Aims. Spinal tuberculosis (TB) remains an important concern. Although spinal TB often has sequelae such as myelopathy after treatment, the predictive factors affecting such unfavourable outcomes are not yet established. We investigated the clinical manifestations and predictors of unfavourable treatment outcomes in patients with spinal TB. Patients and Methods. We performed a multicentre retrospective cohort study of patients with spinal TB. Unfavourable outcome was defined according to previous studies. The prognostic factors for unfavourable outcomes as the primary outcome were determined using multivariable logistic regression analysis and a linear mixed model was used to compare time course of inflammatory markers during treatment. A total of 185 patients were included, of whom 59 patients had unfavourable outcomes. Results. In multivariate regression analysis, the factors associated with unfavourable outcome were old age (odds ratio (OR) 2.51; 95% confidence interval (CI) 1.07 to 5.86; p = 0.034), acid-fast bacilli (AFB) smear positivity in specimens obtained through biopsy (OR 3.05; 95% CI 1.06 to 8.80; p = 0.039), and elevated erythrocyte sedimentation rate (ESR) at the end of treatment (OR 3.85; 95% CI 1.62 to 9.13; p = 0.002). Patients with unfavourable outcomes had a significant trend toward higher ESR during treatment compared with patients with favourable outcome (p = 0.009). Duration of anti-TB and surgical treatment did not affect prognosis. Conclusion. Elevated ESR at the end of treatment could be used as a marker to identify spinal TB patients with a poor prognosis. Patients whose ESR is not normalized during treatment, as well as those with old age and AFB smear positivity, should be aware of unfavourable outcomes. Cite this article: Bone Joint J 2019;101-B:1542–1549

Aims. The main aims were to identify risk factors predictive of a radiolucent line (RLL) around the acetabular component with an interface bioactive bone cement (IBBC) technique in the first year after THA, and evaluate whether these risk factors influence the development of RLLs at five and ten years after THA. Methods. A retrospective review was undertaken of 980 primary cemented THAs in 876 patients using cemented acetabular components with the IBBC technique. The outcome variable was any RLLs that could be observed around the acetabular component at the first year after THA. Univariate analyses with univariate logistic regression and multivariate analyses with exact logistic regression were performed to identify risk factors for any RLLs based on radiological classification of hip osteoarthritis. Results. RLLs were detected in 27.2% of patients one year postoperatively. In multivariate regression analysis controlling for confounders, atrophic osteoarthritis (odds ratio (OR) 2.17 (95% confidence interval (CI), 1.04 to 4.49); p = 0.038) and 26 mm (OR 3.23 (95% CI 1.85 to 5.66); p < 0.001) or 28 mm head diameter (OR 3.64 (95% CI 2.07 to 6.41); p < 0.001) had a significantly greater risk for any RLLs one year after surgery. Structural bone graft (OR 0.19 (95% CI 0.13 to 0.29) p < 0.001) and location of the hip centre within the true acetabular region (OR 0.15 (95% CI 0.09 to 0.24); p < 0.001) were significantly less prognostic. Improvement of the cement-bone interface including complete disappearance and poorly defined RLLs was identified in 15.1% of patients. Kaplan-Meier survival analysis for the acetabular component at ten years with revision of the acetabular component for aseptic loosening as the end point was 100.0% with a RLL and 99.1% without a RLL (95% CI 97.9 to 100). With revision of the acetabular component for any reason as the end point, the survival rate was 99.2% with a RLL (95% CI 97.6 to 100) and 96.5% without a RLL (95% CI 93.4 to 99.7). Conclusion. This study demonstrates that acetabular bone quality, head diameter, structural bone graft, and hip centre position may influence the presence of the any RLL. Cite this article: Bone Joint Open 2021;2(5):278–292

MicroRNAs (miRNAs) are a class of small non-coding RNAs that have emerged as potential predictive, prognostic, and therapeutic biomarkers, relevant to many pathophysiological conditions including limb immobilization, osteoarthritis, sarcopenia, and cachexia. Impaired musculoskeletal homeostasis leads to distinct muscle atrophies. Understanding miRNA involvement in the molecular mechanisms underpinning conditions such as muscle wasting may be critical to developing new strategies to improve patient management. MicroRNAs are powerful post-transcriptional regulators of gene expression in muscle and, importantly, are also detectable in the circulation. MicroRNAs are established modulators of muscle satellite stem cell activation, proliferation, and differentiation, however, there have been limited human studies that investigate miRNAs in muscle wasting. This narrative review summarizes the current knowledge as to the role of miRNAs in the skeletal muscle differentiation and atrophy, synthesizing the findings of published data. Cite this article: Bone Joint Res 2020;9(11):798–807

