Aims. This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%). Methods. In a single health centre, patients with suspected PJI were enrolled from January 2013 to December 2021. The inclusion criteria were: 1) patients who were suspected to have PJI; 2) patients with complete medical records; and 3) patients from whom sufficient synovial fluid was obtained for microbial culture and NET test. Patients who received revision surgeries due to aseptic failure (AF) were selected as controls. Synovial fluid was collected for microbial culture and SF-WBC, SF-PNM%, and SF-NET detection. The receiver operating characteristic curve (ROC) of synovial NET, WBC, PMN%, and area under the curve (AUC) were obtained; the diagnostic efficacies of these diagnostic indexes were calculated and compared. Results. The levels of SF-NETs in the PJI group were significantly higher than those of the AF group. The AUC of SF-NET was 0.971 (95% confidence interval (CI) 0.903 to 0.996), the sensitivity was 93.48% (95% CI 82.10% to 98.63%), the specificity was 96.43% (95% CI 81.65% to 99.91%), the accuracy was 94.60% (95% CI 86.73% to 98.50%), the positive predictive value was 97.73%, and the negative predictive value was 90%. Further analysis showed that SF-NET could improve the diagnosis of culture-negative PJI, patients with PJI who received antibiotic treatment preoperatively, and fungal PJI. Conclusion. SF-NET is a novel and ideal synovial fluid biomarker for PJI diagnosis, which could improve PJI diagnosis greatly. Cite this article: Bone Joint Res 2023;12(2):113–120

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

Aims. The aim of this study was to determine the diagnostic utility of histological analysis in spinal biopsies for spondylodiscitis (SD). Patients and Methods. Clinical features, radiology, results of microbiology, histology, and laboratory investigations in 50 suspected SD patients were evaluated. In 29 patients, the final (i.e. treatment-based) diagnosis was pyogenic SD; in seven patients, the final diagnosis was mycobacterial SD. In pyogenic SD, the neutrophil polymorph (NP) infiltrate was scored semi-quantitatively by determining the mean number of NPs per (×400) high-power field (HPF). Results. Of the 29 pyogenic SD patients, 17 had positive microbiology and 21 positive histology (i.e. one or more NPs per HPF on average). All non-SD patients showed less than one NP per HPF. The presence of one or more NPs per HPF had a diagnostic sensitivity of 72.4%, specificity 100%, accuracy 100%, positive predictive value (PPV) 81.0%, and negative predictive value (NPV) 61.9%. Sensitivity, specificity, and accuracy were greater using the criterion of positive histology and/or microbiology than positive histology or microbiology alone. Granulomas were identified histologically in seven mycobacterial SD patients, and positive microbiology was detected in four. Conclusion. The diagnosis of pyogenic SD was more often confirmed by positive histology (one or more NPs per HPF on average) than by microbiology, although diagnostic sensitivity was greater when both histology and microbiology were positive. Cite this article: Bone Joint J 2019;101-B:246–252

Aims. Besides conventional radiographs, the use of MRI, CT, and bone scintigraphy is frequent in the diagnosis of a fracture of the scaphoid. However, which techniques give the best results remain unknown. The investigation of a new imaging technique initially requires an analysis of its precision. The primary aim of this study was to investigate the interobserver agreement of high-resolution peripheral quantitative CT (HR-pQCT) in the diagnosis of a scaphoid fracture. A secondary aim was to investigate the interobserver agreement for the presence of other fractures and for the classification of scaphoid fracture. Methods. Two radiologists and two orthopaedic trauma surgeons evaluated HR-pQCT scans of 31 patients with a clinically-suspected scaphoid fracture. The observers were asked to determine the presence of a scaphoid or other fracture and to classify the scaphoid fracture based on the Herbert classification system. Fleiss kappa statistics were used to calculate the interobserver agreement for the diagnosis of a fracture. Intraclass correlation coefficients (ICCs) were used to assess the agreement for the classification of scaphoid fracture. Results. A total of nine (29%) scaphoid fractures and 12 (39%) other fractures were diagnosed in 20 patients (65%) using HR-pQCT across the four observers. The interobserver agreement was 91% for the identification of a scaphoid fracture (95% confidence interval (CI) 0.76 to 1.00) and 80% for other fractures (95% CI 0.72 to 0.87). The mean ICC for the classification of a scaphoid fracture in the seven patients diagnosed with scaphoid fracture by all four observers was 73% (95% CI 0.42 to 0.94). Conclusion. We conclude that the diagnosis of scaphoid and other fractures is reliable when using HR-pQCT in patients with a clinically-suspected fracture. Cite this article: Bone Joint J 2020;102-B(4):478–484

Aims. This study aimed to explore whether serum combined with synovial interleukin-6 (IL-6) measurement can improve the accuracy of prosthetic joint infection (PJI) diagnosis, and to establish the cut-off values of IL-6 in serum and synovial fluid in detecting chronic PJI. Methods. Patients scheduled to have a revision surgery for indications of chronic infection of knee and hip arthroplasties or aseptic loosening of an implant were prospectively screened before being enrolled into this study. The Musculoskeletal Infection Society (MSIS) definition of PJI was used for the classification of cases as aseptic or infected. Serum CRP, ESR, IL-6, and percentage of polymorphonuclear neutrophils (PMN%) and IL-6 in synovial fluid were analyzed. Statistical tests were performed to compare these biomarkers in the two groups, and receiver operating characteristic (ROC) curves and area under the curve (AUC) were analyzed for each biomarker. Results. A total of 93 patients were enrolled. There was no difference in demographic data between both groups. Synovial fluid IL-6, with a threshold of 1,855.36 pg/ml, demonstrated a mean sensitivity of 94.59% (95% confidence interval (CI) 81.8% to 99.3%) and a mean specificity of 92.86% (95% CI 82.7 to 98.0) for detecting chronic PJI. Then 6.7 pg/ml was determined to be the optimal threshold value of serum IL-6 for the diagnosis of chronic PJI, with a mean sensitivity of 97.30% (95% CI 85.8% to 99.9%) and a mean specificity of 76.79% (95% CI 63.6% to 87.0%). The combination of synovial IL-6 and serum IL-6 led to improved accuracy of 96.77% in diagnosing chronic PJI. Conclusion. The present study identified that a combination of IL-6 in serum and synovial IL-6 has the potential for further improvement of the diagnosis of PJI. Cite this article: Bone Joint Res 2020;9(9):587–592

Aims. This study aimed to investigate the role of quantitative histological analysis in the diagnosis of fracture-related infection (FRI). Patients and Methods. The clinical features, microbiology culture results, and histological analysis in 156 surgically treated nonunions were used to stratify the likelihood of associated infection. There were 64 confirmed infected nonunions (one or more confirmatory criteria: pus, sinus, and bacterial growth in two or more samples), 66 aseptic nonunions (no confirmatory criteria), and 26 possibly infected nonunions (pathogen identified from a single specimen and no confirmatory criteria). The histological inflammatory response was assessed by average neutrophil polymorph (NPs) counts per high-power field (HPF) and compared with the established diagnosis. Results. Assuming a cut-off of over five neutrophils per high-power field to diagnose septic nonunion, there was 80% sensitivity and 100% specificity (accuracy 90%). Using a cut-off of no neutrophils seen in any high-power field to diagnose aseptic nonunion, there was a sensitivity of 85% and a specificity of 98% (accuracy 92%). Conclusion. Histology can be used in a bimodal fashion as a diagnostic test for FRI. The presence of more than five NPs/HPF had a positive predictive value for infected nonunion of 100%, while the complete absence of any NPs is almost always indicative of an aseptic nonunion (positive predictive value of 98%). Cite this article: Bone Joint J 2018;100-B:966–72

