Aims. To establish the survivorship, function, and metal ion levels in an unselected series of metal-on-metal hip resurfacing arthroplasties (HRAs) performed by a non-designer surgeon. Methods. We reviewed 105 consecutive HRAs in 83 patients, performed by a single surgeon, at a mean follow-up of 14.9 years (9.3 to 19.1). The cohort included 45 male and 38 female patients, with a mean age of 49.5 years (SD 12.5). Results. At the time of review 13 patients with 15 hips had died from causes unrelated to the hip operation, and 14 hips had undergone revision surgery, giving an overall survival rate of rate of 86.7% (95% confidence interval (CI) 84.2 to 89.1). The survival rate in men was 97.7% (95% CI 96.3 to 98.9) and in women was 73.4% (95% CI 70.6 to 75.1). The median head size of the failed group was 42 mm (interquartile range (IQR) 42 to 44), and in the surviving group was 50 mm (IQR 46 to 50). In all, 13 of the 14 revised hips had a femoral component measuring ≤ 46 mm. The mean blood levels of cobalt and chromium ions were 26.6 nmol/l (SD 24.5) and 30.6 nmol/l (SD 15.3), respectively. No metal ion levels exceeded the safe limit. The mean Oxford Hip Score was 41.5 (SD 8.9) and Harris Hip Score was 89.9 (14.8). In the surviving group, four patients had radiolucent lines around the stem of the femoral component, and one had lysis around the acetabular component; eight hips demonstrated heterotopic ossification. Conclusion. Our results confirm the existing understanding that HRA provides good long-term survival and function in patients with adequate-sized femoral heads. This is evidenced by a 97.7% survival rate among men (larger heads) in our series at a mean follow-up of 14.9 years. Failure is closely related to head sizes ≤ 46 cm. Cite this article: Bone Jt Open 2022;3(1):68–76

Aims. The aim of this study was to identify the origin and development of the threshold for surgical intervention, highlight the consequences of residual displacement, and justify the importance of accurate measurement. Methods. A systematic review of three databases was performed to establish the origin and adaptations of the threshold, with papers screened and relevant citations reviewed. This search identified papers investigating functional outcome, including presence of arthritis, following injury. Orthopaedic textbooks were reviewed to ensure no earlier mention of the threshold was present. Results. Knirk and Jupiter (1986) were the first to quantify a threshold, with all their patients developing arthritis with > 2 mm displacement. Some papers have discussed using 1 mm, although 2 mm is most widely reported. Current guidance from the British Society for Surgery of the Hand and a Delphi panel support 2 mm as an appropriate value. Although this paper is still widely cited, the authors published a re-examination of the data showing methodological flaws which is not as widely reported. They claim their conclusions are still relevant today; however, radiological arthritis does not correlate with the clinical presentation. Function following injury has been shown to be equivalent to an uninjured population, with arthritis progressing slowly or not at all. Joint space narrowing has also been shown to often be benign. Conclusion. Knirk and Jupiter originated the threshold value of 2 mm. The lack of correlation between the radiological and clinical presentations warrants further modern investigation. Measurement often varies between observers, calling a threshold concept into question and showing the need for further development in this area. The principle of treatment remains restoration of normal anatomical position. Cite this article: Bone Joint J 2021;103-B(9):1457–1461

