Aims. We present the development of a day-case total hip arthroplasty (THA) pathway in a UK National Health Service institution in conjunction with an extensive evidence-based summary of the interventions used to achieve successful day-case THA to which the protocol is founded upon. Methods. We performed a prospective audit of day-case THA in our institution as we reinitiate our full capacity elective services. In parallel, we performed a review of the literature reporting complication or readmission rates at ≥ 30-day postoperative following day-case THA. Electronic searches were performed using four databases from the date of inception to November 2020. Relevant studies were identified, data extracted, and qualitative synthesis performed. Results. Our evaluation and critique of the evidence-based literature identifies day-case THA to be safe, effective, and economical, benefiting both patients and healthcare systems alike. We further validate this with our institutional elective day surgery arthroplasty pathway (EDSAP) and report a small cohort of successful day-case THA cases as an example in the early stages of this practice in our unit. Conclusion. Careful patient selection and education, adequate perioperative considerations, including multimodal analgesia, surgical technique and blood loss management protocols and appropriate postoperative pathways comprising reliable discharge criteria are essential for successful day-case THA. Cite this article: Bone Jt Open 2021;2(2):93–102

Aims. Torus fractures are the most common childhood fracture, accounting for 500,000 UK emergency attendances per year. UK treatment varies widely due to lack of scientific evidence. This is the protocol for a randomized controlled equivalence trial of ‘the offer of a soft bandage and immediate discharge’ versus ‘rigid immobilization and follow-up as per the protocol of the treating centre’ in the treatment of torus fractures . Methods. Children aged four to 15-years-old inclusive who have sustained a torus/buckle fracture of the distal radius with/without an injury to the ulna are eligible to take part. Baseline pain as measured by the Wong Baker FACES pain scale, function using the Patient-Reported Outcomes Measurement Information System (PROMIS) upper limb, and quality of life (QoL) assessed with the EuroQol EQ-5D-Y will be collected. Each patient will be randomly allocated (1:1, stratified by centre and age group (four to seven years and ≥ eight years) to either a regimen of the offer of a soft bandage and immediate discharge or rigid immobilization and follow-up as per the protocol of the treating centre. Results. At day one, three, and seven, data on pain, function, QoL, immobilization, and analgesia will be collected. Three and six weeks after injury, the main outcomes plus data on complications, resource use, and school absence will be collected. The primary outcome is the Wong-Baker FACES pain scale at three days post-randomization. All data will be obtained through electronic questionnaires completed by the participants and/or parents/guardian. Cite this article: Bone Joint Open 2020;1-6:214–221

Aims. To assess the safety of tranexamic acid (TXA) in a large cohort of patients aged over 65 years who have sustained a hip fracture, with a focus on transfusion rates, mortality, and thromboembolic events. Methods. This is a consecutive cohort study with prospectively collected registry data. Patients with a hip fracture in the Region of Southern Denmark were included over a two-year time period (2015 to 2017) with the first year constituting a control group. In the second year, perioperative TXA was introduced as an intervention. Outcome was transfusion frequency, 30-day and 90-day mortality, and thromboembolic events. The latter was defined as any diagnosis or death due to arterial or venous thrombosis. The results are presented as relative risk (RR) and hazard ratio (HR) with 95% confidence intervals (CIs). Results. A total of 3,097 patients were included: 1,558 in the control group and 1,539 in the TXA group.31% (n = 477) of patients had transfusions in the control group compared to 27% (n = 405) in the TXA group yielding an adjusted RR of 0.83 (95% CI 0.75 to 0.91). TXA was not associated with increased 30-day mortality with an adjusted HR of 1.10 (95% CI 0.88 to 1.39) compared to the control group as well as no association with increased risk of 90-day mortality with a per protocol adjusted HR of 1.24 (95% CI 0.93 to 1.66). TXA was associated with a lower risk of thromboembolic events after 30 days (RR 0.63 (95% CI 0.42 to 0.93)) and 90 days (RR 0.72 (95% CI 0.52 to 0.99)). A subanalysis on haemoglobin demonstrated a median 17.7 g/L (interquartile range (IQR) 11.3 to 27.3) decrease in the control group compared to 17.7 g/L (IQR 9.7 to 25.8) in the per protocol TXA group (p = 0.060 on group level difference). Conclusion. TXA use in patients with a hip fracture, was not associated with an increased risk of mortality but was associated with lower transfusion rate and reduced thromboembolic events. Thus, we conclude that it is safe to use TXA in this patient group. Cite this article: Bone Joint J 2021;103-B(3):449–455

