Aims. Dual-mobility (DM) components are increasingly used to prevent and treat dislocation after total hip arthroplasty (THA). Intraprosthetic dissociation (IPD) is a rare complication of DM that is believed to have decreased with contemporary implants. This study aimed to report incidence, treatment, and outcomes of contemporary DM IPD. Methods. A total of 1,453 DM components were implanted at a single academic institution between January 2010 and December 2021: 695 in primary and 758 in revision THA. Of these, 49 presented with a dislocation of the large DM head and five presented with an IPD. At the time of closed reduction of the large DM dislocation, six additional IPDs occurred. The mean age was 64 years (SD 9.6), 54.5% were female (n = 6), and mean follow-up was 4.2 years (SD 1.8). Of the 11 IPDs, seven had a history of instability, five had abductor insufficiency, four had prior lumbar fusion, and two were conversions for failed fracture management. Results. The incidence of IPD was 0.76%. Of the 11 IPDs, ten were missed either at presentation or after attempted reduction. All ten patients with a missed IPD were discharged with a presumed reduction. The mean time from IPD to surgical treatment was three weeks (0 to 23). One patient died after IPD prior to revision. Of the ten remaining hips with IPD, the DM head was exchanged in two, four underwent acetabular revision with DM exchange, and four were revised to a constrained liner. Of these, five (50%) underwent reoperation at a mean 1.8 years (SD 0.73), including one additional acetabular revision. No patients who underwent initial acetabular revision for IPD treatment required subsequent reoperation. Conclusion. The overall rate of IPD was low at 0.76%. It is essential to identify an IPD on radiographs as the majority were missed at presentation or after iatrogenic dissociation. Surgeons should consider acetabular revision for IPD to allow conversion to a larger DM head, and take care to remove impinging structures that may increase the risk of subsequent failure. Cite this article: Bone Joint J 2024;106-B(5 Supple B):98–104

Aims. Brace treatment is the cornerstone of managing developmental dysplasia of the hip (DDH), yet there is a lack of evidence-based treatment protocols, which results in wide variations in practice. To resolve this, we have developed a comprehensive nonoperative treatment protocol conforming to published consensus principles, with well-defined a priori criteria for inclusion and successful treatment. Methods. This was a single-centre, prospective, longitudinal cohort study of a consecutive series of infants with ultrasound-confirmed DDH who underwent a comprehensive nonoperative brace management protocol in a unified multidisciplinary clinic between January 2012 and December 2016 with five-year follow-up radiographs. The radiological outcomes were acetabular index-lateral edge (AI-L), acetabular index-sourcil (AI-S), centre-edge angle (CEA), acetabular depth ratio (ADR), International Hip Dysplasia Institute (IHDI) grade, and evidence of avascular necrosis (AVN). At five years, each hip was classified as normal (< 1 SD), borderline dysplastic (1 to 2 SDs), or dysplastic (> 2 SDs) based on validated radiological norm-referenced values. Results. Of 993 infants assessed clinically and sonographically, 21% (212 infants, 354 abnormal hips) had DDH and were included. Of these, 95% (202 infants, 335 hips) successfully completed bracing, and 5% (ten infants, 19 hips) failed bracing due to irreducible hip(s). The success rate of bracing for unilateral dislocations was 88% (45/51 infants) and for bilateral dislocations 83% (20/24 infants). The femoral nerve palsy rate was 1% (2/212 infants). At five-year follow-up (mean 63 months (SD 5.9; 49 to 83)) the prevalence of residual dysplasia after successful brace treatment was 1.6% (5/312 hips). All hips were IHDI grade I and none had AVN. Four children (4/186; 2%) subsequently underwent surgery for residual dysplasia. Conclusion. Our comprehensive protocol for nonoperative treatment of infant DDH has shown high rates of success and extremely low rates of residual dysplasia at a mean age of five years. Cite this article: Bone Joint J 2023;105-B(8):935–942