Aims. The aim of this study was to evaluate the diagnostic value of preoperative serum CRP, white blood cell count (WBC), percentage of neutrophils (%N), and neutrophil to lymphocyte ratio (NLR) when using the fracture-related infection (FRI) consensus definition. Methods. A cohort of 106 patients having surgery for suspected septic nonunion after failed fracture fixation were studied. Blood samples were collected preoperatively, and the concentration of serum CRP, WBC, and differential cell count were analyzed. The areas under the curve (AUCs) of diagnostic tests were compared using the z-test. Regression trees were constructed and internally cross-validated to derive a simple diagnostic decision tree. Results. Using the FRI consensus definition, 46 patients (43%) were identified as infected. Sensitivity, specificity, and AUC of CRP were 67% (95% confidence interval (CI) 52% to 80%), 61% (95% CI 47% to 74%), and 0.64 (95% CI 0.54 to 0.74); of WBC count were 17% (95% CI 9% to 31%), 95% (95% CI 86% to 99%), and 0.57 (95% CI 0.50 to 0.62); of %N 13% (95% CI 6% to 26%), 87% (95% CI 76% to 93%), and 0.50 (95% CI 0.43 to 0.56); and of NLR 28% (95% CI 17% to 43%), 80% (95% CI 68% to 88%), and 0.54 (95% CI 0.46 to 0.63), respectively. A better performance of serum CRP was shown in comparison to the leucocyte count (p = 0.006), %N (p < 0.001), and NLR (p = 0.001). A statistically lower serum CRP level was shown in patients with an infection caused by a low virulence microorganism in comparison to high virulence bacteria (p = 0.008). We found that a simple decision tree approach using only low serum neutrophils (< 3.615 × 10. 9. /l) and low CRP (< 2.45 mg/l) may allow better identification of aseptic cases. Conclusion. The evaluated serum inflammatory markers showed limited diagnostic value in the preoperative diagnosis of FRI when using the uniform FRI Consensus Definition. Therefore, they should remain as suggestive criteria in diagnosing FRI. Although CRP showed a higher performance in comparison to the other serum markers, it is insufficiently accurate to diagnose a septic nonunion, especially when caused by low virulence microorganisms. Cite this article: Bone Joint J 2020;102-B(7):904–911

Aims. Tuberculosis (TB) infection of bones and joints accounts for 6.7% of TB cases in England, and is associated with significant morbidity and disability. Public Health England reports that patients with TB experience delays in diagnosis and treatment. Our aims were to determine the demographics, presentation and investigation of patients with a TB infection of bones and joints, to help doctors assessing potential cases and to identify avoidable delays. Patients and Methods. This was a retrospective observational study of all adults with positive TB cultures on specimens taken at a tertiary orthopaedic centre between June 2012 and May 2014. A laboratory information system search identified the patients. The demographics, clinical presentation, radiology, histopathology and key clinical dates were obtained from medical records. Results. A total of 31 adult patients were identified. Their median age was 37 years (interquartile range (IQR): 29 to 53); 21 (68%) were male; 89% were migrants. The main sites affected were joints (10, 32%), the spine (8, 26%) and long bones (6, 19%); 8 (26%) had multifocal disease. The most common presenting symptoms were pain (29/31, 94%) and swelling (26/28, 93%). ‘Typical’ symptoms of TB, such as fever, sweats and weight loss, were uncommon. Patients waited a median of seven months (IQR 3 to 13.5) between the onset of symptoms and referral to the tertiary centre and 2.3 months (IQR 1.6 to 3.4.)) between referral and starting treatment. Radiology suggested TB in 26 (84%), but in seven patients (23%) the initial biopsy specimens were not sent for mycobacterial culture, necessitating a second biopsy. Rapid Polymerase Chain Reaction-based testing for TB using Xpert MTB/RIF was performed in five patients; 4 (80%) tested positive for TB. These patients had a reduced time between the diagnostic biopsy and starting treatment than those whose samples were not tested (median eight days versus 36 days, p = 0.016). Conclusion. Patients with bone and joint TB experience delays in diagnosis and treatment, some of which are avoidable. Maintaining a high index of clinical suspicion and sending specimens for mycobacterial culture are crucial to avoid missing cases. Rapid diagnostic tests reduce delays and should be performed on patients with radiological features of TB. Cite this article: Bone Joint J 2018;100-B:119–24

Aims. This study aimed to assess the performance of an automated multiplex polymerase chain reaction (mPCR) technique for rapid diagnosis of native joint septic arthritis. Patients and Methods. Consecutive patients with suspected septic arthritis undergoing aseptic diagnostic joint aspiration were included. The aspirate was used for analysis by mPCR and conventional microbiological analysis. A joint was classed as septic according to modified Newman criteria. Based on receiver operating characteristic (ROC) analysis, the area under the ROC curve (AUC) values of the mPCR and the synovial fluid culture were compared using the z-test. A total of 72 out of 76 consecutive patients (33 women, 39 men; mean age 64 years (22 to 92)) with suspected septic arthritis were included in this study. Results. Of 72 patients, 42 (58%) were deemed to have septic joints. The sensitivity of mPCR and synovial fluid culture was 38% and 29%, respectively. No significant differences were found between the AUCs of both techniques (p = 0.138). A strong concordance of 89% (Cohen’s kappa: 0.65) was shown. The mPCR failed to detect Staphylococcus aureus (n = 1) and Streptococcus pneumoniae (n = 1; no primer included in the mPCR), whereas the synovial fluid culture missed six microorganisms (positive mPCR: S. aureus (n = 2), Cutibacterium acnes (n = 3), coagulase-negative staphylococci (n = 2)). Conclusion. The automated mPCR showed at least a similar performance to the synovial fluid culture (the current benchmark) in diagnosing septic arthritis, having the great advantage of a shorter turnaround time (within five hours). Cite this article: Bone Joint J 2019;101-B:288–296

We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period.

Cite this article: Bone Joint J 2013;95-B:1001–6.