Aims. Large-diameter metal-on-metal (MoM) total hip arthroplasty (THA) has demonstrated unexpected high failure rates and pseudotumour formation. The purpose of this prospective cohort study is to report ten-year results in order to establish revision rate, prevalence of pseudotumour formation, and relation with whole blood cobalt levels. Methods. All patients were recalled according to the guidelines of the Dutch Orthopaedic Association. They underwent clinical and radiographical assessments (radiograph and CT scan) of the hip prosthesis and whole blood cobalt ion measurements. Overall, 94 patients (95 hips) fulfilled our requirements for a minimum ten-year follow-up. Results. Mean follow-up was 10.9 years (10 to 12), with a cumulative survival rate of 82.4%. Reason for revision was predominantly pseudotumour formation (68%), apart from loosening, pain, infection, and osteolysis. The prevalence of pseudotumour formation around the prostheses was 41%, while our previous report of this cohort (with a mean follow-up of 3.6 years) revealed a 39% prevalence. The ten-year revision-free survival with pseudotumour was 66.7% and without pseudotumour 92.4% (p < 0.05). There was poor discriminatory ability for cobalt for pseudotumour formation. Conclusion. This prospective study reports a minimum ten-year follow-up of large-head MoM THA. Revision rates are high, with the main reason being the sequelae of pseudotumour formation, which were rarely observed after five years of implantation. Blood ion measurements show limited discriminatory capacity in diagnosing pseudotumour formation. Our results evidence that an early comprehensive follow-up strategy is essential for MoM THA to promptly identify and manage early complications and revise on time. After ten years follow-up, we do not recommend continuing routine CT scanning or whole cobalt blood measurements, but instead enrolling these patients in routine follow-up protocols for THA. Cite this article: Bone Jt Open 2022;3(1):61–67

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. Despite recent literature questioning their use, vancomycin and clindamycin often substitute cefazolin as the preoperative antibiotic prophylaxis in primary total knee arthroplasty (TKA), especially in the setting of documented allergy to penicillin. Topical povidone-iodine lavage and vancomycin powder (VIP) are adjuncts that may further broaden antimicrobial coverage, and have shown some promise in recent investigations. The purpose of this study, therefore, is to compare the risk of acute periprosthetic joint infection (PJI) in primary TKA patients who received cefazolin and VIP to those who received a non-cephalosporin alternative and VIP. Methods. This was a retrospective cohort study of 11,550 primary TKAs performed at an orthopaedic hospital between 2013 and 2019. The primary outcome was PJI occurring within 90 days of surgery. Patients were stratified into two groups (cefazolin vs non-cephalosporin) based on their preoperative antibiotic. All patients also received the VIP protocol at wound closure. Bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify the odds ratio of PJI. Results. In all, 10,484 knees (90.8%) received cefazolin, while 1,066 knees (9.2%) received a non-cephalosporin agent (either vancomycin or clindamycin) as preoperative prophylaxis. The rate of PJI in the cefazolin group (0.5%; 48/10,484) was significantly lower than the rate of PJI in the non-cephalosporin group (1.0%; 11/1,066) (p = 0.012). After controlling for confounding variables, the odds ratio (OR) of developing a PJI was increased in the non-cephalosporin cohort compared to the cefazolin cohort (OR 2.389; 1.2 to 4.6); p = 0.01). Conclusion. Despite the use of topical irrigant solutions and addition of local antimicrobial agents, the use of a non-cephalosporin perioperative antibiotic continues to be associated with a greater risk of TKA PJI compared to cefazolin. Strategies that increase the proportion of patients receiving cefazolin rather than non-cephalosporin alternatives must be emphasized. Cite this article: Bone Jt Open 2022;3(1):35–41