Aims. There is a lack of published evidence relating to the rate of nonunion seen in occult scaphoid fractures, diagnosed only after MRI. This study reports the rate of delayed union and nonunion in a cohort of patients with MRI-detected acute scaphoid fractures. Methods. This multicentre cohort study at eight centres in the UK included all patients with an acute scaphoid fracture diagnosed on MRI having presented acutely following wrist trauma with normal radiographs. Data were gathered retrospectively for a minimum of 12 months at each centre. The primary outcome measures were the rate of acute surgery, delayed union, and nonunion. Results. A total of 1,989 patients underwent acute MRI for a suspected scaphoid fracture during the study period, of which 256 patients (12.9%) were diagnosed with a previously occult scaphoid fracture. Of the patients with scaphoid fractures, six underwent early surgical fixation (2.3%) and there was a total of 16 cases of delayed or nonunion (6.3%) in the remaining 250 patients treated with cast immobilization. Of the nine nonunions (3.5%), seven underwent surgery (2.7%), one opted for non-surgical treatment, and one failed to attend follow-up. Of the seven delayed unions (2.7%), one (0.4%) was treated with surgery at two months, one (0.4%) did not attend further follow-up, and the remaining five fractures (1.9%) healed after further cast immobilization. All fractures treated with surgery had united at follow-up. There was one complication of surgery (prominent screw requiring removal). Conclusion. MRI-detected scaphoid fractures are not universally benign, with delayed or nonunion of scaphoid fractures diagnosed only after MRI seen in over 6% despite appropriate initial immobilization, with most of these patients with nonunion requiring surgery to achieve union. This study adds weight to the evidence base supporting the use of early MRI for these patients. Cite this article: Bone Joint J 2024;106-B(4):387–393

Aims. Periprosthetic joint infection (PJI) is a challenging complication of any arthroplasty procedure. We reviewed our use of static antibiotic-loaded cement spacers (ABLCSs) for staged management of PJI where segmental bone loss, ligamentous instability, or soft-tissue defects necessitate a static construct. We reviewed factors contributing to their failure and techniques to avoid these complications when using ABLCSs in this context. Methods. A retrospective analysis was conducted of 94 patients undergoing first-stage revision of an infected knee prosthesis between September 2007 and January 2020 at a single institution. Radiographs and clinical records were used to assess and classify the incidence and causes of static spacer failure. Of the 94 cases, there were 19 primary total knee arthroplasties (TKAs), ten revision TKAs (varus-valgus constraint), 20 hinged TKAs, one arthrodesis (nail), one failed spacer (performed elsewhere), 21 distal femoral endoprosthetic arthroplasties, and 22 proximal tibial arthroplasties. Results. A total of 35/94 patients (37.2%) had spacer-related complications, of which 26/35 complications (74.3%) were because of mechanical failure of the spacer construct, while 9/35 (25.7%) were due to recurrence of infection. Risk factors for internal failure were a construct where the total intramedullary spacer length was less than twice the length of the central osseous defect (p = 0.009), where proximal or distal intraosseous spacer contact was < 10%, and after tibial tubercle osteotomy (p = 0.005). The incidence of spacer complications significantly increased the time to second stage: mean 157 days (42 to 458) in those without complications versus 227 days (11 to 528) with complications (p = 0.014). Conclusion. The failure rate of static antibiotic-loaded cement spacers is much higher than anticipated. Complications of the spacer significantly increased the time to second-stage revision. The risk of mechanical failure is significantly increased if the spacer is less than double the size of the segmental defect, or if inadequate reinforcement is inserted into the residual bone. These findings serve as a guide for surgeons to avoid mechanical complications with static spacers. Cite this article: Bone Joint J 2024;106-B(10):1067–1073

Aims. Robotic arm-assisted surgery offers accurate and reproducible guidance in component positioning and assessment of soft-tissue tensioning during knee arthroplasty, but the feasibility and early outcomes when using this technology for revision surgery remain unknown. The objective of this study was to compare the outcomes of robotic arm-assisted revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) versus primary robotic arm-assisted TKA at short-term follow-up. Methods. This prospective study included 16 patients undergoing robotic arm-assisted revision of UKA to TKA versus 35 matched patients receiving robotic arm-assisted primary TKA. In all study patients, the following data were recorded: operating time, polyethylene liner size, change in haemoglobin concentration (g/dl), length of inpatient stay, postoperative complications, and hip-knee-ankle (HKA) alignment. All procedures were performed using the principles of functional alignment. At most recent follow-up, range of motion (ROM), Forgotten Joint Score (FJS), and Oxford Knee Score (OKS) were collected. Mean follow-up time was 21 months (6 to 36). Results. There were no differences between the two treatment groups with regard to mean change in haemoglobin concentration (p = 0.477), length of stay (LOS, p = 0.172), mean polyethylene thickness (p = 0.065), or postoperative complication rates (p = 0.295). At the most recent follow-up, the primary robotic arm-assisted TKA group had a statistically significantly improved OKS compared with the revision UKA to TKA group (44.6 (SD 2.7) vs 42.3 (SD 2.5); p = 0.004) but there was no difference in the overall ROM (p = 0.056) or FJS between the two treatment groups (86.1 (SD 9.6) vs 84.1 (4.9); p = 0.439). Conclusion. Robotic arm-assisted revision of UKA to TKA was associated with comparable intraoperative blood loss, early postoperative rehabilitation, functional outcomes, and complications to primary robotic TKA at short-term follow-up. Robotic arm-assisted surgery offers a safe and reproducible technique for revising failed UKA to TKA. Cite this article: Bone Joint J 2024;106-B(7):680–687