Aims. The aim of this study was to conduct a cross-sectional, observational cohort study of patients presenting for revision of a total hip, or total or unicompartmental knee arthroplasty, to understand current routes to revision surgery and explore differences in symptoms, healthcare use, reason for revision, and the revision surgery (surgical time, components, length of stay) between patients having regular follow-up and those without. Methods. Data were collected from participants and medical records for the 12 months prior to revision. Patients with previous revision, metal-on-metal articulations, or hip hemiarthroplasty were excluded. Participants were retrospectively classified as ‘Planned’ or ‘Unplanned’ revision. Multilevel regression and propensity score matching were used to compare the two groups. Results. Data were analyzed from 568 patients, recruited in 38 UK secondary care sites between October 2017 and October 2018 (43.5% male; mean (SD) age 71.86 years (9.93); 305 hips, 263 knees). No significant inclusion differences were identified between the two groups. For hip revision, time to revision > ten years (odds ratio (OR) 3.804, 95% confidence interval (CI) (1.353 to 10.694), p = 0.011), periprosthetic fracture (OR 20.309, 95% CI (4.574 to 90.179), p < 0.001), and dislocation (OR 12.953, 95% CI (4.014 to 41.794), p < 0.001), were associated with unplanned revision. For knee, there were no associations with route to revision. Revision after ten years was more likely for those who were younger at primary surgery, regardless of route to revision. No significant differences in cost outcomes, length of surgery time, and access to a health professional in the year prior to revision were found between the two groups. When periprosthetic fractures, dislocations, and infections were excluded, healthcare use was significantly higher in the unplanned revision group. Conclusion. Differences between characteristics for patients presenting for planned and unplanned revision are minimal. Although there was greater healthcare use in those having unplanned revision, it appears unlikely that routine orthopaedic review would have detected many of these issues. It may be safe to disinvest in standard follow-up provided there is rapid access to orthopaedic review. Cite this article: Bone Joint J 2022;104-B(1):59–67

Aims. Although the short stem concept in hip arthroplasty procedure shows acceptable clinical performance, we sometimes get unexplainable radiological findings. The aim of this retrospective study was to evaluate changes of radiological findings up to three years postoperatively, and to assess any potential contributing factors on such radiological change in a Japanese population. Methods. This is a retrospective radiological study conducted in Japan. Radiological assessment was done in accordance with predetermined radiological review protocol. A total of 241 hips were included in the study and 118 hips (49.0%) revealed radiological change from immediately after surgery to one year postoperatively; these 118 hips were eligible for further analyses. Each investigator screened whether either radiolucent lines (RLLs), cortical hypertrophy (CH), or atrophy (AT) appeared or not on the one-year radiograph. Further, three-year radiographs of eligible cases were reviewed to determine changes such as, disappeared (D), improved (I), stable (S), and progression (P). Additionally, bone condensation (BC) was assessed on the three-year radiograph. Results. CH was observed in 49 hips (21.1%), AT was observed in 63 hips (27.2%), and RLLs were observed in 34 hips (14.7%) at one year postoperatively. Among 34 hips with RLLs, 70.6% showed change of either D or I on the three-year radiograph. BC was observed in younger patients more frequently. Conclusion. The Fitmore stem works well in a Japanese population with favourable radiological change on hips with RLLs. Longer-term follow-up is required to determine clinical relevance. Cite this article: Bone Jt Open 2022;3(1):20–28

Aims. The aim of this study is to develop a core set of outcome domains that should be considered and reported in all future trials of childhood limb fractures. Methods. A four-phase study was conducted to agree a set of core outcome domains. Identification of candidate outcome domains were identified through systematic review of trials, and outcome domains relevant to families were identified through semi-structured interviews with 20 families (parent-child pairing or group). Outcome domains were prioritized using an international three-round Delphi survey with 205 panellists and then condensed into a core outcome set through a consensus workshop with 30 stakeholders. Results. The systematic review and interviews identified 85 outcome domains as relevant to professionals or families. The Delphi survey prioritized 30 upper and 29 lower limb outcome domains at first round, an additional 17 upper and 18 lower limb outcomes at second round, and four additional outcomes for upper and lower limb at the third round as important domains. At the consensus workshop, the core outcome domains were agreed as: 1) pain and discomfort; 2) return to physical and recreational activities; 3) emotional and psychosocial wellbeing; 4) complications from the injury and treatment; 5) rturn to baseline activities daily living; 6) participation in learning; 7) appearance and deformity; and 8) time to union. In addition, 9a) recovery of mobility and 9b) recovery of manual dexterity was recommended as a core outcome for lower and upper limb fractures, respectively. Conclusion. This set of core outcome domains is recommended as a minimum set of outcomes to be reported in all trials. It is not an exhaustive set and further work is required to identify what outcome tools should be used to measure each of these outcomes. Adoption of this outcome set will improve the consistency of research for these children that can be combined for more meaningful meta-analyses and policy development. Cite this article: Bone Joint J 2021;103-B(12):1821–1830