Aims. Due to widespread cancellations in elective orthopaedic procedures, the number of patients on waiting list for surgery is rising. We aim to determine and quantify if disparities exist between inpatient and day-case orthopaedic waiting list numbers; we also aim to determine if there is a ‘hidden burden’ that already exists due to reductions in elective secondary care referrals. Methods. Retrospective data were collected between 1 April 2020 and 31 December 2020 and compared with the same nine-month period the previous year. Data collected included surgeries performed (day-case vs inpatient), number of patients currently on the orthopaedic waiting list (day-case vs inpatient), and number of new patient referrals from primary care and therapy services. Results. There was a 52.8% reduction in our elective surgical workload in 2020. The majority of surgeries performed in 2020 were day case surgeries (739; 86.6%) with 47.2% of these performed in the independent sector on a ‘lift and shift’ service. The total number of patients on our waiting lists has risen by 30.1% in just 12 months. As we have been restricted in performing inpatient surgery, the inpatient waiting lists have risen by 73.2%, compared to a 1.6% rise in our day-case waiting list. New patient referral from primary care and therapy services have reduced from 3,357 in 2019 to 1,722 in 2020 (49.7% reduction). Conclusion. This study further exposes the increasing number of patients on orthopaedic waiting lists. We observed disparities between inpatient and day-case waiting lists, with dramatic increases in the number of inpatients on the waiting lists. The number of new patient referrals has decreased, and we predict an influx of referrals as the pandemic eases, further adding to the pressure on inpatient waiting lists. Robust planning and allocation of adequate resources is essential to deal with this backlog. Cite this article: Bone Jt Open 2021;2(7):530–534

Aims. This study aimed to determine the minimal detectable change (MDC), minimal clinically important difference (MCID), and substantial clinical benefit (SCB) under distribution- and anchor-based methods for the Mayo Elbow Performance Index (MEPI) and range of movement (ROM) after open elbow arthrolysis (OEA). We also assessed the proportion of patients who achieved MCID and SCB; and identified the factors associated with achieving MCID. Methods. A cohort of 265 patients treated by OEA were included. The MEPI and ROM were evaluated at baseline and at two-year follow-up. Distribution-based MDC was calculated with confidence intervals (CIs) reflecting 80% (MDC 80), 90% (MDC 90), and 95% (MDC 95) certainty, and MCID with changes from baseline to follow-up. Anchor-based MCID (anchored to somewhat satisfied) and SCB (very satisfied) were calculated using a five-level Likert satisfaction scale. Multivariate logistic regression of factors affecting MCID achievement was performed. Results. The MDC increased substantially based on selected CIs (MDC 80, MDC 90, and MDC 95), ranging from 5.0 to 7.6 points for the MEPI, and from 8.2° to 12.5° for ROM. The MCID of the MEPI were 8.3 points under distribution-based and 12.2 points under anchor-based methods; distribution- and anchor-based MCID of ROM were 14.1° and 25.0°. The SCB of the MEPI and ROM were 17.3 points and 43.4°, respectively. The proportion of the patients who attained anchor-based MCID for the MEPI and ROM were 74.0% and 94.7%, respectively; furthermore, 64.2% and 86.8% attained SCB. Non-dominant arm (p = 0.022), higher preoperative MEPI rating (p < 0.001), and postoperative visual analogue scale pain score (p < 0.001) were independent predictors of not achieving MCID for the MEPI, while atraumatic causes (p = 0.040) and higher preoperative ROM (p = 0.005) were independent risk factors for ROM. Conclusion. In patients undergoing OEA, the MCID for the increased MEPI is 12.2 points and 25° increased ROM. The SCB is 17.3 points and 43.3°, respectively. Future studies using the MEPI and ROM to assess OEA outcomes should report not only statistical significance but also clinical importance. Cite this article: Bone Joint J 2021;103-B(2):366–372