Aims. Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis). Methods. Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system. Results. At a mean follow-up of 90 months (64 to 130), only two out of 245 cases failed due to aseptic loosening. Intraoperative grading yielded mean scores of 1.87 (95% confidence interval (CI) 1.82 to 1.92) for the femur and 1.96 (95% CI 1.92 to 2.0) for the tibia. Only 3.7% of femoral and 1.7% of tibial reconstructions fell below the 1.5-point threshold, which included the two cases of aseptic loosening. Interobserver reliability for postoperative radiological grading was 0.97 for the femur and 0.85 for the tibia. Conclusion. A minimum score of 1.5 points for each skeletal segment appears to be a reasonable cut-off to define sufficient fixation in rTKA. There were no revisions for aseptic loosening at mid-term follow-up when this fixation threshold was achieved or exceeded. When assessing first-time revisions, this novel grading system has shown excellent intra- and interobserver reliability. Cite this article: Bone Joint J 2024;106-B(5):468–474

Aims. Acetabular fractures are associated with long-term morbidity. Our prospective cohort study sought to understand the recovery trajectory of this injury over five years. Methods. Eligible patients at a level I trauma centre were recruited into a longitudinal registry of surgical acetabular fractures between June 2004 and August 2019. Patient-reported outcome measures (PROMs), including the 36-Item Short Form Health Survey (SF-36) physical component summary (PCS), were recorded at baseline pre-injury recall and six months, one year, two years, and five years postoperatively. Comparative analyses were performed for elementary and associated fracture patterns. The proportion of patients achieving minimal clinically important difference (MCID) was determined. The rate of, and time to, conversion to total hip arthroplasty (THA) was also established. Results. We recruited 251 patients (253 fractures), with a 4:1 male to female ratio and mean age of 46.1 years (SD 16.4). Associated fracture patterns accounted for 56.5% of fractures (n = 143). Trajectory analysis showed all timepoints had significant disability versus baseline, including final follow-up (p < 0.001). Elementary fractures had higher SF-36 PCS at six months (p = 0.023) and one year (p = 0.007) compared to associated fractures, but not at two years (p = 0.135) or five years (p = 0.631). The MCID in SF-36 PCS was observed in 37.3% of patients (69/185) between six months and one year, 26.9% of patients (39/145) between one and two years, and 23.3% of patients (20/86) between two and five years, highlighting the long recovery potential of these injuries. A significant proportion of patients failed to attain the MCID after five years (38.1%; 40/105). Conversion to THA occurred in 13.1% of patients (11/110 elementary and 22/143 associated fractures). Approximately two-thirds of THAs (21/33 patients; 63.6%) were performed within two years of index surgery. Conclusion. Acetabular fractures significantly impact physical function. Recovery trajectory is often elongated beyond one year, with two-thirds of our patients displaying persistent clinically relevant long-term disability. Cite this article: Bone Joint J 2024;106-B(1):69–76