Aims. This systematic review places a recently completed multicentre randomized controlled trial (RCT), UK FROST, in the context of existing randomized evidence for the management of primary frozen shoulder. UK FROST compared the effectiveness of pre-specified physiotherapy techniques with a steroid injection (PTSI), manipulation under anaesthesia (MUA) with a steroid injection, and arthroscopic capsular release (ACR). This review updates a 2012 review focusing on the effectiveness of MUA, ACR, hydrodilatation, and PTSI. Methods. MEDLINE, Embase, PEDro, Science Citation Index, Clinicaltrials.gov, CENTRAL, and the World Health Organization (WHO) International Clinical Trials Registry were searched up to December 2018. Reference lists of included studies were screened. No language restrictions applied. Eligible studies were RCTs comparing the effectiveness of MUA, ACR, PTSI, and hydrodilatation against each other, or supportive care or no treatment, for the management of primary frozen shoulder. Results. Nine RCTs were included. The primary outcome of patient-reported shoulder function at long-term follow-up (> 6 months and ≤ 12 months) was reported for five treatment comparisons across four studies. Standardized mean differences (SMD) were: ACR versus MUA: 0.21 (95% confidence interval (CI) 0.00 to 0.42), ACR versus supportive care: -0.13 (95% CI -1.10 to 0.83), and ACR versus PTSI: 0.33 (95% CI 0.07 to 0.59) and 0.25 (95% CI -0.34 to 0.85), all favouring ACR; MUA versus supportive care: 0 (95% CI -0.44 to 0.44) not favouring either; and MUA versus PTSI: 0.12 (95% CI -0.14 to 0.37) favouring MUA. None of these differences met the threshold of clinical significance agreed for the UK FROST and most confidence intervals included zero. Conclusion. The findings from a recent multicentre RCT provided the strongest evidence that, when compared with each other, neither PTSI, MUA, nor ACR are clinically superior. Evidence from smaller RCTs did not change this conclusion. The effectiveness of hydrodilatation based on four RCTs was inconclusive and there remains an evidence gap. Cite this article: Bone Jt Open 2021;2(9):773–784

Aims. The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR. Methods. We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks). Results. Meniscal repair survivorship at a median final follow-up of 55 months (interquartile range (IQR) 24 to 91) was 82% (95% confidence interval 70 to 89). A total of 13 meniscus repairs failed (12 requiring meniscectomy and one requiring a further meniscal repair). At final follow-up, median PROMs were: EQ-VAS 85 (IQR 75 to 90), EQ-5D Index 0.84 (IQR 0.74 to 1.00), KOOS Pain 89 (IQR 80 to 94), KOOS Symptoms 82 (IQR 71 to 93), KOOS Activities of Daily Living 97 (IQR 91 to 100), KOOS Sport and Recreation 80 (IQR 65 to 90), KOOS Quality of Life 69 (IQR 53 to 86), IKDC 82.8 (IQR 67.8 to 90.8), and Tegner 6 (IQR 4 to 7). Two patients underwent revision ACLR following further injuries. One patient had an arthroscopic washout for infection at 11 days post-BH meniscal repair/ACLR. Four patients (4.5%) required a further procedure for stiffness, reduced ROM, and pain, and all were operated on within three weeks of meniscal injury. There was no difference in the interval between meniscal injury and surgery between repairs that failed and those that survived. Conclusion. These data suggest that concomitant ACLR with repair of displaced BH meniscal tears, even if they have been displaced for some time, appears to afford satisfactory PROMs and good survivorship. Repairs within three weeks of meniscal injury may be associated with higher rates of postoperative reintervention for stiffness. Cite this article: Bone Joint J 2022;104-B(6):680–686