Aims. There is little published on the outcomes after restarting elective orthopaedic procedures following cessation of surgery due to the COVID-19 pandemic. During the pandemic, the reported perioperative mortality in patients who acquired SARS-CoV-2 infection while undergoing elective orthopaedic surgery was 18% to 20%. The aim of this study is to report the surgical outcomes, complications, and risk of developing COVID-19 in 2,316 consecutive patients who underwent elective orthopaedic surgery in the latter part of 2020 and comparing it to the same, pre-pandemic, period in 2019. Methods. A retrospective service evaluation of patients who underwent elective surgical procedures between 16 June 2020 and 12 December 2020 was undertaken. The number and type of cases, demographic details, American society of Anesthesiologists (ASA) grade, BMI, 30-day readmission rates, mortality, and complications at one- and six-week intervals were obtained and compared with patients who underwent surgery during the same six-month period in 2019. Results. A total of 2,316 patients underwent surgery in 2020 compared to 2,552 in the same period in 2019. There were no statistical differences in sex distribution, BMI, or ASA grade. The 30-day readmission rate and six-week validated complication rates were significantly lower for the 2020 patients compared to those in 2019 (p < 0.05). No deaths were reported at 30 days in the 2020 group as opposed to three in the 2019 group (p < 0.05). In 2020 one patient developed COVID-19 symptoms five days following foot and ankle surgery. This was possibly due to a family contact immediately following discharge from hospital, and the patient subsequently made a full recovery. Conclusion. Elective surgery was safely resumed following the cessation of operating during the COVID-19 pandemic in 2020. Strict adherence to protocols resulted in 2,316 elective surgical procedures being performed with lower complications, readmissions, and mortality compared to 2019. Furthermore, only one patient developed COVID-19 with no evidence that this was a direct result of undergoing surgery. Level of evidence: III. Cite this article: Bone Jt Open 2022;3(1):42–53

Aims. Cementless primary total hip arthroplasty (THA) is associated with risks of bleeding and thromboembolism. Anticoagulants are effective as venous thromboprophylaxis, but with an increased risk of bleeding. Tranexamic acid (TXA) is an efficient antifibrinolytic agent, but the mode and timing of its administration remain controversial. This study aimed to determine whether two intravenous (IV) TXA regimens (a three-hour two-dose (short-TXA) and 11-hour four-dose (long-TXA)) were more effective than placebo in reducing perioperative real blood loss (RBL, between baseline and day 3 postoperatively) in patients undergoing THA who receive rivaroxaban as thromboprophylaxis. The secondary aim was to assess the non-inferiority of the reduction of blood loss of the short protocol versus the long protocol. Patients and Methods. A multicentre, prospective, randomized, double-blind, placebo-controlled trial was undertaken involving 229 patients undergoing primary cementless THA using a posterior approach, whose extended rivaroxaban thromboprophylaxis started on the day of surgery. There were 98 male and 131 female patients, with a mean age of 65.5 years (32 to 91). The primary outcome, perioperative RBL, was evaluated at 72 hours postoperatively. The efficacy of short- and long-TXA protocols in the reduction of perioperative RBL was compared with a placebo group. Results. TXA significantly reduced perioperative blood loss compared with placebo (p < 0.001); the mean differences were 525.3 ml (short-TXA vs placebo) and 550.1 ml (long-TXA vs placebo). No venous or arterial thromboembolic complications were reported. The upper boundary of the 95% confidence interval, when comparing short and long protocols, was below the pre-specified margin of non-inferiority (p = 0.027). Conclusion. In patients undergoing primary cementless THA, using a posterior approach, who are treated with rivaroxaban for thromboembolic prophylaxis, short- and long-TXA IV protocols are significantly more effective than placebo in reducing perioperative RBL, without any thromboembolic complications. Non-inferiority of a short- versus a long-TXA protocol in reducing perioperative RBL was supported in a secondary analysis