Aims. One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure. Methods. We retrospectively reviewed all repeat one-stage revision THAs performed after failed one-stage exchange THA for infection between January 2008 and December 2016. The final cohort included 32 patients. The mean follow-up after repeat one-stage exchange was 5.3 years (1.2 to 13.0). The patients with a further infection-related failure and/or all-cause revision were reported, and Kaplan-Meier survival for these endpoints determined. Patients were categorized according to the MSIS system, and its association with further infection was analyzed. Results. A total of eight repeat septic revisions (25%) developed a further infection-related failure, and the five-year infection-free survival was 81% (95% confidence interval (CI) 57 to 92). Nine (28%) underwent a further all-cause revision and the five-year all-cause revision-free survival was 74% (95% CI 52 to 88). Neither the MSIS classification of the host status (p = 0.423) nor the limb status (p = 0.366) was significantly associated with further infection-related failure. Conclusion. Repeat one-stage exchange for PJI in THA is associated with a favourable five-year infection-free and all-cause revision-free survival. Notably, the rate of infection control is encouraging when compared with the reported rates after repeat two-stage exchange. The results can be used to counsel patients and help clinicians make informed decisions about treatment. With the available number of patients, further infection-related failure was not associated with the MSIS host or limb status. Cite this article: Bone Joint J 2022;104-B(1):27–33

Aims. Clinical management of open fractures is challenging and frequently requires complex reconstruction procedures. The Gustilo-Anderson classification lacks uniform interpretation, has poor interobserver reliability, and fails to account for injuries to musculotendinous units and bone. The Ganga Hospital Open Injury Severity Score (GHOISS) was designed to address these concerns. The major aim of this review was to ascertain the evidence available on accuracy of the GHOISS in predicting successful limb salvage in patients with mangled limbs. Methods. We searched electronic data bases including PubMed, CENTRAL, EMBASE, CINAHL, Scopus, and Web of Science to identify studies that employed the GHOISS risk tool in managing complex limb injuries published from April 2006, when the score was introduced, until April 2021. Primary outcome was the measured sensitivity and specificity of the GHOISS risk tool for predicting amputation at a specified threshold score. Secondary outcomes included length of stay, need for plastic surgery, deep infection rate, time to fracture union, and functional outcome measures. Diagnostic test accuracy meta-analysis was performed using a random effects bivariate binomial model. Results. We identified 1,304 records, of which six prospective cohort studies and two retrospective cohort studies evaluating a total of 788 patients were deemed eligible for inclusion. A diagnostic test meta-analysis conducted on five cohort studies, with 474 participants, showed that GHOISS at a threshold score of 14 has a pooled sensitivity of 93.4% (95% confidence interval (CI) 78.4 to 98.2) and a specificity of 95% (95% CI 88.7 to 97.9) for predicting primary or secondary amputations in people with complex lower limb injuries. Conclusion. GHOISS is highly accurate in predicting success of limb salvage, and can inform management and predict secondary outcomes. However, there is a need for high-quality multicentre trials to confirm these findings and investigate the effectiveness of the score in children, and in predicting secondary amputations. Cite this article: Bone Joint J 2023;105-B(1):21–28

Aims. Cutibacterium acnes (C. acnes; previously known as Propionibacterium acnes or P. acnes) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee. Methods. Patients with C. acnes PJI between January 2005 and December 2018 were retrospectively reviewed utilizing the institutional total joint registry. Patients with monomicrobial PJI and two or more positive cultures were considered to have true C. acnes PJI. Patients with polymicrobial infection or with only one positive culture were excluded. This resulted in 35 PJIs (21 hips and 14 knees); the patients’ mean age was 63 years (35 to 84) and 15 (43%) were female. Mean follow-up was five years (1 to 14). Results. The median time to positive culture was five days (IQR 5 to 6) and median synovial fluid cell count was 22,583 cells (IQR 15,200 to 53,231). The median ESR was 25 mm/hr (IQR 7 to 37), and CRP was 15 mg/l (IQR 3 to 29). Of the 35 PJIs, 18 (51%) were treated with chronic antibiotic suppression without surgical intervention, and the remainder were treated with two-stage exchange arthroplasty. The two-year survival free of any revision was 94%. Four patients failed treatment due to symptomatic infection, with three treated with two-stage exchange and one treated with irrigation and debridement with modular component exchange for a survival rate of 89% and 83% at two and five years, respectively. Conclusion. Laboratory evidence of C. acnes PJI in this cohort was typical compared to more conventional organisms. Cultures grew more quickly than previously thought in patients with C. acnes PJI. Treatment with two-stage exchange or chronic antibiotic suppression alone both had few treatment failures at mid-term follow-up. Cite this article: Bone Joint J 2024;106-B(12):1426–1430