Aims. The aim of this study was to evaluate the incidence of liner malseating in two commonly used dual-mobility (DM) designs. Secondary aims included determining the risk of dislocation, survival, and clinical outcomes. Methods. We retrospectively identified 256 primary total hip arthroplasties (THAs) that included a DM component (144 Stryker MDM and 112 Zimmer-Biomet G7) in 233 patients, performed between January 2012 and December 2019. Postoperative radiographs were reviewed independently for malseating of the liner by five reviewers. The mean age of the patients at the time of THA was 66 years (18 to 93), 166 (65%) were female, and the mean BMI was 30 kg/m. 2. (17 to 57). The mean follow-up was 3.5 years (2.0 to 9.2). Results. Three liners (1.2%) were malseated, including two MDMs (1.4%) and one G7 (0.9%). No clinical consequence was identified from malseating. The five-year survival free of dislocation was 97.1%, including two DM and one intraprosthetic dislocation. The five-year survival free of revision was 95.4%, with seven revisions. The mean Harris Hip Scores increased from 46 (24 to 69) preoperatively to 81 (40 to 100) at two years postoperatively (p < 0.001). Conclusion. The incidence of DM liner malseating after primary THA was low, with no known clinical consequences at mid-term follow-up. Malseating is not exclusive of design, and these findings emphasize the importance of careful evaluation of the liner after impaction to avoid this complication. Cite this article: Bone Joint J 2022;104-B(5):598–603

Osteoarthritis (OA) is a degenerative disease resulting from progressive joint destruction caused by many factors. Its pathogenesis is complex and has not been elucidated to date. Advanced glycation end products (AGEs) are a series of irreversible and stable macromolecular complexes formed by reducing sugar with protein, lipid, and nucleic acid through a non-enzymatic glycosylation reaction (Maillard reaction). They are an important indicator of the degree of ageing. Currently, it is considered that AGEs accumulation in vivo is a molecular basis of age-induced OA, and AGEs production and accumulation in vivo is one of the important reasons for the induction and acceleration of the pathological changes of OA. In recent years, it has been found that AGEs are involved in a variety of pathological processes of OA, including extracellular matrix degradation, chondrocyte apoptosis, and autophagy. Clearly, AGEs play an important role in regulating the expression of OA-related genes and maintaining the chondrocyte phenotype and the stability of the intra-articular environment. This article reviews the latest research results of AGEs in a variety of pathological processes of OA, to provide a new direction for the study of OA pathogenesis and a new target for prevention and treatment. Cite this article: Bone Joint Res 2022;11(5):292–300

Aims. The aim of the study was to determine if there was a direct correlation between the pain and disability experienced by patients and size of their disc prolapse, measured by the disc’s cross-sectional area on T2 axial MRI scans. Methods. Patients were asked to prospectively complete visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores on the day of their MRI scan. All patients with primary disc herniation were included. Exclusion criteria included recurrent disc herniation, cauda equina syndrome, or any other associated spinal pathology. T2 weighted MRI scans were reviewed on picture archiving and communications software. The T2 axial image showing the disc protrusion with the largest cross sectional area was used for measurements. The area of the disc and canal were measured at this level. The size of the disc was measured as a percentage of the cross-sectional area of the spinal canal on the chosen image. The VAS leg pain and ODI scores were each correlated with the size of the disc using the Pearson correlation coefficient (PCC). Intraobserver reliability for MRI measurement was assessed using the interclass correlation coefficient (ICC). We assessed if the position of the disc prolapse (central, lateral recess, or foraminal) altered the symptoms described by the patient. The VAS and ODI scores from central and lateral recess disc prolapses were compared. Results. A total of 56 patients (mean age 41.1 years (22.8 to 70.3)) were included. A high degree of intraobserver reliability was observed for MRI measurement: single measure ICC was 0.99 (95% confidence interval (CI) from 0.97 to 0.99 (p < 0.001)). The PCC comparing VAS leg scores with canal occupancy for herniated disc was 0.056. The PCC comparing ODI for herniated disc was 0.070. We found 13 disc prolapses centrally and 43 lateral recess prolapses. There were no foraminal prolapses in this group. The position of the prolapse was not found to be related to the mean VAS score or ODI experienced by the patients (VAS, p = 0.251; ODI, p = 0.093). Conclusion. The results of the statistical analysis show that there is no direct correlation between the size or position of the disc prolapse and a patient’s symptoms. The symptoms experienced by patients should be the primary concern in deciding to perform discectomy. Cite this article: Bone Joint J 2022;104-B(6):715–720

Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability. Cite this article: Bone Jt Open 2022;3(3):268–274

Aims. This systematic review and meta-analysis was conducted to compare open reduction and internal fixation (ORIF) with primary arthrodesis (PA) in the treatment of Lisfranc injuries, regarding patient-reported outcome measures (PROMs), and risk of secondary surgery. The aim was to conclusively determine the best available treatment based on the most complete and recent evidence available. Methods. A systematic search was conducted in PubMed, Cochrane Controlled Register of Trials (CENTRAL), EMBASE, CINAHL, PEDro, and SPORTDiscus. Additionally, ongoing trial registers and reference lists of included articles were screened. Risk of bias (RoB) and level of evidence were assessed using the Cochrane risk of bias tools and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool. The random and fixed-effect models were used for the statistical analysis. Results. A total of 20 studies were selected for this review, of which 12 were comparative studies fit for meta-analysis, including three randomized controlled trials (RCTs). This resulted in a total analyzed population of 392 patients treated with ORIF and 249 patients treated with PA. The mean differences between the two groups in American Orthopedic Foot and Ankle Society (AOFAS), VAS, and SF-36 scores were -7.41 (95% confidence interval (CI) -13.31 to -1.51), 0.77 (95% CI -0.85 to 2.39), and -1.20 (95% CI -3.86 to 1.46), respectively. Conclusion. This is the first study to find a statistically significant difference in PROMs, as measured by the AOFAS score, in favour of PA for the treatment of Lisfranc injuries. However, this difference may not be clinically relevant, and therefore drawing a definitive conclusion requires confirmation by a large prospective high-quality RCT. Such a study should also assess cost-effectiveness, as cost considerations might be decisive in decision-making. Level of Evidence: I. Cite this article: Bone Jt Open 2021;2(10):842–849

Aims. Hydroxyapatite (HA)-coated collars have been shown to reduce aseptic loosening of massive endoprostheses following primary surgery. Limited information exists about their effectiveness in revision surgery. The aim of this study was to radiologically assess osteointegration to HA-coated collars of cemented massive endoprostheses following revision surgery. Methods. Retrospective review of osseointegration frequency, pattern, and timing to a specific HA-coated collar on massive endoprostheses used in revision surgery at our tertiary referral centre between 2010 to 2017 was undertaken. Osseointegration was radiologically classified on cases with a minimum follow-up of six months. Results. In all, 39 patients underwent radiological review at mean 43.5 months; 22/39 (56.4%) showed no osseointegration to the collar. Revision endoprostheses for aseptic loosening were less likely to show osseointegration compared with other indications for revision. Oncological cases with previous or current infection were more likely to show osseointegration to ≥ 1 collar side than those without evidence of prior infection. Conclusion. This seven-year review identified osseointegration of HA-coated collars after revision surgery is less likely (43.6%, 17/39) than after primary surgery. Young patients who undergo revision surgery following initial oncological indication may benefit the most from this collar design. Use in revision oncological cases with a history of infection may be beneficial. HA-coated collars showed limited benefit for patients undergoing revision for failed arthroplasty with history of infection. Cite this article: Bone Jt Open 2021;2(6):371–379