Aims. Acetabular fractures in older adults lead to a high risk of mortality and morbidity. However, only limited data have been published documenting functional outcomes in such patients. The aims of this study were to describe outcomes in patients aged 60 years and older with operatively managed acetabular fractures, and to establish predictors of conversion to total hip arthroplasty (THA). Methods. We conducted a retrospective, registry-based study of 80 patients aged 60 years and older with acetabular fractures treated surgically at The Alfred and Royal Melbourne Hospital. We reviewed charts and radiological investigations and performed patient interviews/examinations and functional outcome scoring. Data were provided by the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR). Survival analysis was used to describe conversion to THA in the group of patients who initially underwent open reduction and internal fixation (ORIF). Multivariate regression analyses were performed to identify factors associated with conversion to THA. Results. Seven patients (8.8%) had died at a median follow-up of 18 months (interquartile range (IQR) 12 to 25), of whom four were in the acute THA group. Eight patients (10%) underwent acute THA. Of the patients who underwent ORIF, 17/72 (23.6%) required conversion to THA at a median of 10.5 months (IQR 4.0 to 32.0) . After controlling for other factors, transport-related cases had an 88% lower rate of conversion to THA (hazard ratio (HR) 0.12, 95% confidence interval (CI) 0.02 to 0.91). Mean standardized Physical Component Summary Score (PCS-12) of the 12-Item Short Form Health Survey (SF-12) was comparable with the general population (age-/sex-matched) by 12 to 24 months. Over half of patients working prior to injury (14/26) returned to work by six months and two-thirds of patients (19/27) by 12 months. Conclusion. Patients over 60 years of age managed operatively for displaced acetabular fractures had a relatively high mortality rate and a high conversion rate to THA in the ORIF group but, overall, patients who survived had mean PCS-12 scores that improved over two years and were comparable with controls. Cite this article: Bone Joint J 2020;102-B(12):1735–1742

Aims. We aimed to report the mid- to long-term rates of septic and aseptic failure after two-stage revision surgery for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). Methods. We retrospectively reviewed 96 cases which met the Musculoskeletal Infection Society criteria for PJI. The mean follow-up was 90 months (SD 32). Septic failure was assessed using a Delphi-based consensus definition. Any further surgery undertaken for aseptic mechanical causes was considered as aseptic failure. The cumulative incidence with competing risk analysis was used to predict the risk of septic failure. A regression model was used to evaluate factors associated with septic failure. The cumulative incidence of aseptic failure was also analyzed. Results. There were 23 septic failures at final follow-up, with a cumulative incidence of 14% (95% confidence interval (CI) 8% to 22%) at one year, 18% (95% CI 11% to 27%) at two years, 22% (95% CI 14% to 31%) at five years, and 23% (95% CI 15% to 33%) at ten years. Having at least one positive culture (hazard ratio (HR) 2.38 (interquartile range (IQR) 1.19 to 4.74); p = 0.013), or a positive intraoperative frozen section (HR 2.55 (IQR 1.06 to 6.15); p = 0.037) was significantly associated with septic failure after reimplantation. With dislocation being the most common cause of aseptic revision (5.2%), the cumulative incidence of aseptic failure was 1% (95% CI 0% to 5%) at one year, 6% (95% CI 1% to 8%) at five years, and 8% (95%CI 3% to 17%) at ten years. Conclusion. If there is no recurrent infection in the five years following reimplantation, the chances of further infection thereafter are remote. While the results of a frozen section may be a reliable guide to the timing of reimplantation, intraoperative culture has, currently, only prognostic value. Surgeons should be aware that instability remains a potential indication for further revision surgery. Cite this article: Bone Joint J 2021;103-B(1):79–86