Aims. The aim of this study was to evaluate the outcome of complex radial head fractures at mid-term follow-up, and determine whether open reduction and internal fixation (ORIF) or radial head arthroplasty (RHA) should be recommended for surgical treatment. Methods. Patients who underwent surgery for complex radial head fractures (Mason type III, ≥ three fragments) were divided into two groups (ORIF and RHA) and propensity score matching was used to individually match patients based on patient characteristics. Ultimately, 84 patients were included in this study. After a mean follow-up of 4.1 years (2.0 to 9.5), patients were invited for clinical and radiological assessment. The Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire score were evaluated. Results. Patients treated with ORIF showed significantly better postoperative range of motion for flexion and extension (121.1° (SD 16.4°) vs 108.1° (SD 25.8°); p = 0.018). Postoperative functional scores also showed significantly better results in the ORIF group (MEPS 90.1 (SD 13.6) vs 78 (SD 20.5); p = 0.004). There was no significant difference between the groups in terms of the complication rate (RHA 23.8% (n = 10) vs ORIF 26.2% (n = 11)). Implant-related complications occurred in six cases (14.3%) in the RHA group and in five cases (11.9%) in the ORIF group. Conclusion. Irrespective of the patient’s age, sex, type of injury, or number of fracture fragments, ORIF of the radial head should be attempted initially, if a stable reconstruction can be achieved, as it seems to provide a superior postoperative outcome for the patient compared to primary RHA. If reconstruction is not feasible, RHA is still a viable alternative. In the surgical treatment of complex radial head fractures, reconstruction shows superior postoperative outcomes compared to RHA. Good postoperative results can be achieved even after failed reconstruction and conversion to secondary RHA. Therefore, we encourage surgeons to favour reconstruction of complex radial head fractures, regardless of injury type or number of fragments, as long as a stable fixation can be achieved. Cite this article: Bone Joint J 2024;106-B(10):1158–1164

Aims. Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity. Methods. We retrospectively reviewed 32 patients (22 hips and 11 knees) who underwent single-stage revision combined with IA carbapenem infusion between November 2013 and March 2020. The IA and intravenous (IV) carbapenem infusions were administered for a single Gram-negative infection, and IV vancomycin combined with IA carbapenems and vancomycin was applied for polymicrobial infection including Gram-negative bacteria. The bacterial community distribution, drug sensitivity, infection control rate, functional recovery, and complications were evaluated. Reinfection or death caused by PJI was regarded as a treatment failure. Results. Gram-negative PJI was mainly caused by Escherichia coli (8/34), Enterobacter cloacae (7/34), and Klebsiella pneumoniae (5/34). Seven cases (7/32) involved polymicrobial PJIs. The resistance rates of penicillin, cephalosporin, quinolones, and sulfonamides were > 10%, and all penicillin and partial cephalosporins (first and second generation) were > 30%. Of 32 cases, treatment failed to eradicate infection in only three cases (9.4%), at a mean follow-up of 55.1 months (SD 25 to 90). The mean postoperative Harris Hip Score and Hospital for Special Surgery knee score at the most recent follow-up were 81 (62 to 91) and 79 (56 to 89), respectively. One patient developed a fistula, and another presented with a local rash on an infected joint. Conclusion. The use of IA carbapenem delivered alongside one-stage revision effectively controlled Gram-negative infection and obtained acceptable clinical outcomes with few complications. Notably, first- and second-generation cephalosporins and penicillin should be administrated with caution, due to a high incidence of resistance. Cite this article: Bone Joint J 2023;105-B(3):284–293

Aims. The aim of this study was to compare a bicruciate-retaining (BCR) total knee arthroplasty (TKA) with a posterior cruciate-retaining (CR) TKA design in terms of kinematics, measured using fluoroscopy and stability as micromotion using radiostereometric analysis (RSA). Methods. A total of 40 patients with end-stage osteoarthritis were included in this randomized controlled trial. All patients performed a step-up and lunge task in front of a monoplane fluoroscope one year postoperatively. Femorotibial contact point (CP) locations were determined at every flexion angle and compared between the groups. RSA images were taken at baseline, six weeks, three, six, 12, and 24 months postoperatively. Clinical and functional outcomes were compared postoperatively for two years. Results. The BCR-TKA demonstrated a kinematic pattern comparable to the natural knee’s screw-home mechanism in the step-up task. In the lunge task, the medial CP of the BCR-TKA was more anterior in the early flexion phase, while laterally the CP was more posterior during the entire movement cycle. The BCR-TKA group showed higher tibial migration. No differences were found for the clinical and functional outcomes. Conclusion. The BCR-TKA shows a different kinematic pattern in early flexion/late extension compared to the CR-TKA. The difference between both implants is mostly visible in the flexion phase in which the anterior cruciate ligament is effective; however, both designs fail to fully replicate the motion of a natural knee. The higher migration of the BCR-TKA was concerning and highlights the importance of longer follow-up. Cite this article: Bone Joint J 2023;105-B(1):35–46