Aims. Debridement, antibiotics, and implant retention (DAIR) is a widely accepted form of surgical treatment for patients with an early periprosthetic joint infection (PJI) after primary arthroplasty. The outcome of DAIR after revision arthroplasty, however, has not been reported. The aim of this study was to report the success rate of DAIR after revision arthroplasty with a follow-up of two years. Methods. This retrospective study, conducted at the Sint Maartenskliniek, Nijmegen, the Netherlands, included 88 patients who underwent DAIR within 90 days of revision total hip or total knee arthroplasty between 2012 and 2019. Details of the surgical procedures and PJI were collected. Univariate analysis and a subgroup analysis of the culture-positive group were performed. Kaplan-Meier survivorship curves were constructed. Results. The overall success rate of DAIR, with respect to the retention of components and the cure of infection, was 68% after two years. DAIR performed with an interval of > 30 days after the index revision procedure (odds ratio (OR) 0.24 (95% confidence interval (CI) 0.08 to 0.72); p = 0.008), a repeated DAIR within 90 days (OR 0.37 (95% CI 0.14 to 0.97); p = 0.040), and the use of an immunosuppressive agent (OR 0.13 (95% CI 0.02 to 0.67); p = 0.012) were associated with a significantly reduced success rate. In the culture-positive group, a mismatch between the antibiotic treatment and the susceptibility of the organism was associated with a significantly lower success rate (OR 0.13 (95% CI 0.03 to 0.62); p = 0.007). Conclusion. DAIR is an acceptable form of surgical treatment for patients with a suspected early PJI after revision arthroplasty of the hip or knee. DAIRs performed after a prolonged interval, multiple DAIRs, and antibiotic mismatches were significantly associated with an increased risk of failure. Optimization of the host immune response and the prevention of antibiotic mismatch are modifiable factors that may improve the outcome. The high rate of mismatches was an important finding, underlining the need for a review of the local microbiological data, which might improve the outcome. Cite this article: Bone Joint J 2022;104-B(4):464–471

Aims. With increasing burden of revision hip arthroplasty (THA), one of the major challenges is the management of proximal femoral bone loss associated with previous multiple surgeries. Proximal femoral arthroplasty (PFA) has already been popularized for tumour surgeries. Our aim was to describe the outcome of using PFA in these demanding non-neoplastic cases. Methods. A retrospective review of 25 patients who underwent PFA for non-neoplastic indications between January 2009 and December 2015 was undertaken. Their clinical and radiological outcome, complication rates, and survival were recorded. All patients had the Stanmore Implant – Modular Endo-prosthetic Tumour System (METS). Results. At mean follow-up of 5.9 years, there were no periprosthetic fractures. Clearance of infection was achieved in 63.6% of cases. One hip was re-revised to pseudo arthroplasty for deep infection. Instability was noted in eight of the hips (32%), of which seven needed further surgery. Out of these eight hips with instability, five had preoperative infection. Deep infection was noted in five of the hips (20%), of which four were primarily revised for infection. One patient had aseptic loosening of the femoral component and awaits revision surgery. The Kaplan-Meier survivorship free of revision of any component for any reason was 72% (95% confidence interval (CI) 51.3% to 92.7%), and for revisions of only femoral component for any reason was 96% (95% CI 86.3% to 105.7%) at five years. Conclusion. Dislocation and infection remain the major cause for failure, particularly in patients with pre-existing infection. The use of dual mobility cups, silver-coated implants, and less aggressive postoperative rehabilitation regimens would possibly aid in the reduction of complications. PFA performed in patients with periprosthetic fracture seem to fair better. This study supports the judicious use of PFA in non-oncological revision hip arthroplasties, and that they be performed by experienced revision arthroplasty surgeons. Cite this article: Bone Jt Open 2022;3(3):229–235

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

In recent years, machine learning (ML) and artificial neural networks (ANNs), a particular subset of ML, have been adopted by various areas of healthcare. A number of diagnostic and prognostic algorithms have been designed and implemented across a range of orthopaedic sub-specialties to date, with many positive results. However, the methodology of many of these studies is flawed, and few compare the use of ML with the current approach in clinical practice. Spinal surgery has advanced rapidly over the past three decades, particularly in the areas of implant technology, advanced surgical techniques, biologics, and enhanced recovery protocols. It is therefore regarded an innovative field. Inevitably, spinal surgeons will wish to incorporate ML into their practice should models prove effective in diagnostic or prognostic terms. The purpose of this article is to review published studies that describe the application of neural networks to spinal surgery and which actively compare ANN models to contemporary clinical standards allowing evaluation of their efficacy, accuracy, and relatability. It also explores some of the limitations of the technology, which act to constrain the widespread adoption of neural networks for diagnostic and prognostic use in spinal care. Finally, it describes the necessary considerations should institutions wish to incorporate ANNs into their practices. In doing so, the aim of this review is to provide a practical approach for spinal surgeons to understand the relevant aspects of neural networks. Cite this article: Bone Joint J 2021;103-B(9):1442–1448