Aims. We aimed to describe the epidemiological, biological, and bacteriological characteristics of osteoarticular infections (OAIs) caused by Kingella kingae. Methods. The medical charts of all children presenting with OAIs to our institution over a 13-year period (January 2007 to December 2019) were reviewed. Among these patients, we extracted those which presented an OAI caused by K. kingae and their epidemiological data, biological results, and bacteriological aetiologies were assessed. Results. K. kingae was the main reported microorganism in our paediatric population, being responsible for 48.7% of OAIs confirmed bacteriologically. K. kingae affects primarily children aged between six months and 48 months. The highest prevalence of OAI caused by K. kingae was between seven months and 24 months old. After the patients were 27 months old, its incidence decreased significantly. The incidence though of infection throughout the year showed no significant differences. Three-quarters of patients with an OAI caused by K. kingae were afebrile at hospital admission, 11% had elevated WBCs, and 61.2% had abnormal CRPs, whereas the ESR was increased in 75%, constituting the most significant predictor of an OAI. On MRI, we noted 53% of arthritis affecting mostly the knee and 31% of osteomyelitis located primarily in the foot. Conclusion. K. kingae should be recognized currently as the primary pathogen causing OAI in children younger than 48 months old. Diagnosis of an OAI caused by K. kingae is not always obvious, since this infection may occur with a mild-to-moderate clinical and biological inflammatory response. Extensive use of nucleic acid amplification assays improved the detection of fastidious pathogens and has increased the observed incidence of OAI, especially in children aged between six months and 48 months. We propose the incorporation of polymerase chain reaction assays into modern diagnostic algorithms for OAIs to better identify the bacteriological aetiology of OAIs. Cite this article: Bone Joint J 2021;103-B(3):578–583

Literature surrounding artificial intelligence (AI)-related applications for hip and knee arthroplasty has proliferated. However, meaningful advances that fundamentally transform the practice and delivery of joint arthroplasty are yet to be realized, despite the broad range of applications as we continue to search for meaningful and appropriate use of AI. AI literature in hip and knee arthroplasty between 2018 and 2021 regarding image-based analyses, value-based care, remote patient monitoring, and augmented reality was reviewed. Concerns surrounding meaningful use and appropriate methodological approaches of AI in joint arthroplasty research are summarized. Of the 233 AI-related orthopaedics articles published, 178 (76%) constituted original research, while the rest consisted of editorials or reviews. A total of 52% of original AI-related research concerns hip and knee arthroplasty (n = 92), and a narrative review is described. Three studies were externally validated. Pitfalls surrounding present-day research include conflating vernacular (“AI/machine learning”), repackaging limited registry data, prematurely releasing internally validated prediction models, appraising model architecture instead of inputted data, withholding code, and evaluating studies using antiquated regression-based guidelines. While AI has been applied to a variety of hip and knee arthroplasty applications with limited clinical impact, the future remains promising if the question is meaningful, the methodology is rigorous and transparent, the data are rich, and the model is externally validated. Simple checkpoints for meaningful AI adoption include ensuring applications focus on: administrative support over clinical evaluation and management; necessity of the advanced model; and the novelty of the question being answered.

Cite this article: Bone Joint J 2022;104-B(12):1292–1303.

Aims. The purpose of this study was to: review the efficacy of the induced membrane technique (IMT), also known as the Masquelet technique; and investigate the relationship between patient factors and technique variations on the outcomes of the IMT. Methods. A systematic search was performed in CINAHL, The Cochrane Library, Embase, Ovid MEDLINE, and PubMed. We included articles from 1 January 1980 to 30 September 2019. Studies with a minimum sample size of five cases, where the IMT was performed primarily in adult patients (≥ 18 years old), in a long bone were included. Multivariate regression models were performed on patient-level data to determine variables associated with nonunion, postoperative infection, and the need for additional procedures. Results. A total of 48 studies were included, with 1,386 cases treated with the IMT. Patients had a mean age of 40.7 years (4 to 88), and the mean defect size was 5.9 cm (0.5 to 26). In total, 82.3% of cases achieved union after the index second stage procedure. The mean time to union was 6.6 months (1.4 to 58.7) after the second stage. Our multivariate analysis of 450 individual patients showed that the odds of developing a nonunion were significantly increased in those with preoperative infection. Patients with tibial defects, and those with larger defects, were at significantly higher odds of developing a postoperative infection. Our analysis also demonstrated a trend towards the inclusion of antibiotics in the cement spacer having a protective effect against the need for additional procedures. Conclusion. The IMT is an effective management strategy for complex segmental bone defects. Standardized reporting of individual patient data or larger prospective trials is required to determine the optimal implementation of this technique. This is the most comprehensive review of the IMT, and the first to compile individual patient data and use regression models to determine predictors of outcomes. Cite this article: Bone Joint J 2020;102-B(12):1723–1734

Aims

Machine-learning (ML) prediction models in orthopaedic trauma hold great promise in assisting clinicians in various tasks, such as personalized risk stratification. However, an overview of current applications and critical appraisal to peer-reviewed guidelines is lacking. The objectives of this study are to 1) provide an overview of current ML prediction models in orthopaedic trauma; 2) evaluate the completeness of reporting following the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement; and 3) assess the risk of bias following the Prediction model Risk Of Bias Assessment Tool (PROBAST) tool.