Aims. Children with spinal dysraphism can develop various musculoskeletal deformities, necessitating a range of orthopaedic interventions, causing significant morbidity, and making considerable demands on resources. This systematic review aimed to identify what outcome measures have been reported in the literature for children with spinal dysraphism who undergo orthopaedic interventions involving the lower limbs. Methods. A PROSPERO-registered systematic literature review was performed following PRISMA guidelines. All relevant studies published until January 2023 were identified. Individual outcomes and outcome measurement tools were extracted verbatim. The measurement tools were assessed for reliability and validity, and all outcomes were grouped according to the Outcome Measures Recommended for use in Randomized Clinical Trials (OMERACT) filters. Results. From 91 eligible studies, 27 individual outcomes were identified, including those related to clinical assessment (n = 12), mobility (n = 4), adverse events (n = 6), investigations (n = 4), and miscellaneous (n = 1). Ten outcome measurement tools were identified, of which Hoffer’s Functional Ambulation Scale was the most commonly used. Several studies used unvalidated measurement tools originally developed for other conditions, and 26 studies developed new measurement tools. On the OMERACT filter, most outcomes reported pathophysiology and/or the impact on life. There were only six patient- or parent-reported outcomes, and none assessed the quality of life. Conclusion. The outcomes that were reported were heterogenous, lack validation and failed to incorporate patient or family perceptions. Until outcomes can be reported unequivocally, research in this area will remain limited. Our findings should guide the development of a core outcome set, which will allow consistency in the reporting of outcomes for this condition. Cite this article: Bone Joint J 2024;106-B(3):277–285

Aims. The aims of this study were to determine the incidence and factors for developing periprosthetic joint infection (PJI) following hemiarthroplasty (HA) for hip fracture, and to evaluate treatment outcome and identify factors associated with treatment outcome. Methods. A retrospective review was performed of consecutive patients treated for HA PJI at a tertiary referral centre with a mean 4.5 years’ follow-up (1.6 weeks to 12.9 years). Surgeries performed included debridement, antibiotics, and implant retention (DAIR) and single-stage revision. The effect of different factors on developing infection and treatment outcome was determined. Results. A total of 1,984 HAs were performed during the study period, and 44 sustained a PJI (2.2%). Multiple logistic regression analysis revealed that a higher CCI score (odds ratio (OR) 1.56 (95% confidence interval (CI) 1.117 to 2.187); p = 0.003), peripheral vascular disease (OR 11.34 (95% CI 1.897 to 67.810); p = 0.008), cerebrovascular disease (OR 65.32 (95% CI 22.783 to 187.278); p < 0.001), diabetes (OR 4.82 (95% CI 1.903 to 12.218); p < 0.001), moderate-to-severe renal disease (OR 5.84 (95% CI 1.116 to 30.589); p = 0.037), cancer without metastasis (OR 6.42 (95% CI 1.643 to 25.006); p = 0.007), and metastatic solid tumour (OR 15.64 (95% CI 1.499 to 163.087); p = 0.022) were associated with increasing PJI risk. Upon final follow-up, 17 patients (38.6%) failed initial treatment and required further surgery for HA PJI. One-year mortality was 22.7%. Factors associated with treatment outcome included lower preoperative Hgb level (97.9 g/l (SD 11.4) vs 107.0 g/l (SD 16.1); p = 0.009), elevated CRP level (99.1 mg/l (SD 63.4) vs 56.6 mg/l (SD 47.1); p = 0.030), and type of surgery. There was lower chance of success with DAIR (42.3%) compared to revision HA (66.7%) or revision with conversion to total hip arthroplasty (100%). Early-onset PJI (≤ six weeks) was associated with a higher likelihood of treatment failure (OR 3.5 (95% CI 1.2 to 10.6); p = 0.007) along with patients treated by a non-arthroplasty surgeon (OR 2.5 (95% CI 1.2 to 5.3); p = 0.014). Conclusion. HA PJI initially treated with DAIR is associated with poor chances of success and its value is limited. We strongly recommend consideration of a single-stage revision arthroplasty with cemented components. Cite this article: Bone Jt Open 2022;3(12):924–932