Aims. Multiligament knee injuries (MLKI) are devastating injuries that can result in significant morbidity and time away from sport. There remains considerable variation in strategies employed for investigation, indications for operative intervention, outcome reporting, and rehabilitation following these injuries. At present no study has yet provided a comprehensive overview evaluating the extent, range, and overall summary of the published literature pertaining to MLKI. Our aim is to perform a methodologically rigorous scoping review, mapping the literature evaluating the diagnosis and management of MLKI. Methods. This scoping review will address three aims: firstly, to map the current extent and nature of evidence for diagnosis and management of MLKI; secondly, to summarize and disseminate existing research findings to practitioners; and thirdly, to highlight gaps in current literature. A three-step search strategy as described by accepted methodology will be employed to identify peer-reviewed literature including reviews, technical notes, opinion pieces, and original research. An initial limited search will be performed to determine suitable search terms, followed by an expanded search of four electronic databases (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and Web of Science). Two reviewers will independently screen identified studies for final inclusion. Dissemination. We will map key concepts and evidence, and disseminate existing research findings to the wider orthopaedic and sports medicine community, through both peer-reviewed and non-peer-reviewed literature, and conference and in-person communications. We will highlight gaps in the current literature and determine future priorities for further research. Cite this article: Bone Jt Open 2022;3(11):894–897

Aims. The early diagnosis of cauda equina syndrome (CES) is crucial for a favourable outcome. Several studies have reported the use of an ultrasound scan of the bladder as an adjunct to assess the minimum post-void residual volume of urine (mPVR). However, variable mPVR values have been proposed as a threshold without consensus on a value for predicting CES among patients with relevant symptoms and signs. The aim of this study was to perform a meta-analysis and systematic review of the published evidence to identify a threshold mPVR value which would provide the highest diagnostic accuracy in patients in whom the diagnosis of CES is suspected. Methods. The search strategy used electronic databases (PubMed, Medline, EMBASE, and AMED) for publications between January 1996 and November 2021. All studies that reported mPVR in patients in whom the diagnosis of CES was suspected, followed by MRI, were included. Results. A total of 2,115 studies were retrieved from the search. Seven fulfilled the inclusion criteria. These included 1,083 patients, with data available from 734 being available for meta-analysis. In 125 patients, CES was confirmed by MRI. The threshold value of mPVR reported in each study varied and could be categorized into 100 ml, 200 ml, 300 ml, and 500 ml. From the meta-analysis, 200 ml had the highest diagnostic accuracy, with 82% sensitivity (95% confidence interval (CI) 0.72 to 0.90) and 65% specificity (95% CI 0.70 to 0.90). When compared using summative receiver operating characteristic curves, mPVR of 200 ml was superior to other values in predicting the radiological confirmation of CES. Conclusion. mPVR is a useful tool when assessing patients in whom the diagnosis of CES is suspected. Compared with other values a mPVR of 200 ml had superior sensitivity, specificity, and positive and negative predictive values. In a patient with a suggestive history and clinical findings, a mPVR of > 200 ml should further raise the suspicion of CES. Caution is recommended when considering the mPVR in isolation and using it as an ‘exclusion tool’, and it should only be used as an adjunct to a full clinical assessment. Cite this article: Bone Joint J 2023;105-B(5):487–495

Aims. This Delphi study assessed the challenges of diagnosing soft-tissue knee injuries (STKIs) in acute settings among orthopaedic healthcare stakeholders. Methods. This modified e-Delphi study consisted of three rounds and involved 32 orthopaedic healthcare stakeholders, including physiotherapists, emergency nurse practitioners, sports medicine physicians, radiologists, orthopaedic registrars, and orthopaedic consultants. The perceived importance of diagnostic components relevant to STKIs included patient and external risk factors, clinical signs and symptoms, special clinical tests, and diagnostic imaging methods. Each round required scoring and ranking various items on a ten-point Likert scale. The items were refined as each round progressed. The study produced rankings of perceived importance across the various diagnostic components. Results. In Round 1, the study revealed widespread variability in stakeholder opinions on diagnostic components of STKIs. Round 2 identified patterns in the perceived importance of specific items within each diagnostic component. Round 3 produced rankings of perceived item importance within each diagnostic component. Noteworthy findings include the challenges associated with accurate and readily available diagnostic methods in acute care settings, the consistent acknowledgment of the importance of adopting a patient-centred approach to diagnosis, and the transition from divergent to convergent opinions between Rounds 2 and 3. Conclusion. This study highlights the potential for a paradigm shift in acute STKI diagnosis, where variability in the understanding of STKI diagnostic components may be addressed by establishing a uniform, evidence-based framework for evaluating these injuries. Cite this article: Bone Jt Open 2024;5(11):984–991

Aims. The aim of this study was to evaluate the optimal deep tissue specimen sample number for histopathological analysis in the diagnosis of periprosthetic joint infection (PJI). Methods. In this retrospective diagnostic study, patients undergoing revision surgery after total hip or knee arthroplasty (n = 119) between January 2015 and July 2018 were included. Multiple specimens of the periprosthetic membrane and pseudocapsule were obtained for histopathological analysis at revision arthroplasty. Based on the Infectious Diseases Society of America (IDSA) 2013 criteria, the International Consensus Meeting (ICM) 2018 criteria, and the European Bone and Joint Infection Society (EBJIS) 2021 criteria, PJI was defined. Using a mixed effects logistic regression model, the sensitivity and specificity of the histological diagnosis were calculated. The optimal number of periprosthetic tissue specimens for histopathological analysis was determined by applying the Youden index. Results. Based on the EBJIS criteria (excluding histology), 46 (39%) patients were classified as infected. Four to six specimens showed the highest Youden index (four specimens: 0.631; five: 0.634; six: 0.632). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of five tissue specimens were 76.5% (95% confidence interval (CI) 67.6 to 81.4), 86.8% (95% CI 81.3 to 93.5), 66.0% (95% CI 53.2 to 78.7), and 84.3% (95% CI 79.4 to 89.3), respectively. The area under the curve (AUC) was calculated with 0.81 (as a function of the number of tissue specimens). Applying the ICM and IDSA criteria (excluding histology), 40 (34%) and 32 (27%) patients were categorized as septic. Three to five specimens had the highest Youden index (ICM 3: 0.648; 4: 0.651; 5: 0.649) (IDSA 3: 0.627; 4: 0.629; 5: 0.625). Conclusion. Three to six tissue specimens of the periprosthetic membrane and pseudocapsule should be collected at revision arthroplasty and analyzed by a pathologist experienced and skilled in interpreting periprosthetic tissue. Cite this article: Bone Joint J 2023;105-B(2):158–165

Aims. Only a few studies have investigated the long-term health-related quality of life (HRQoL) in patients with an idiopathic scoliosis. The aim of this study was to investigate the overall HRQoL and employment status of patients with an idiopathic scoliosis 40 years after diagnosis, to compare it with that of the normal population, and to identify possible predictors for a better long-term HRQoL. Methods. We reviewed the full medical records and radiological reports of patients referred to our hospital with a scoliosis of childhood between April 1972 and April 1982. Of 129 eligible patients with a juvenile or adolescent idiopathic scoliosis, 91 took part in the study (71%). They were evaluated with full-spine radiographs and HRQoL questionnaires and compared with normative data. We compared the HRQoL between observation (n = 27), bracing (n = 46), and surgical treatment (n = 18), and between thoracic and thoracolumbar/lumbar (TL/L) curves. Results. The mean time to follow-up was 40.8 years (SD 2.6) and the mean age of patients was 54.0 years (SD 2.7). Of the 91 patients, 86 were female (95%) and 51 had a main thoracic curve (53%). We found a significantly lower HRQoL measured on all the Scoliosis Research Society 22r instrument (SRS-22r) subdomains (p < 0.001) with the exception of mental health, than in an age-matched normal population. Incapacity to work was more prevalent in scoliosis patients (21%) than in the normal population (11%). The median SRS-22r subscore was 4.0 (interquartile range (IQR) 3.3 to 4.4) for TL/L curves and 4.1 (IQR 3.8 to 4.4) for thoracic curves (p = 0.300). We found a significantly lower self-image score for braced (median 3.6 (IQR 3.0 to 4.0)) and surgically treated patients (median 3.6 (IQR 3.2 to 4.3)) than for those treated by observation (median 4.0 (IQR 4.1 to 4.8); p = 0.010), but no statistically significant differences were found for the remaining subdomains. Conclusion. In this long-term follow-up study, we found a significantly decreased HRQoL and capacity to work in patients with an idiopathic scoliosis 40 years after diagnosis. Cite this article: Bone Joint J 2023;105-B(2):166–171