Aims. Distraction osteogenesis (DO) is a useful orthopaedic procedure employed to lengthen and reshape bones by stimulating bone formation through controlled slow stretching force. Despite its promising applications, difficulties are still encountered. Our previous study demonstrated that pulsed electromagnetic field (PEMF) treatment significantly enhances bone mineralization and neovascularization, suggesting its potential application. The current study compared a new, high slew rate (HSR) PEMF signal, with different treatment durations, with the standard Food and Drug Administration (FDA)-approved signal, to determine if HSR PEMF is a better alternative for bone formation augmentation. Methods. The effects of a HSR PEMF signal with three daily treatment durations (0.5, one, and three hours/day) were investigated in an established rat DO model with comparison of an FDA-approved classic signal (three hrs/day). PEMF treatments were applied to the rats daily for 35 days, starting from the distraction phase until termination. Radiography, micro-CT (μCT), biomechanical tests, and histological examinations were employed to evaluate the quality of bone formation. Results. All rats tolerated the treatment well and no obvious adverse effects were found. By comparison, the HSR signal (three hrs/day) treatment group achieved the best healing outcome, in that endochondral ossification and bone consolidation were enhanced. In addition, HSR signal treatment (one one hr/day) had similar effects to treatment using the classic signal (three three hrs/day), indicating that treatment duration could be significantly shortened with the HSR signal. Conclusion. HSR signal may significantly enhance bone formation and shorten daily treatment duration in DO, making it a potential candidate for a new clinical protocol for patients undergoing DO treatments. Cite this article: Bone Joint Res 2021;10(12):767–779

Aims. Surgery is often indicated in patients with metastatic bone disease (MBD) to improve pain and maximize function. Few studies are available which report on clinically meaningful outcomes such as quality of life, function, and pain relief after surgery for MBD. This is the published protocol for the Bone Metastasis Audit — Patient Reported Outcomes (BoMA-PRO) multicentre MBD study. The primary objective is to ascertain patient-reported quality of life at three to 24 months post-surgery for MBD. Methods. This will be a prospective, longitudinal study across six UK orthopaedic centres powered to identify the influence of ten patient variables on quality of life at three months after surgery for MBD. Adult patients managed for bone metastases will be screened by their treating consultant and posted out participant materials. If they opt in to participate, they will receive questionnaire packs at regular intervals from three to 24 months post-surgery and their electronic records will be screened until death or five years from recruitment. The primary outcome is quality of life as measured by the European Organisation for Research and the Treatment of Cancer Quality of Life questionnaire (EORTC-QLQ) C30 questionnaire. The protocol has been approved by the Newcastle & North Tyneside 2 Research Ethics Committee (REC ref 19/NE/0303) and the study is funded by the Royal College of Physicians and Surgeons of Glasgow (RCPSG) and the Association for Cancer Surgery (BASO-ACS). Discussion. This will be the first powered study internationally to investigate patient-reported outcomes after orthopaedic treatment for bone metastases. We will assess quality of life, function, and pain relief at three to 24 months post-surgery and identify which patient variables are significantly associated with a good outcome after MBD treatment. Cite this article: Bone Jt Open 2021;2(2):79–85