Aims. Prophylactic antibiotic regimens for elective primary total hip and knee arthroplasty vary widely across hospitals and trusts in the UK. This study aimed to identify antibiotic prophylaxis regimens currently in use for elective primary arthroplasty across the UK, establish variations in antibiotic prophylaxis regimens and their impact on the risk of periprosthetic joint infection (PJI) in the first-year post-index procedure, and evaluate adherence to current international consensus guidance. Methods. The guidelines for the primary and alternative recommended prophylactic antibiotic regimens in clean orthopaedic surgery (primary arthroplasty) for 109 hospitals and trusts across the UK were sought by searching each trust and hospital’s website (intranet webpages), and by using the MicroGuide app. The mean cost of each antibiotic regimen was calculated using price data from the British National Formulary (BNF). Regimens were then compared to the 2018 Philadelphia Consensus Guidance, to evaluate adherence to international guidance. Results. The primary choice and dosing of the prophylactic antimicrobial regimens varied widely. The two most used regimens were combined teicoplanin and gentamicin, and cefuroxime followed by two or three doses of cefuroxime eight-hourly, recommended by 24 centres (22.02%) each. The alternative choice and dosing of the prophylactic antimicrobial regimen also varied widely across the 83 centres with data available. Prophylaxis regimens across some centres fail to cover the likeliest causes of surgical site infection (SSI). Five centres (4.59%) recommend co-amoxiclav, which confers no Staphylococcus coverage, while 33 centres (30.28%) recommend cefuroxime, which confers no Enterococcus coverage. Limited adherence to 2018 Philadelphia Consensus Guidance was observed, with 67 centres (61.50%) not including a cephalosporin in their guidance. Conclusion. This analysis of guidance on antimicrobial prophylaxis in primary arthroplasty across 109 hospitals and trusts in the UK has identified widespread variation in primary and alternative antimicrobial regimens currently recommended. Cite this article: Bone Jt Open 2023;4(10):742–749

Aims. Tissue inhibitors of metalloproteinases (TIMPs) are the endogenous inhibitors of the zinc-dependent matrix metalloproteinases (MMP) and A disintegrin and metalloproteinases (ADAM) involved in extracellular matrix modulation. The present study aims to develop the TIMPs as biologics for osteoclast-related disorders. Methods. We examine the inhibitory effect of a high affinity, glycosyl-phosphatidylinositol-anchored TIMP variant named ‘T1. PrαTACE. ’ on receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced osteoclast differentiation. Results. Osteoclast progenitor cells transduced with T1. PrαTACE. failed to form tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts or exhibit bone-resorbing activity following treatment with RANKL. At the messenger RNA level, T1. PrαTACE. strongly attenuated expression of key osteoclast marker genes that included TRAP, cathepsin K, osteoclast stimulatory transmembrane protein (OC-STAMP), dendritic cell-specific transmembrane protein (DC-STAMP), osteoclast-associated receptor (OSCAR), and ATPase H. +. -transporting V0 subunit d2 (ATP6V0D2) by blocking autoamplification of nuclear factor of activated T cells 1 (NFATc1), the osteoclastogenic transcription factor. T1. PrαTACE. selectively extended p44/42 mitogen-activated protein kinase activation, an action that may have interrupted terminal differentiation of osteoclasts. Inhibition studies with broad-spectrum hydroxamate inhibitors confirmed that the anti-resorptive activity of T1. PrαTACE. was not reliant on its metalloproteinase-inhibitory activity. Conclusion. T1. PrαTACE. disrupts the RANKL-NFATc1 signalling pathway, which leads to osteoclast dysfunction. As a novel candidate in the prevention of osteoclastogenesis, the TIMP could potentially be developed for the treatment of osteoclast-related disorders such as osteoporosis. Cite this article: Bone Joint Res 2022;11(11):763–776