Aims. The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach. Methods. A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered to be unanimous. Results. Of 27 questions and statements on patellar instability, three achieved unanimous consensus, 14 achieved strong consensus, five achieved consensus, and five did not achieve consensus. Conclusion. The statements that reached unanimous consensus were that an assessment of physeal status is critical for paediatric patients with patellar instability. There was also unanimous consensus on early mobilization and resistance training following nonoperative management once there is no apprehension. The statements that did not achieve consensus were on the importance of immobilization of the knee, the use of orthobiologics in nonoperative management, the indications for MPFC repair, and whether a vastus medialis oblique advancement should be performed. Cite this article: Bone Joint J 2023;105-B(12):1259–1264

Aims. This study evaluated the definitions developed by the European Bone and Joint Infection Society (EBJIS) 2021, the International Consensus Meeting (ICM) 2018, and the Infectious Diseases Society of America (IDSA) 2013, for the diagnosis of periprosthetic joint infection (PJI). Methods. In this single-centre, retrospective analysis of prospectively collected data, patients with an indicated revision surgery after a total hip or knee arthroplasty were included between 2015 and 2020. A standardized diagnostic workup was performed, identifying the components of the EBJIS, ICM, and IDSA criteria in each patient. Results. Of 206 included patients, 101 (49%) were diagnosed with PJI with the EBJIS definition. IDSA and ICM diagnosed 99 (48%) and 86 (42%) as infected, respectively. A total of 84 cases (41%) had an infection based on all three criteria. In 15 cases (n = 15/206; 7%), PJI was present when applying only the IDSA and EBJIS criteria. No infection was detected by one definition alone. Inconclusive diagnoses occurred more frequently with the ICM criteria (n = 30/206; 15%) compared to EBJIS (likely infections: n = 16/206; 8%) (p = 0.029). A better preoperative performance of the EBJIS definition was seen compared with the ICM and IDSA definitions (p < 0.001). Conclusion. The novel EBJIS definition identified all PJIs diagnosed by any other criteria. Use of the EBJIS definition significantly reduced the number of uncertain diagnoses, allowing easier clinical decision-making. Cite this article: Bone Joint Res 2022;11(9):608–618

Aims. Use of molecular sequencing methods in periprosthetic joint infection (PJI) diagnosis and organism identification have gained popularity. Next-generation sequencing (NGS) is a potentially powerful tool that is now commercially available. The purpose of this study was to compare the diagnostic accuracy of NGS, polymerase chain reaction (PCR), conventional culture, the Musculoskeletal Infection Society (MSIS) criteria, and the recently proposed criteria by Parvizi et al in the diagnosis of PJI. Methods. In this retrospective study, aspirates or tissue samples were collected in 30 revision and 86 primary arthroplasties for routine diagnostic investigation for PJI and sent to the laboratory for NGS and PCR. Concordance along with statistical differences between diagnostic studies were calculated. Results. Using the MSIS criteria to diagnose PJI as the reference standard, the sensitivity and specificity of NGS were 60.9% and 89.9%, respectively, while culture resulted in sensitivity of 76.9% and specificity of 95.3%. PCR had a low sensitivity of 18.4%. There was no significant difference based on sample collection method (tissue swab or synovial fluid) (p = 0.760). There were 11 samples that were culture-positive and NGS-negative, of which eight met MSIS criteria for diagnosing infection. Conclusion. In our series, NGS did not provide superior sensitivity or specificity results compared to culture. PCR has little utility as a standalone test for PJI diagnosis with a sensitivity of only 18.4%. Currently, several laboratory tests for PJI diagnosis should be obtained along with the overall clinical picture to help guide decision-making for PJI treatment. Cite this article: Bone Joint J 2021;103-B(1):26–31

Aims. The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid. Methods. Between October 2017 and September 2019, we collected synovial fluid samples from patients scheduled to undergo revision surgery for painful total knee arthroplasty (TKA). The International Consensus Meeting criteria were used to classify 33 PJIs and 92 aseptic joints. LC-MS assay was performed to measure alpha-defensin in synovial fluid of all included patients. Sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristic curve (AUC) were calculated to define the test diagnostic accuracy. Results. The AUC was 0.99 (95% confidence interval (CI) 0.98 to 1.00). Receiver operating characteristic (ROC) analysis showed that the optimal cut-off value of synovial fluid alpha-defensin was 1.0 μg/l. The sensitivity of alpha-defensin was 100% (95% CI 96 to 100), the specificity was 97% (95% CI 90 to 98), the positive predictive value was 89.2% (95% CI 82 to 94), and negative predictive value was 100% (95% CI 96 to 100). ROC analysis demonstrated an AUC of 0.99 (95% CI 0.98 to 1.0). Conclusion. The present study confirms the utility of alpha-defensin in the synovial fluid in patients with painful TKA to select cases of PJI. Since LC-MS is still a time-consuming technology and is available in highly specialized laboratories, further translational research studies are needed to take this evidence into routine procedures and promote a new diagnostic approach. Cite this article: Bone Joint J 2022;104-B(9):1047–1051

Aims. The preoperative diagnosis of periprosthetic joint infection (PJI) remains a challenge due to a lack of biomarkers that are both sensitive and specific. We investigated the performance characteristics of polymerase chain reaction (PCR), interleukin-6 (IL6), and calprotectin of synovial fluid in the diagnosis of PJI. Methods. We performed systematic search of PubMed, Embase, The Cochrane Library, Web of Science, and Science Direct from the date of inception of each database through to 31 May 2021. Studies which described the diagnostic accuracy of synovial fluid PCR, IL6, and calprotectin using the Musculoskeletal Infection Society criteria as the reference standard were identified. Results. Overall, 31 studies were identified: 20 described PCR, six described IL6, and five calprotectin. The sensitivity and specificity were 0.78 (95% confidence interval (CI) 0.67 to 0.86) and 0.97 (95% CI 0.94 to 0.99), respectively, for synovial PCR;, 0.86 (95% CI 0.74 to 0.92), and 0.94 (95% CI 0.90 to 0.96), respectively, for synovial IL6; and 0.94 (95% CI 0.82 to 0.98) and 0.93 (95% CI 0.85 to 0.97), respectively, for synovial calprotectin. Likelihood ratio scattergram analyses recommended clinical utility of synovial fluid PCR and IL6 as a confirmatory test only. Synovial calprotectin had utility in the exclusion and confirmation of PJI. Conclusion. Synovial fluid PCR and IL6 had low sensitivity and high specificity in the diagnosis of PJI, and is recommended to be used as confirmatory test. In contrast, synovial fluid calprotectin had both high sensitivity and specificity with utility in both the exclusion and confirmation of PJI. We recommend use of synovial fluid calprotectin studies in the preoperative workup of PJI. Cite this article: Bone Joint J 2022;104-B(3):311–320