Aims. While previously underappreciated, factors related to the spine contribute substantially to the risk of dislocation following total hip arthroplasty (THA). These factors must be taken into consideration during preoperative planning for revision THA due to recurrent instability. We developed a protocol to assess the functional position of the spine, the significance of these findings, and how to address different pathologies at the time of revision THA. Patients and Methods. Prospectively collected data on 111 patients undergoing revision THA for recurrent instability from January 2014 to January 2017 at two institutions were included (protocol group) and matched 1:1 to 111 revisions specifically performed for instability not using this protocol (control group). Mean follow-up was 2.8 years. Protocol patients underwent standardized preoperative imaging including supine and standing anteroposterior (AP) pelvis and lateral radiographs. Each case was scored according to the Hip-Spine Classification in Revision THA. Results. Survival free of dislocation at two years was 97% in the protocol group (three dislocations, all within three months of surgery) versus 84% in the control group (18 patients). Furthermore, 77% of the inappropriately positioned acetabular components would have been unrecognized by supine AP pelvis imaging alone. Conclusion. Using the Hip-Spine Classification System in revision THA, we demonstrated a significant decrease in the risk of recurrent instability compared with a control group. Without the use of this algorithm, 77% of inappropriately positioned acetabular components would have been unrecognized and incorrect treatment may have been instituted. Cite this article: Bone Joint J 2019;101-B:817–823

Aims. The aim of this study was to investigate the outcome of periprosthetic fractures of the humerus and to assess the uniformity of the classifications used for these fractures (including those around elbow and/or shoulder arthroplasties) by performing a systematic review of the literature. Methods. A systematic search was conducted using the National Institute for Health and Care Excellence Healthcare Databases Advance Search. For inclusion, studies had to report clinical outcomes following the management of periprosthetic fractures of the humerus. The protocol was registered on the PROSPERO database. Results. Overall, 40 studies were included, involving a total of 210 patients. The fractures were reported using very heterogeneous classification systems, as were the functional outcome scores. A total of 60 patients had nonoperative treatment with a 50% rate of nonunion. Fixation was undertaken in 99 patients; successful union was obtained in 93 (93%). Revision of either the humeral stem or the whole arthroplasty was reported in 79 patients with a high rate of union (n = 66; 84%), and a mean rate of complications of 29% (0% to 41%). Conclusion. This study highlighted a lack of uniformity in classifying these fractures and reporting the outcome of their treatment. The results may help to inform decision-making with patients, particularly about the rate of complications of nonoperative treatment. There is a need to improve the reporting of the pattern of these fractures using a uniform classification system, and the harmonization of the collection of data relating to the outcome of treatment. Based on this review, we propose a minimum dataset to be used in future studies. Cite this article: Bone Joint J 2022;104-B(4):416–423

Aims. As the world continues to fight successive waves of COVID-19 variants, we have seen worldwide infections surpass 100 million. London, UK, has been severely affected throughout the pandemic, and the resulting impact on the NHS has been profound. The aim of this study is to evaluate the impact of COVID-19 on theatre productivity across London’s four major trauma centres (MTCs), and to assess how the changes to normal protocols and working patterns impacted trauma theatre efficiency. Methods. This was a collaborative study across London’s MTCs. A two-month period was selected from 5 March to 5 May 2020. The same two-month period in 2019 was used to provide baseline data for comparison. Demographic information was collected, as well as surgical speciality, procedure, time to surgery, type of anaesthesia, and various time points throughout the patient journey to theatre. Results. In total, 1,243 theatre visits were analyzed as part of the study. Of these, 834 patients presented in 2019 and 409 in 2020. Fewer open reduction and internal fixations were performed in 2020 (33.5% vs 38.2%), and there was an increase in the number of orthoplastic cases in 2020 (8.3% vs 2.2%), both statistically significant results (p < 0.000). There was a statistically significant increase in median time from 2019 to 2020, between sending for a patient and their arrival to the anaesthetic room (29 vs 35 minutes; p = 0.000). Median time between arrival in the anaesthetic room and commencement of anaesthetic increased (7 to 9 minutes; p = 0.104). Conclusion. Changes in working practices necessitated by COVID-19 led to modest delays to all aspects of theatre use, and consequently theatre efficiency. However, the reality is that the major concerns of impact of service did not occur to the levels that were expected. Cite this article: Bone Jt Open 2021;2(10):886–892