Aims

To determine the major risk factors for unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) and their interactions, using machine learning-based prediction algorithms and game theory.

Aims. The aim of this study was to explore risk factors for complications associated with dural tear (DT), including the types of DT, and the intra- and postoperative management of DT. Patients and Methods. Between 2012 and 2017, 12 171 patients with degenerative lumbar diseases underwent primary lumbar spine surgery. We investigated five categories of potential predictors: patient factors (sex, age, body mass index, and primary disease), surgical factors (surgical procedures, operative time, and estimated blood loss), types of DT (inaccessible for suturing/clipping and the presence of cauda equina/nerve root herniation), repair techniques (suturing, clipping, fibrin glue, polyethylene glycol (PEG) hydrogel, and polyglycolic acid sheet), and postoperative management (drainage duration). Postoperative complications were evaluated in terms of dural leak, prolonged bed rest, headache, nausea/vomiting, delayed wound healing, postoperative neurological deficit, surgical site infection (SSI), and reoperation for DT. We performed multivariable regression analyses to evaluate the predictors of postoperative complications associated with DT. Results. In total, 429/12 171 patients (3.5%) had a DT. Multivariable analysis revealed that PEG hydrogel significantly reduced the incidence of dural leak and prolonged bed rest, and that patients treated with sealants (fibrin glue and PEG hydrogel) significantly less frequently suffered from headache. A longer drainage duration significantly increased the incidence of headache, nausea/vomiting, and delayed wound healing. Headache and nausea/vomiting were significantly more prevalent in younger female patients. Postoperative neurological deficit and reoperation for DT significantly depended on the presence of cauda equina/nerve root herniation. A longer operative time was the sole independent risk factor for SSI and was also a risk factor for dural leak, prolonged bed rest, and nausea/vomiting. Conclusion. Sealants, particularly PEG hydrogel, may be useful in reducing symptoms related to cerebrospinal fluid leakage, whereas prolonged drainage may be unnecessary. Younger female patients should be carefully treated when DT occurs. Cite this article: Bone Joint J 2019;101-B:1115–1121

Aims. The aim of this study was to determine whether fixation, as opposed to revision arthroplasty, can be safely used to treat reducible Vancouver B type fractures in association with a cemented collarless polished tapered femoral stem (the Exeter). Methods. This retrospective cohort study assessed 152 operatively managed consecutive unilateral Vancouver B fractures involving Exeter stems; 130 were managed with open reduction and internal fixation (ORIF) and 22 with revision arthroplasty. Mean follow-up was 6.5 years (SD 2.6; 3.2 to 12.1). The primary outcome measure was revision of at least one component. Kaplan–Meier survival analysis was performed. Regression analysis was used to identify risk factors for revision following ORIF. Secondary outcomes included any reoperation, complications, blood transfusion, length of hospital stay, and mortality. Results. Fractures (B1 n = 74 (49%); B2 n = 50 (33%); and B3 n = 28 (18%)) occurred at median of 4.2 years (interquartile range (IQR) 1.2 to 9.2) after primary total hip arthroplasty (THA) (n = 138) or hemiarthroplasty (n = 14). Rates of revision and reoperation were significantly higher following revision arthroplasty compared to ORIF for B2 (p = 0.001) and B3 fractures (p = 0.050). Five-year survival was significantly better following ORIF: 92% (95% confidence interval (CI) 86.4% to 97.4%) versus 63% (95% CI 41.7% to 83.3%), p < 0.001. ORIF was associated with reduced blood transfusion requirement and reoperations, but there were no differences in medical complications, hospital stay, or mortality between surgical groups. No independent predictors of revision following ORIF were identified: where the bone-cement interface was intact, fixation of B2 or B3 fractures was not associated with an increased risk of revision. Conclusion. When the bone-cement interface was intact and the fracture was anatomically reducible, all Vancouver B fractures around Exeter stems could be managed with fixation as opposed to revision arthroplasty. Fixation was associated with reduced need for blood transfusion and lower risk of revision surgery compared with revision arthroplasty. Cite this article: Bone Joint J 2021;103-B(2):309–320