Aims. The aim of this study was to assess the prognostic value of the modified three-group Stulberg classification, which is based on the sphericity of the femoral head, in patients with Perthes’ disease. Methods. A total of 88 patients were followed from the time of diagnosis until a mean follow-up of 21 years. Anteroposterior pelvic and frog-leg lateral radiographs were obtained at diagnosis and at follow-up of one, five, and 21 years. At the five- and 21-year follow-up, the femoral heads were classified using a modified three-group Stulberg classification (round, ovoid, or flat femoral head). Further radiological endpoints at long-term follow-up were osteoarthritis (OA) of the hip and the requirement for total hip arthroplasty (THA). Results. There were 71 males (81%) and 17 females. A total of 13 patients had bilateral Perthes’ disease; thus 101 hips were analyzed. At five-year follow-up, 37 hips were round, 38 ovoid, and 26 flat. At that time, 66 hips (65%) were healed and 91 (90%) were skeletally immature. At long-term follow-up, when the mean age of the patients was 28 years (24 to 34), 20 hips had an unsatisfactory outcome (seven had OA and 13 had required THA). There was a strongly significant association between the modified Stulberg classification applied atfive-year follow-up and an unsatisfactory outcome at long-term follow-up (p < 0.001). Between the five- and 21-year follow-up, 67 hips (76%) stayed in their respective modified Stulberg group, indicating a strongly significant association between the Stulberg classifications at these follow-ups (p < 0.001). Conclusion. The modified Stulberg classification is a strong predictor of long-term radiological outcome in patients with Perthes’ disease. It can be applied at the healing stage, which is usually reached five years after the diagnosis is made and before skeletal maturity. Cite this article: Bone Joint J 2021;103-B(12):1815–1820

Aims. The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition. Methods. This paper reports the outcome of a project developed by the European Bone and Joint Infection Society (EBJIS), and supported by the Musculoskeletal Infection Society (MSIS) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Implant-Associated Infections (ESGIAI). It comprised a comprehensive review of the literature, open discussion with Society members and conference delegates, and an expert panel assessment of the results to produce the final guidance. Results. This process evolved a three-level approach to the diagnostic continuum, resulting in a definition set and guidance, which has been fully endorsed by EBJIS, MSIS, and ESGIAI. Conclusion. The definition presents a novel three-level approach to diagnosis, based on the most robust evidence, which will be useful to clinicians in daily practice. Cite this article: Bone Joint J 2021;103-B(1):18–25

Aims. The diagnosis of developmental dysplasia of the hip (DDH) is challenging owing to extensive variation in paediatric pelvic anatomy. Artificial intelligence (AI) may represent an effective diagnostic tool for DDH. Here, we aimed to develop an anteroposterior pelvic radiograph deep learning system for diagnosing DDH in children and analyze the feasibility of its application. Methods. In total, 10,219 anteroposterior pelvic radiographs were retrospectively collected from April 2014 to December 2018. Clinicians labelled each radiograph using a uniform standard method. Radiographs were grouped according to age and into ‘dislocation’ (dislocation and subluxation) and ‘non-dislocation’ (normal cases and those with dysplasia of the acetabulum) groups based on clinical diagnosis. The deep learning system was trained and optimized using 9,081 radiographs; 1,138 test radiographs were then used to compare the diagnoses made by deep learning system and clinicians. The accuracy of the deep learning system was determined using a receiver operating characteristic curve, and the consistency of acetabular index measurements was evaluated using Bland-Altman plots. Results. In all, 1,138 patients (242 males; 896 females; mean age 1.5 years (SD 1.79; 0 to 10) were included in this study. The area under the receiver operating characteristic curve, sensitivity, and specificity of the deep learning system for diagnosing hip dislocation were 0.975, 276/289 (95.5%), and 1,978/1,987 (99.5%), respectively. Compared with clinical diagnoses, the Bland-Altman 95% limits of agreement for acetabular index, as determined by the deep learning system from the radiographs of non-dislocated and dislocated hips, were -3.27° - 2.94° and -7.36° - 5.36°, respectively (p < 0.001). Conclusion. The deep learning system was highly consistent, more convenient, and more effective for diagnosing DDH compared with clinician-led diagnoses. Deep learning systems should be considered for analysis of anteroposterior pelvic radiographs when diagnosing DDH. The deep learning system will improve the current artificially complicated screening referral process. Cite this article: Bone Joint J 2020;102-B(11):1574–1581

Aims. Perthes’ disease is a condition which leads to necrosis of the femoral head. It is most commonly reported in children aged four to nine years, with recent statistics suggesting it affects around five per 100,000 children in the UK. Current treatment for the condition aims to maintain the best possible environment for the disease process to run its natural course. Management typically includes physiotherapy with or without surgical intervention. Physiotherapy intervention often will include strengthening/stretching programmes, exercise/activity advice, and, in some centres, will include intervention, such as hydrotherapy. There is significant variation in care with no consensus on which treatment option is best. The importance of work in this area has been demonstrated by the British Society for Children’s Orthopaedic Surgery through the James Lind Alliance’s prioritization of work to determine/identify surgical versus non-surgical management of Perthes’ disease. It was identified as the fourth-highest priority for paediatric lower limb surgery research in 2018. Methods. Five UK NHS centres, including those from the NEWS (North, East, West and South Yorkshire) orthopaedic group, contributed to this case review, with each entre providing clinical data from a minimum of five children. Information regarding both orthopaedic and physiotherapeutic management over a two-year post-diagnosis period was reviewed. Results. Data were extracted from the clinical records of 32 children diagnosed with Perthes’ disease; seven boys and 25 girls. The mean age of the children at diagnosis was 6.16 years (standard deviation (SD) 3.001). In all, 26 children were referred for physiotherapy. In the two-year period following diagnosis, children were seen a median of 7.5 times (interquartile range (IQR) 4.25 to 11) by an orthopaedic surgeon, and a median of 9.5 times (IQR 8 to 18.25) by a physiotherapist. One centre had operated on all of their children, while another had operated on none. Overall, 17 (53%) of the children were managed conservatively in the two-year follow-up period, and 15 (47%) of the children underwent surgery in the two-year follow-up period. Conclusion. The results of this case review demonstrate a variation of care provided to children in the UK with Perthes’ disease. Further national and international understanding of current care is required to underpin the rationale for different treatment options in children with Perthes’ disease. Cite this article: Bone Joint Open 2020;1-11:691–695

Objectives. Prosthetic joint infection (PJI) diagnosis is a major challenge in orthopaedics, and no reliable parameters have been established for accurate, preoperative predictions in the differential diagnosis of aseptic loosening or PJI. This study surveyed factors in synovial fluid (SF) for improving PJI diagnosis. Methods. We enrolled 48 patients (including 39 PJI and nine aseptic loosening cases) who required knee/hip revision surgery between January 2016 and December 2017. The PJI diagnosis was established according to the Musculoskeletal Infection Society (MSIS) criteria. SF was used to survey factors by protein array and enzyme-linked immunosorbent assay to compare protein expression patterns in SF among three groups (aseptic loosening and first- and second-stage surgery). We compared routine clinical test data, such as C-reactive protein level and leucocyte number, with potential biomarker data to assess the diagnostic ability for PJI within the same patient groups. Results. Cut-off values of 1473 pg/ml, 359 pg/ml, and 8.45 pg/ml were established for interleukin (IL)-16, IL-18, and cysteine-rich with EGF-like domains 2 (CRELD2), respectively. Receiver operating characteristic curve analysis showed that these factors exhibited an accuracy of 1 as predictors of PJI. These factors represent potential biomarkers for decisions associated with prosthesis reimplantation based on their ability to return to baseline values following the completion of debridement. Conclusion. IL-16, IL-18, and CRELD2 were found to be potential biomarkers for PJI diagnosis, with SF tests outperforming blood tests in accuracy. These factors could be useful for assessing successful debridement based on their ability to return to baseline values following the completion of debridement. Cite this article: M-F. Chen, C-H. Chang, L-Y. Yang, P-H. Hsieh, H-N. Shih, S. W. N. Ueng, Y. Chang. Synovial fluid interleukin-16, interleukin-18, and CRELD2 as novel biomarkers of prosthetic joint infections. Bone Joint Res 2019;8:179–188. DOI: 10.1302/2046-3758.84.BJR-2018-0291.R1