Aims. The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively. Methods. A per protocol analysis of 76 patients, 43 of whom underwent TKA and 34 of whom underwent bi-UKA, was performed from a prospective, single-centre, randomized controlled trial. Diaries kept by the patients recorded pain, function, and the use of analgesics daily throughout the first week and weekly between the second and sixth weeks. Patient-reported outcome measures (PROMs) were compared preoperatively, and at three months and one year postoperatively. Data were also compared longitudinally and a subgroup analysis was conducted, stratified by preoperative PROM status. Results. Both operations were shown to offer comparable outcomes, with no significant differences between the groups across all timepoints and outcome measures. Both groups also had similarly low rates of complications. Subgroup analysis for preoperative psychological state, activity levels, and BMI showed no difference in outcomes between the two groups. Conclusion. Robotic arm-assisted, cruciate-sparing bi-UKA offered similar early clinical outcomes and rates of complications to a mechanically aligned TKA, both in the immediate postoperative period and up to one year following surgery. Further work is required to identify which patients with osteoarthritis of the knee will derive benefit from a cruciate-sparing bi-UKA. Cite this article: Bone Joint J 2021;103-B(10):1561–1570

Aims. We studied the impact of direct anterior (DA) versus non-anterior (NA) surgical approaches on prosthetic joint infection (PJI), and examined the impact of new perioperative protocols on PJI rates following all surgical approaches at a single institution. Patients and Methods. A total of 6086 consecutive patients undergoing primary total hip arthroplasty (THA) at a single institution between 2013 and 2016 were retrospectively evaluated. Data obtained from electronic patient medical records included age, sex, body mass index (BMI), medical comorbidities, surgical approach, and presence of deep PJI. There were 3053 male patients (50.1%) and 3033 female patients (49.9%). The mean age and BMI of the entire cohort was 62.7 years (18 to 102, . sd. 12.3) and 28.8 kg/m. 2. (13.3 to 57.6, . sd. 6.1), respectively. Infection rates were calculated yearly for the DA and NA approach groups. Covariates were assessed and used in multivariate analysis to calculate adjusted odds ratios (ORs) for risk of development of PJI with DA compared with NA approaches. In order to determine the effect of adopting a set of infection prevention protocols on PJI, we calculated ORs for PJI comparing patients undergoing THA for two distinct time periods: 2013 to 2014 and 2015 to 2016. These periods corresponded to before and after we implemented a set of perioperative infection protocols. Results. There were 1985 patients in the DA group and 4101 patients in the NA group. The overall rate of PJI at our institution during the study period was 0.82% (50/6086) and decreased from 0.96% (12/1245) in 2013 to 0.53% (10/1870) in 2016. There were 24 deep PJIs in the DA group (1.22%) and 26 deep PJIs in the NA group (0.63%; p = 0.023). After multivariate analysis, the DA approach was 2.2 times more likely to result in PJI than the NA approach (OR 2.2 (95% confidence interval 1.1 to 3.9); p = 0.006) for the overall study period. Conclusion. We found a higher rate of PJI in DA versus NA approaches. Infection prevention protocols such as use of aspirin, dilute povidone-iodine lavage, vancomycin powder, and Gram-negative coverage may have been positively associated with diminished PJI rates observed for all approaches over time. Cite this article: Bone Joint J 2019;101-B(6 Supple B):2–8