Aims. This study aims to report the outcomes in the treatment of unstable proximal third scaphoid nonunions with arthroscopic curettage, non-vascularized bone grafting, and percutaneous fixation. Methods. This was a retrospective analysis of 20 patients. All cases were delayed presentations (n = 15) or failed nonoperatively managed scaphoid fractures (n = 5). Surgery was performed at a mean duration of 27 months (7 to 120) following injury with arthroscopic debridement and arthroscopic iliac crest autograft. Fracture fixation was performed percutaneously with Kirschner (K)-wires in 12 wrists, a headless screw in six, and a combination of a headless screw and single K-wire in two. Clinical outcomes were assessed using grip strength, patient-reported outcome measures, and wrist range of motion (ROM) measurements. Results. Intraoperatively, established avascular necrosis of the proximal fragment was identified in ten scaphoids. All fractures united within 16 weeks, confirmed by CT. At a mean follow-up of 31 months (12 to 64), there were significant improvements in the Patient-Rated Wrist Evaluation, Mayo Wrist Score, abbreviated Disabilities of the Arm, Shoulder and Hand score, wrist ROM, grip strength, and the patients’ subjective pain score. No peri- or postoperative complications were encountered. Conclusion. Our data indicate that arthroscopic bone grafting and fixation with cancellous autograft is a viable method in the treatment of proximal third scaphoid nonunions, regardless of the vascularity of the proximal fragment. Cite this article: Bone Joint J 2022;104-B(8):946–952

Aims. This study was performed to explore the effect of melatonin on pyroptosis in nucleus pulposus cells (NPCs) and the underlying mechanism of that effect. Methods. This experiment included three patients diagnosed with lumbar disc herniation who failed conservative treatment. Nucleus pulposus tissue was isolated from these patients when they underwent surgical intervention, and primary NPCs were isolated and cultured. Western blotting, reverse transcription polymerase chain reaction, fluorescence staining, and other methods were used to detect changes in related signalling pathways and the ability of cells to resist pyroptosis. Results. Western blot analysis confirmed the expression of cleaved CASP-1 and melatonin receptor (MT-1A-R) in NPCs. The cultured NPCs were identified by detecting the expression of CD24, collagen type II, and aggrecan. After treatment with hydrogen peroxide, the pyroptosis-related proteins NLR family pyrin domain containing 3 (NLRP3), cleaved CASP-1, N-terminal fragment of gasdermin D (GSDMD-N), interleukin (IL)-18, and IL-1β in NPCs were upregulated, and the number of propidium iodide (PI)-positive cells was also increased, which was able to be alleviated by pretreatment with melatonin. The protective effect of melatonin on pyroptosis was blunted by both the melatonin receptor antagonist luzindole and the nuclear factor erythroid 2–related factor 2 (Nrf2) inhibitor ML385. In addition, the expression of the transcription factor Nrf2 was up- or downregulated when the melatonin receptor was activated or blocked by melatonin or luzindole, respectively. Conclusion. Melatonin protects NPCs against reactive oxygen species-induced pyroptosis by upregulating the transcription factor Nrf2 via melatonin receptors. Cite this article: Bone Joint Res 2023;12(3):202–211

Aims. The Vantage Total Ankle System is a fourth-generation low-profile fixed-bearing implant that has been available since 2016. We aimed to describe our early experience with this implant. Methods. This is a single-centre retrospective review of patients who underwent primary total ankle arthroplasty (TAA) with a Vantage implant between November 2017 and February 2020, with a minimum of two years’ follow-up. Four surgeons contributed patients. The primary outcome was reoperation and revision rate of the Vantage implant at two years. Secondary outcomes included radiological alignment, peri-implant complications, and pre- and postoperative patient-reported outcomes. Results. There were 168 patients (171 ankles) included with a mean follow-up of 2.81 years (2 to 4.6) and mean age of 63.0 years (SD 9.4). Of the ten ankles with implant failure (5.8%), six had loosening of the tibial component. In the remaining four failed implants, one was due to periprosthetic joint infection (PJI), one was due to loosening of the talar component, and two were due to loosening of both the tibial and talar components. Seven patients underwent reoperation: irrigation and debridement for superficial infection (n = 4); bone grafting for cysts (n = 2); and open reduction internal fixation (n = 1). Asymptomatic peri-implant lucency/subsidence occurred in 20.1% of ankles, with the majority involving the tibial component (n = 25). There were statistically significant improvements in PROMs in all domains. Conclusion. Short-term results of this implant demonstrate early survival comparable to the reported survivorship of similar low-profile, non-stemmed implants. Radiological lucency occurred more commonly at the tibial component, and revisions occurred primarily due to loosening of the tibial component. Further research is needed to evaluate longer-term survivorship. Cite this article: Bone Joint J 2023;105-B(10):1099–1107