Aims. As a proven and comprehensive molecular technique, metagenomic next-generation sequencing (mNGS) has shown its potential in the diagnosis of pathogens in patients with periprosthetic joint infection (PJI), using a single type of specimen. However, the optimal use of mNGS in the management of PJI has not been explored. In this study, we evaluated the diagnostic value of mNGS using three types of specimen with the aim of achieving a better choice of specimen for mNGS in these patients. Methods. In this prospective study, 177 specimens were collected from 59 revision arthroplasties, including periprosthetic tissues, synovial fluid, and prosthetic sonicate fluid. Each specimen was divided into two, one for mNGS and one for culture. The criteria of the Musculoskeletal Infection Society were used to define PJI (40 cases) and aseptic failure (19 cases). Results. The sensitivity and specificity of mNGS in the diagnosis of PJI were 95% and 94.7%, respectively, for all types of specimen. The sensitivity and specificity were 65% and 100%, respectively, for periprosthetic tissues, 87.5% and 94.7%, respectively, for synovial fluid, and 92.5% and 94.7%, respectively, for prosthetic sonicate fluid. The mNGS of prosthetic sonicate fluid outperformed that for other types of specimen in the rates of detection of pathogens (84.6%), sequencing reads (> ten-fold) and the rate of genome coverage (> five-fold). Conclusion. mNGS could serve as an accurate diagnostic tool in the detection of pathogens in patients with a PJI using three types of specimen. Due to its superior perfomance in identifying a pathogen, mNGS of prosthetic sonicate fluid provides the most value and may partly replace traditional tests such as bacteriological culture in these patients. Cite this article: Bone Joint J 2021;103-B(5):923–930

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This study aimed to evaluate rasterstereography of the spine as a diagnostic test for adolescent idiopathic soliosis (AIS), and to compare its results with those obtained using a scoliometer.

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We investigated the prevalence of late developmental dysplasia of the hip (DDH), abduction bracing treatment, and surgical procedures performed following the implementation of universal ultrasound screening versus selective ultrasound screening programmes.

Aims. The aim of this study was to compare the results of 16S/28S rRNA sequencing with the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and synovial fluid analysis in the diagnosis of prosthetic joint infection (PJI). Patients and Methods. Between September 2015 and August 2016, 214 consecutive patients were enrolled. In the study population, there were 25 patients with a PJI and 189 controls. Of the PJI patients, 14 (56%) were women, and the mean age at the time of diagnosis was 65 years (38 to 83). The ESR and CRP levels were measured, and synovial fluid specimens were collected prospectively. Synovial fluid was subjected to reverse transcription polymerase chain reaction (RT-PCR)/sequence analysis targeting the 16S/28S rRNA, and to conventional culture. Laboratory personnel who were blind to the clinical information performed all tests. The diagnosis of PJI was based on the criteria of the Musculoskeletal Infection Society. Results. A total of 25 patients had a confirmed PJI. In 20 cases of monomicrobial PJI, the PCR products could be perfectly matched with the 16S/28S rRNA genes specific for different species of bacteria provided by sequence analysis. Of the five polymicrobial cases of PJI, 16S/28S rRNA PCR sequence analysis failed to identify the concordant bacteria species. In the 189 control patients, there was one false-positive RT-PCR result. The sensitivity and specificity of the molecular diagnosis method were 100% (95% confidence interval (CI) 85.7 to 100) and 99.5% (95% CI 97.1 to 99.9), respectively, whereas the positive and negative predictive values of PCR were 96.1% (95% CI 79.6 to 99.9) and 100% (95% CI 98.1 to 100), respectively. The PCR results were significantly better than serological diagnostic methods (p = 0.004 and p = 0.010 for ESR and CRP, respectively), the synovial fluid white blood cell (WBC) count (p = 0.036), and percentage of polymorphonuclear cells (PMN%) (p = 0.014). Conclusion. Stepwise RT-PCR and sequence analysis of the 16S/28S rRNA carried out under stringent laboratory conditions achieved highly sensitive and specific results for the differentiation between aseptic and septic joints undergoing arthroplasty. Sequence analysis successfully identified bacterial strains in monomicrobial infections but failed to identify molecular targets in polymicrobial infections. Further refinement of the protocols to identify the bacteria in polymicrobial infections is needed. Cite this article: Bone Joint J 2018;100-B:1345–51

Aims. The aim of this study was to further evaluate the accuracy of ten promising synovial biomarkers (bactericidal/permeability-increasing protein (BPI), lactoferrin (LTF), neutrophil gelatinase-associated lipocalin (NGAL), neutrophil elastase 2 (ELA-2), α-defensin, cathelicidin LL-37 (LL-37), human β-defensin (HBD-2), human β-defensin 3 (HBD-3), D-dimer, and procalcitonin (PCT)) for the diagnosis of periprosthetic joint infection (PJI), and to investigate whether inflammatory joint disease (IJD) activity affects their concentration in synovial fluid. Methods. We included 50 synovial fluid samples from patients with (n = 25) and without (n = 25) confirmed PJI from an institutional tissue bank collected between May 2015 and December 2016. We also included 22 synovial fluid samples aspirated from patients with active IJD presenting to Department of Rheumatology, the first Medical Centre, Chinese PLA General Hospital. Concentrations of the ten candidate biomarkers were measured in the synovial fluid samples using standard enzyme-linked immunosorbent assays (ELISA). The diagnostic accuracy was evaluated by receiver operating characteristic (ROC) curves. Results. BPI, LTF, NGAL, ELA-2, and α-defensin were well-performing biomarkers for detecting PJI, with areas under the curve (AUCs) of 1.000 (95% confidence interval, 1.000 to 1.000), 1.000 (1.000 to 1.000), 1.000 (1.000 to 1.000), 1.000 (1.000 to 1.000), and 0.998 (0.994 to 1.000), respectively. The other markers (LL-37, HBD-2, D-dimer, PCT, and HBD-3) had limited diagnostic value. For the five well-performing biomarkers, elevated concentrations were observed in patients with active IJD. The original best thresholds determined by the Youden index, which discriminated PJI cases from non-PJI cases could not discriminate PJI cases from active IJD cases, while elevated thresholds resulted in good performance. Conclusion. BPI, LTF, NGAL, ELA-2, and α-defensin demonstrated excellent performance for diagnosing PJI. However, all five markers showed elevated concentrations in patients with IJD activity. For patients with IJD, elevated thresholds should be considered to accurately diagnose PJI. Cite this article: Bone Joint J 2021;103-B(1):32–38