Aims. Though the pathogenesis of Legg-Calve-Perthes disease (LCPD) is unknown, repetitive microtrauma resulting in deformity has been postulated. The purpose of this study is to trial a novel upright MRI scanner, to determine whether any deformation occurs in femoral heads affected by LCPD with weightbearing. Methods. Children affected by LCPD were recruited for analysis. Children received both standing weightbearing and supine scans in the MROpen upright MRI scanner, for coronal T1 GFE sequences, both hips in field of view. Parameters of femoral head height, width, and lateral extrusion of affected and unaffected hips were assessed by two independent raters, repeated at a one month interval. Inter- and intraclass correlation coefficients were determined. Standing and supine measurements were compared for each femoral head. Results. Following rigorous protocol development in healthy age-matched volunteers, successful scanning was performed in 11 LCPD-affected hips in nine children, with seven unaffected hips therefore available for comparison. Five hips were in early stage (1 and 2) and six were in late stage (3 and 4). The mean age was 5.3 years. All hips in early-stage LCPD demonstrated dynamic deformity on weightbearing. Femoral head height decreased (mean 1.2 mm, 12.4% decrease), width increased (mean 2.5 mm, 7.2% increase), and lateral extrusion increased (median 2.5 mm, 23% increase) on standing weightbearing MRI compared to supine scans. Negligible deformation was observed in contra-lateral unaffected hips, with less deformation observed in late-stage hips. Inter- and intraclass reliability for all measured parameters was good to excellent. Conclusion. This pilot study has described an effective novel research investigation for children with LCPD. Femoral heads in early-stage LCPD demonstrated dynamic deformity on weightbearing not previously seen, while unaffected hips did not. Expansion of this protocol will allow further translational study into the effects of loading hips with LCPD. Cite this article: Bone Joint Open 2020;1-7:364–369

Aims. The current pandemic caused by COVID-19 is the biggest challenge for national health systems for a century. While most medical resources are allocated to treat COVID-19 patients, several non-COVID-19 medical emergencies still need to be treated, including vertebral fractures and spinal cord compression. The aim of this paper is to report the early experience and an organizational protocol for emergency spinal surgery currently being used in a large metropolitan area by an integrated team of orthopaedic surgeons and neurosurgeons. Methods. An organizational model is presented based on case centralization in hub hospitals and early management of surgical cases to reduce hospital stay. Data from all the patients admitted for emergency spinal surgery from the beginning of the outbreak were prospectively collected and compared to data from patients admitted for the same reason in the same time span in the previous year, and treated by the same integrated team. Results. A total of 19 patients (11 males and eight females, with a mean age of 49.9 years (14 to 83)) were admitted either for vertebral fracture or spinal cord compression in a 19-day period, compared to the ten admitted in the previous year. No COVID-19 patients were treated. The mean time between admission and surgery was 1.7 days, significantly lower than 6.8 days the previous year (p < 0.001). Conclusion. The structural organization and the management protocol we describe allowed us to reduce the time to surgery and ultimately hospital stay, thereby maximizing the already stretched medical resources available. We hope that our early experience can be of value to the medical communities that will soon be in the same emergency situation. Cite this article: Bone Joint J 2020;102-B(6):671–676

Aims. We wanted to evaluate the effects of a bone anabolic agent (bone morphogenetic protein 2 (BMP-2)) on an anti-catabolic background (systemic or local zoledronate) on fixation of allografted revision implants. Methods. An established allografted revision protocol was implemented bilaterally into the stifle joints of 24 canines. At revision surgery, each animal received one BMP-2 (5 µg) functionalized implant, and one raw implant. One group (12 animals) received bone graft impregnated with zoledronate (0.005 mg/ml) before impaction. The other group (12 animals) received untreated bone graft and systemic zoledronate (0.1 mg/kg) ten and 20 days after revision surgery. Animals were observed for an additional four weeks before euthanasia. Results. No difference was detected on mechanical implant fixation (load to failure, stiffness, energy) between local or systemic zoledronate. Addition of BMP-2 had no effect on implant fixation. In the histomorphometric evaluation, implants with local zoledronate had more area of new bone on the implant surface (53%, p = 0.025) and higher volume of allograft (65%, p = 0.007), whereas implants in animals with systemic zoledronate had the highest volume of new bone (34%, p = 0.003). Systemic zoledronate with BMP-2 decreased volume of allograft by 47% (p = 0.017). Conclusion. Local and systemic zoledronate treatment protects bone at different stages of maturity; local zoledronate protects the allograft from resorption and systemic zoledronate protects newly formed bone from resorption. BMP-2 in the dose evaluated with experimental revision implants was not beneficial, since it significantly increased allograft resorption without a significant compensating anabolic effect. Cite this article: Bone Joint Res 2021;10(8):488–497