The August 2023 Knee Roundup³⁶⁰ looks at: Curettage and cementation of giant cell tumour of bone: is arthritis a given?; Anterior knee pain following total knee arthroplasty: does the patellar cement-bone interface affect postoperative anterior knee pain?; Nickel allergy and total knee arthroplasty; The use of artificial intelligence for the prediction of periprosthetic joint infection following aseptic revision total knee arthroplasty; Ambulatory unicompartmental knee arthroplasty: development of a patient selection tool using machine learning; Femoral asymmetry: a missing piece in knee alignment; Needle arthroscopy – a benefit to patients in the outpatient setting; Can lateral unicompartmental knees be done in a day-case setting?

The December 2023 Hip & Pelvis Roundup³⁶⁰ looks at: Early hip fracture surgery is safe for patients on direct oral anticoagulants; Time to return to work by occupational class after total hip or knee arthroplasty; Is there a consensus on air travel following hip and knee arthroplasty?; Predicting whether patients will achieve minimal clinically important differences following hip or knee arthroplasty; High-dose dual-antibiotic-loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomized controlled trial; Vitamin E – a positive thing in your poly?; Hydroxapatite-coated femoral stems: is there a difference in fixation?

Aims

Glenoid bone loss is a significant problem in the management of shoulder instability. The threshold at which the bone loss is considered “critical” requiring bony reconstruction has steadily dropped and is now approximately 15%. This necessitates accurate measurement in order that the correct operation is performed. CT scanning is the most commonly used modality and there are a number of techniques described to measure the bone loss however few have been validated. The aim of this study was to assess the accuracy of the most commonly used techniques for measuring glenoid bone loss on CT.

Aims

There is a lack of high-quality research investigating outcomes of Ponseti-treated idiopathic clubfeet and correlation with relapse. This study assessed clinical and quality of life (QoL) outcomes using a standardized core outcome set (COS), comparing children with and without relapse.

Aims. In order to determine whether and for whom serial radiological evaluation is necessary in one-part proximal humerus fractures, we set out to describe the clinical history and predictors of secondary displacement in patients sustaining these injuries. Patients and Methods. Between January 2014 and April 2016, all patients with an isolated, nonoperatively treated one-part proximal humerus fracture were prospectively followed up. Clinical and radiological evaluation took place at less than two, six, 12, and 52 weeks. Fracture configuration, bone quality, and comminution were determined on the initial radiographs. Fracture healing, secondary displacement, and treatment changes were recorded during follow-up. Results. In 100 patients (59 female, 41 male; mean age 57 years), 91 of the fractures (91%) remained stable. In five of nine patients (55%) with secondary displacement, surgery was recommended. Comminution, present in 23 patients (23%), was identified as a predictor of secondary displacement (p < 0.001). Patients’ age, sex, fracture configuration, and bone quality were not associated with secondary displacement (p ≥ 0.438). Nonoperative treatment resulted in a mean absolute Constant score (CS) of 80 (49 to 98), relative CS of 101% (63% to 138%), median subjective shoulder value of 95% (interquartile range (IQR) 90% to 100%), and median EuroQol five-dimensional questionnaire score of 0.89 (IQR 0.80 to 1.00) with bone union in all cases at one-year follow-up. Conclusion. Radiological re-evaluation was only necessary in patients presenting with comminution and may be redundant for 77% of patients with one-part proximal humerus fractures. Nonoperative treatment of one-part proximal humerus fractures remains the mainstay of treatment with a low rate of secondary surgery, a high union rate, and good clinical results. Cite this article: Bone Joint J 2019;101-B:1307–1312

Aims

The aims of this study were to: 1) report on a cohort of skeletally mature patients with native hip and knee septic arthritis over a 14-year period; 2) to determine the rate of joint failure in patients who had experienced an episode of hip or knee septic arthritis; and 3) to assess the outcome following septic arthritis relative to the infecting organism, whether those patients infected by Staphylococcus aureus would be more likely to have adverse outcomes than those infected by other organisms.