Aims. Leucocyte esterase (LE) has been shown to be an accurate marker of prosthetic joint infection (PJI), and has been proposed as an alternative to frozen section (FS) histology for intraoperative diagnosis. In this study, the intraoperative assessment of LE was compared with FS histology for the diagnosis of prosthetic hip infection. Patients and Methods. A total of 119 patients undergoing revision total hip arthroplasty (THA) between June 2015 and December 2017 were included in the study. There were 56 men and 63 women with a mean age of 66.2 years (27 to 88). Synovial fluid was collected before arthrotomy for the assessment of LE using enzymatic colourimetric strips. Between five and six samples were stained with haematoxylin and eosin for FS histology, and considered suggestive of infection when at least five polymorphonuclear leucocytes were found in five high-power fields. Results. The sensitivity and specificity of the LE assay were 100% and 93.8%, respectively; the positive (PPV) and the negative (NPV) predictive values were 79.3% and 100%, respectively. The mean time between the collection of the sample and the result being known was 20.1 minutes (. sd. 4.4). The sensitivity and specificity of FS histology were 78.3% and 96.9%, respectively; the PPV and the NPV were 85.7% and 94.9%, respectively. The mean time between the collection of the sample and the result being known was 27.2 minutes (. sd. 6.9). Conclusion. The sensitivity of LE assay was higher, with similar specificity and diagnostic accuracy, compared with FS histology. The faster turnaround time, its ease of use, and low costs make LE assay a valuable alternative to FS histology. We now use it routinely for the intraoperative diagnosis of PJI. Cite this article: Bone Joint J 2019;101-B:372–377

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The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

Neuropathic changes in the foot are common with a prevalence of approximately 1%. The diagnosis of neuropathic arthropathy is often delayed in diabetic patients with harmful consequences including amputation. The appropriate diagnosis and treatment can avoid an extensive programme of treatment with significant morbidity for the patient, high costs and delayed surgery. The pathogenesis of a Charcot foot involves repetitive micro-trauma in a foot with impaired sensation and neurovascular changes caused by pathological innervation of the blood vessels. In most cases, changes are due to a combination of both pathophysiological factors. The Charcot foot is triggered by a combination of mechanical, vascular and biological factors which can lead to late diagnosis and incorrect treatment and eventually to destruction of the foot. This review aims to raise awareness of the diagnosis of the Charcot foot (diabetic neuropathic osteoarthropathy and the differential diagnosis, erysipelas, peripheral arterial occlusive disease) and describe the ways in which the diagnosis may be made. The clinical diagnostic pathways based on different classifications are presented. Cite this article: Bone Joint J 2016;98-B:1155–9

Aims. Metagenomic next-generation sequencing (mNGS) is useful in the diagnosis of infectious disease. However, while it is highly sensitive at identifying bacteria, it does not provide information on the sensitivity of the organisms to antibiotics. The purpose of this study was to determine whether the results of mNGS can be used to guide optimization of culture methods to improve the sensitivity of culture from intraoperative samples. Methods. Between July 2014 and October 2019, patients with suspected joint infection (JI) from whom synovial fluid (SF) was obtained preoperatively were enrolled. Preoperative aspirated SF was analyzed by conventional microbial culture and mNGS. In addition to samples taken for conventional microbial culture, some samples were taken for intraoperative culture to optimize the culture method according to the preoperative mNGS results. The demographic characteristics, medical history, laboratory examination, mNGS, and culture results of the patients were recorded, and the possibility of the optimized culture methods improving diagnostic efficiency was evaluated. Results. A total of 56 cases were included in this study. There were 35 cases of JI and 21 cases of non-joint infection (NJI). The sensitivity, specificity, and accuracy of intraoperative microbial culture after optimization of the culture method were 94.29%, 76.19%, and 87.5%, respectively, while those of the conventional microbial culture method were 60%, 80.95%, and 67.86%, respectively. Conclusion. Preoperative aspirated SF detected via mNGS can provide more aetiological information than preoperative culture, which can guide the optimization and improve the sensitivity of intraoperative culture. Cite this article: Bone Joint J 2021;103-B(1):39–45

Aims. The diagnosis of periprosthetic joint infection (PJI) has always been challenging. Recently, D-dimer has become a promising biomarker in diagnosing PJI. However, there is controversy regarding its diagnostic value. We aim to investigate the diagnostic value of D-dimer in comparison to ESR and CRP. Methods. PubMed, Embase, and the Cochrane Library were searched in February 2020 to identify articles reporting on the diagnostic value of D-dimer on PJI. Pooled analysis was conducted to investigate the diagnostic value of D-dimer, CRP, and ESR. Results. Six studies with 1,255 cases were included (374 PJI cases and 881 non-PJI cases). Overall D-dimer showed sensitivity of 0.80 (95% confidence interval (CI) 0.69 to 0.87) and specificity of 0.76 (95% CI 0.63 to 0.86). Sub-group analysis by excluding patients with thrombosis and hyper-coagulation disorders showed sensitivity of 0.82 (95% CI 0.70 to 0.90) and specificity of 0.80 (95% CI 0.70 to 0.88). Serum D-dimer showed sensitivity of 0.85 (95% CI 0.76 to 0.92), specificity of 0.83 (95% CI 0.74 to 0.90). Plasma D-dimer showed sensitivity of 0.67 (95% CI 0.60 to 0.73), specificity of 0.58 (95% CI 0.45 to 0.72). CRP showed sensitivity of 0.78 (95% CI 0.72 to 0.83), specificity of 0.81 (95% CI 0.72 to 0.87). ESR showed sensitivity of 0.68 (95% CI 0.63 to 0.73), specificity of 0.83 (95% CI 0.78 to 0.87). Conclusion. In patients without thrombosis or a hyper-coagulation disorder, D-dimer has a higher diagnostic value compared to CRP and ESR. In patients with the aforementioned conditions, D-dimer has higher sensitivity but lower specificity compared to ESR and CRP. We do not recommend the use of serum D-dimer in patients with thrombosis and hyper-coagulation disorders for diagnosing PJI. Serum D-dimer may perform better than plasma D-dimer. Further studies are needed to compare serum D-dimer and plasma D-dimer in arthroplasty patients. Cite this article: Bone Joint Res 2020;9(10):701–708

Objectives. The diagnosis of surgical site infection following endoprosthetic reconstruction for bone tumours is frequently a subjective diagnosis. Large clinical trials use blinded Central Adjudication Committees (CACs) to minimise the variability and bias associated with assessing a clinical outcome. The aim of this study was to determine the level of inter-rater and intra-rater agreement in the diagnosis of surgical site infection in the context of a clinical trial. Materials and Methods. The Prophylactic Antibiotic Regimens in Tumour Surgery (PARITY) trial CAC adjudicated 29 non-PARITY cases of lower extremity endoprosthetic reconstruction. The CAC members classified each case according to the Centers for Disease Control (CDC) criteria for surgical site infection (superficial, deep, or organ space). Combinatorial analysis was used to calculate the smallest CAC panel size required to maximise agreement. A final meeting was held to establish a consensus. Results. Full or near consensus was reached in 20 of the 29 cases. The Fleiss kappa value was calculated as 0.44 (95% confidence interval (CI) 0.35 to 0.53), or moderate agreement. The greatest statistical agreement was observed in the outcome of no infection, 0.61 (95% CI 0.49 to 0.72, substantial agreement). Panelists reached a full consensus in 12 of 29 cases and near consensus in five of 29 cases when CDC criteria were used (superficial, deep or organ space). A stable maximum Fleiss kappa of 0.46 (95% CI 0.50 to 0.35) at CAC sizes greater than three members was obtained. Conclusions. There is substantial agreement among the members of the PARITY CAC regarding the presence or absence of surgical site infection. Agreement on the level of infection, however, is more challenging. Additional clinical information routinely collected by the prospective PARITY trial may improve the discriminatory capacity of the CAC in the parent study for the diagnosis of infection. Cite this article: J. Nuttall, N. Evaniew, P. Thornley, A. Griffin, B. Deheshi, T. O’Shea, J. Wunder, P. Ferguson, R. L. Randall, R. Turcotte, P. Schneider, P. McKay, M. Bhandari, M. Ghert. The inter-rater reliability of the diagnosis of surgical site infection in the context of a clinical trial. Bone Joint Res 2016;5:347–352. DOI: 10.1302/2046-3758.58.BJR-2016-0036.R1