Aims. The number of convolutional neural networks (CNN) available for fracture detection and classification is rapidly increasing. External validation of a CNN on a temporally separate (separated by time) or geographically separate (separated by location) dataset is crucial to assess generalizability of the CNN before application to clinical practice in other institutions. We aimed to answer the following questions: are current CNNs for fracture recognition externally valid?; which methods are applied for external validation (EV)?; and, what are reported performances of the EV sets compared to the internal validation (IV) sets of these CNNs?. Methods. The PubMed and Embase databases were systematically searched from January 2010 to October 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The type of EV, characteristics of the external dataset, and diagnostic performance characteristics on the IV and EV datasets were collected and compared. Quality assessment was conducted using a seven-item checklist based on a modified Methodologic Index for NOn-Randomized Studies instrument (MINORS). Results. Out of 1,349 studies, 36 reported development of a CNN for fracture detection and/or classification. Of these, only four (11%) reported a form of EV. One study used temporal EV, one conducted both temporal and geographical EV, and two used geographical EV. When comparing the CNN’s performance on the IV set versus the EV set, the following were found: AUCs of 0.967 (IV) versus 0.975 (EV), 0.976 (IV) versus 0.985 to 0.992 (EV), 0.93 to 0.96 (IV) versus 0.80 to 0.89 (EV), and F1-scores of 0.856 to 0.863 (IV) versus 0.757 to 0.840 (EV). Conclusion. The number of externally validated CNNs in orthopaedic trauma for fracture recognition is still scarce. This greatly limits the potential for transfer of these CNNs from the developing institute to another hospital to achieve similar diagnostic performance. We recommend the use of geographical EV and statements such as the Consolidated Standards of Reporting Trials–Artificial Intelligence (CONSORT-AI), the Standard Protocol Items: Recommendations for Interventional Trials–Artificial Intelligence (SPIRIT-AI) and the Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis–Machine Learning (TRIPOD-ML) to critically appraise performance of CNNs and improve methodological rigor, quality of future models, and facilitate eventual implementation in clinical practice. Cite this article: Bone Jt Open 2021;2(10):879–885

Aims. Fungal periprosthetic joint infections (fPJIs) are rare complications, constituting only 1% of all PJIs. Neither a uniform definition for fPJI has been established, nor a standardized treatment regimen. Compared to bacterial PJI, there is little evidence for fPJI in the literature with divergent results. Hence, we implemented a novel treatment algorithm based on three-stage revision arthroplasty, with local and systemic antifungal therapy to optimize treatment for fPJI. Methods. From 2015 to 2018, a total of 18 patients with fPJI were included in a prospective, single-centre study (DKRS-ID 00020409). The diagnosis of PJI is based on the European Bone and Joint Infection Society definition of periprosthetic joint infections. The baseline parameters (age, sex, and BMI) and additional data (previous surgeries, pathogen spectrum, and Charlson Comorbidity Index) were recorded. A therapy protocol with three-stage revision, including a scheduled spacer exchange, was implemented. Systemic antifungal medication was administered throughout the entire treatment period and continued for six months after reimplantation. A minimum follow-up of 24 months was defined. Results. Eradication of infection was achieved in 16 out of 18 patients (88.8%), with a mean follow-up of 35 months (25 to 54). Mixed bacterial and fungal infections were present in seven cases (39%). The interval period, defined as the period of time from explantation to reimplantation, was 119 days (55 to 202). In five patients, a salvage procedure was performed (three cementless modular knee arthrodesis, and two Girdlestone procedures). Conclusion. Therapy for fPJI is complex, with low cure rates according to the literature. No uniform treatment recommendations presently exist for fPJI. Three-stage revision arthroplasty with prolonged systemic antifungal therapy showed promising results. Cite this article: Bone Jt Open 2021;2(8):671–678