Aims. This study aims to answer the following questions in patients with hip osteoarthritis (OA) who underwent total hip arthroplasty (THA): are patient-reported outcome measures (PROMs) affected by the location of the maximum severity of pain?; are PROMs affected by the presence of non-groin pain?; are PROMs affected by the severity of pain?; and are PROMs affected by the number of pain locations?. Methods. We reviewed 336 hips (305 patients) treated with THA for hip OA from December 2016 to November 2019 using pain location/severity questionnaires, modified Harris Hip Score (mHHS), Hip Outcome Score (HOS), international Hip Outcome Tool (iHOT-12) score, and radiological analysis. Descriptive statistics, analysis of covariance (ANCOVA), and Spearman partial correlation coefficients were used. Results. There was a significant difference in iHOT-12 scores between groups experiencing the most severe pain in the groin and the trochanter (p = 0.039). Additionally, more favourable mHHS scores were related to the presence of preoperative pain in trochanter (p = 0.049), lower back (p = 0.056), lateral thigh (p = 0.034), and posterior thigh (p = 0.005). Finally, the maximum severity of preoperative pain and number of pain locations had no significant relationship with PROMs (maximum severity: HHS: p = 0.928, HOS: p = 0.163, iHOT-12 p = 0.233; number of pain locations: HHS: p = 0.211; HOS: p = 0.801; iHOT-12: p = 0.112). Conclusion. Although there was a significant difference in iHOT-12 scores between patients with the most severe pain in the groin or trochanter, and the presence of pain in the trochanter, lower back, lateral thigh, or posterior thigh was related to higher mHHS scores, the majority of preoperative pain characteristics did not have a significant impact on outcomes. Therefore, a broad array of patients with hip OA might expect similar, favourable outcomes from THA notwithstanding preoperative pain characteristics. Cite this article: Bone Jt Open 2022;3(4):332–339

Aims. The goal of the current systematic review was to assess the impact of implant placement accuracy on outcomes following total knee arthroplasty (TKA). Methods. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the Ovid Medline, Embase, Cochrane Central, and Web of Science databases in order to assess the impact of the patient-reported outcomes measures (PROMs) and implant placement accuracy on outcomes following TKA. Studies assessing the impact of implant alignment, rotation, size, overhang, or condylar offset were included. Study quality was assessed, evidence was graded (one-star: no evidence, two-star: limited evidence, three-star: moderate evidence, four-star: strong evidence), and recommendations were made based on the available evidence. Results. A total of 49 studies were identified for inclusion. With respect to PROMs, there was two-star evidence in support of mechanical axis alignment (MAA), femorotibial angle (FTA), femoral coronal angle (FCA), tibial coronal angle (TCA), femoral sagittal angle (FSA), femoral rotation, tibial and combined rotation/mismatch, and implant size/overhang or offset on PROMs, and one-star evidence in support of tibial sagittal angle (TSA), impacting PROMs. With respect to survival, there was three- to four-star evidence in support FTA, FCA, TCA, and TSA, moderate evidence in support of femoral rotation, tibial and combined rotation/mismatch, and limited evidence in support of MAA, FSA, and implant size/overhang or offset impacting survival. Conclusion. Overall, there is limited evidence to suggest that PROMs are impacted by the accuracy of implant placement, and malalignment does not appear to be a significant driver of the observed high rates of patient dissatisfaction following TKA. However, FTA, FCA, TCA, TSA, and implant rotation demonstrate a moderate-strong relationship with implant survival. Efforts should be made to improve the accuracy of these parameters in order to improve TKA survival. Cite this article: Bone Joint J 2021;103-B(9):1449–1456