B(1):38–45

Aims. The aim of this trial was to assess the cost-effectiveness of a soft bandage and immediate discharge, compared with rigid immobilization, in children aged four to 15 years with a torus fracture of the distal radius. Methods. A within-trial economic evaluation was conducted from the UK NHS and personal social services (PSS) perspective, as well as a broader societal point of view. Health resources and quality of life (the youth version of the EuroQol five-dimension questionnaire (EQ-5D-Y)) data were collected, as part of the Forearm Recovery in Children Evaluation (FORCE) multicentre randomized controlled trial over a six-week period, using trial case report forms and patient-completed questionnaires. Costs and health gains (quality-adjusted life years (QALYs)) were estimated for the two trial treatment groups. Regression was used to estimate the probability of the new treatment being cost-effective at a range of ‘willingness-to-pay’ thresholds, which reflect a range of costs per QALY at which governments are typically prepared to reimburse for treatment. Results. The offer of a soft bandage significantly reduced cost per patient (saving £12.55 (95% confidence interval (CI) -£5.30 to £19.80)) while QALYs were similar (QALY difference between groups: 0.0013 (95% CI -0.0004 to 0.003)). The high probability (95%) that offering a bandage is a cost-effective option was consistent when examining the data in a range of sensitivity analyses. Conclusion. In addition to the known clinical equivalence, this study found that the offer of a bandage reduced cost compared with rigid immobilization among children with a torus fracture of the distal radius. While the cost saving was small for each patient, the high frequency of these injuries indicates a significant saving across the healthcare system. Cite this article: Bone Joint J 2024;106-B(6):623–630

Aims. Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion. Methods. All patients who underwent elective THA were analyzed retrospectively in this single-centre study from 2020 to 2021. A total of 2,892 patients were included. Transfusion-related parameters were evaluated. A multiple logistic regression was performed to determine whether age, BMI, American Society of Anesthesiologists (ASA) grade, sex, or preoperative haemoglobin (Hb) could predict the need for transfusion within the examined patient population. Results. The overall transfusion rate was 1.2%. Compared to the group of patients without blood transfusion, the transfused group was on average older (aged 73.8 years (SD 9.7) vs 68.6 years (SD 10.1); p = 0.020) and was mostly female (p = 0.003), but showed no significant differences in terms of BMI (28.3 kg/m. 2. (SD 5.9) vs 28.7 kg/m. 2. (SD 5.2); p = 0.720) or ASA grade (2.2 (SD 0.5) vs 2.1 (SD 0.4); p = 0.378). The regression model identified a cutoff Hb level of < 7.6 mmol/l (< 12.2 g/dl), aged > 73 years, and a BMI of 35.4 kg/m² or higher as the three most reliable predictors associated with postoperative transfusion in THA. Conclusion. The possibility of transfusion is predictable based on preoperatively available parameters. The proposed thresholds for preoperative Hb level, age, and BMI can help identify patients and take preventive measures if necessary. Cite this article: Bone Jt Open 2024;5(7):560–564

Aims. A novel enhanced cement fixation (EF) tibial implant with deeper cement pockets and a more roughened bonding surface was released to market for an existing total knee arthroplasty (TKA) system.This randomized controlled trial assessed fixation of the both the EF (ATTUNE S+) and standard (Std; ATTUNE S) using radiostereometric analysis. Methods. Overall, 50 subjects were randomized (21 EF-TKA and 23 Std-TKA in the final analysis), and had follow-up visits at six weeks, and six, 12, and 24 months to assess migration of the tibial component. Low viscosity bone cement with tobramycin was used in a standardized fashion for all subjects. Patient-reported outcome measure data was captured at preoperative and all postoperative visits. Results. The patient cohort mean age was 66 years (SD seven years), 59% were female, and the mean BMI was 32 kg/m. 2. (SD 6 kg/m. 2. ). Mean two-year subsidence of the EF-TKA was 0.056 mm (95% confidence interval (CI) 0.025 to 0.086) versus 0.006 mm (95% CI -0.029 to 0.040) for the Std-TKA, and the two-year maximum total point motion (MTPM) was 0.285 mm (95% upper confidence limit (UCL) ≤ 0.363) versus 0.346 mm (95% UCL ≤ 0.432), respectively, for a mean difference of -0.061 mm (95% CI -0.196 to 0.074). Inducible displacement also did not differ between groups. The MTPMs between 12 and 24 months for each group was below the published threshold of 0.2 mm for predicting early aseptic loosening (p < 0.001 and p = 0.001, respectively). Conclusion. Both the enhanced fixation and the standard tibial implant design showed fixation with a predicted low risk of long-term aseptic loosening. Cite this article: Bone Jt Open 2024;5(1):20–27