Developmental dysplasia of the hip (DDH) should be diagnosed as early as possible to optimise treatment. The current United Kingdom recommendations for the selective screening of DDH include a clinical examination at birth and at six weeks. In Northern Ireland babies continue to have an assessment by a health visitor at four months of age. As we continue to see late presentations of DDH, beyond one year of age, we hypothesised that a proportion had missed an opportunity for earlier diagnosis. We expect those who presented to our service with Tonnis grade III or IV hips and decreased abduction would have had clinical signs at their earlier assessments. We performed a retrospective review of all patients born in Northern Ireland between 2008 and 2010 who were diagnosed with DDH after their first birthday. There were 75 856 live births during the study period of whom 645 children were treated for DDH (8.5 per 1000). The minimum follow-up of our cohort from birth, to detect late presentation, was four years and six months. Of these, 32 children (33 hips) were diagnosed after their first birthday (0.42 per 1000). With optimum application of our selective screening programme 21 (65.6%) of these children had the potential for an earlier diagnosis, which would have reduced the incidence of late diagnosis to 0.14 per 1000. As we saw a peak in diagnosis between three and five months our findings support the continuation of the four month health visitor check. Our study adds further information to the debate regarding selective versus universal screening. . Cite this article: Bone Joint J 2015;97-B:1572–6

Aims. Diagnosis of cauda equina syndrome (CES) remains difficult; clinical assessment has low accuracy in reliably predicting MRI compression of the cauda equina (CE). This prospective study tests the usefulness of ultrasound bladder scans as an adjunct for diagnosing CES. Methods. A total of 260 patients with suspected CES were referred to a tertiary spinal unit over a 16-month period. All were assessed by Board-eligible spinal surgeons and had transabdominal ultrasound bladder scans for pre- and post-voiding residual (PVR) volume measurements before lumbosacral MRI. Results. The study confirms the low predictive value of ‘red flag’ symptoms and signs. Of note ‘bilateral sciatica’ had a sensitivity of 32.4%, and a positive predictive value (PPV) of only 17.2%, and negative predictive value (NPV) 88.3%. Use of a PVR volume of ≥ 200 ml was a demonstrably more accurate test for predicting cauda equina compression on subsequent MRI (p < 0.001). The PVR sensitivity was 94.1%, specificity 66.8%, PPV 29.9% and NPV 98.7%. The PVR allowed risk-stratification with 13% patients deemed ‘low-risk’ of CES. They had non-urgent MRI scans. None of the latter scans showed any cauda equina compression (p < 0.006) or individuals developed subsequent CES in the intervening period. There were considerable cost-savings associated with the above strategy. Conclusion. This is the largest reported prospective evaluation of suspected CES. Use of the PVR volume ≥ 200 ml was considerably more accurate in predicting CES. It is a useful adjunct to conventional clinical assessment and allows risk-stratification in managing suspected CES. If adopted widely it is less likely incomplete CES would be missed. Cite this article: Bone Joint J 2020;102-B(6):677–682

Aims. Microbiological culture is a key element in the diagnosis of periprosthetic joint infection (PJI). However, cultures of periprosthetic tissue do not have optimal sensitivity. One of the main reasons for this is that microorganisms are not released from the tissues, either due to biofilm formation or intracellular persistence. This study aimed to optimize tissue pretreatment methods in order to improve detection of microorganisms. Methods. From December 2017 to September 2019, patients undergoing revision arthroplasty in a single centre due to PJI and aseptic failure (AF) were included, with demographic data and laboratory test results recorded prospectively. Periprosthetic tissue samples were collected intraoperatively and assigned to tissue-mechanical homogenization (T-MH), tissue-manual milling (T-MM), tissue-dithiothreitol (T-DTT) treatment, tissue-sonication (T-S), and tissue-direct culture (T-D). The yield of the microbial cultures was then analyzed. Results. A total of 46 patients were enrolled, including 28 patients in the PJI group and 18 patients in the AF group. In the PJI group, 23 cases had positive culture results via T-MH, 22 cases via T-DTT, 20 cases via T-S, 15 cases via T-MM, and 13 cases via T-D. Three cases under ongoing antibiotic treatment remained culture-negative. Five tissue samples provided the optimal yield. Any ongoing antibiotic treatment had a relevant influence on culture sensitivity, except for T-DTT. Conclusion. T-MH had the highest sensitivity. Combining T-MH with T-DTT, which requires no special equipment, may effectively improve bacterial detection in PJI. A total of five periprosthetic tissue biopsies should be sampled in revision arthroplasty for optimal detection of PJI. Cite this article: Bone Joint Res 2021;10(2):96–104

Aims. This pilot study tested the performance of a rapid assay for diagnosing prosthetic joint infection (PJI), which measures synovial fluid calprotectin from total hip and knee revision patients. Methods. A convenience series of 69 synovial fluid samples from revision patients at the Norfolk and Norwich University Hospital were collected intraoperatively (52 hips, 17 knees) and frozen. Synovial fluid calprotectin was measured retrospectively using a new commercially available lateral flow assay for PJI diagnosis (Lyfstone AS) and compared to International Consensus Meeting (ICM) 2018 criteria and clinical case review (ICM-CR) gold standards. Results. According to ICM, 24 patients were defined as PJI positive and the remaining 45 were negative. The overall accuracy of the lateral flow test compared to ICM was 75.36% (52/69, 95% CI 63.51% to 84.95%), sensitivity and specificity were 75.00% (18/24, 95% CI 53.29% to 90.23%) and 75.56% (34/45, 95% CI 60.46% to 87.12%), respectively, positive predictive value (PPV) was 62.07% (18/29, 95% CI 48.23% to 74.19%) and negative predictive value (NPV) was 85.00% (34/40, 95% CI 73.54% to 92.04%), and area under the receiver operating characteristic (ROC) curve (AUC) was 0.78 (95% CI 0.66 to 0.87). Patient data from discordant cases were reviewed by the clinical team to develop the ICM-CR gold standard. The lateral flow test performance improved significantly when compared to ICM-CR, with accuracy increasing to 82.61% (57/69, 95% CI 71.59% to 90.68%), sensitivity increasing to 94.74% (18/19, 95% CI 73.97% to 99.87%), NPV increasing to 97.50% (39/40, 95% CI 85.20% to 99.62%), and AUC increasing to 0.91 (95% CI 0.81 to 0.96). Test performance was better in knees (100.00% accurate (17/17, 95% CI 80.49% to 100.00%)) compared to hips (76.92% accurate (40/52, 95% CI 63.16% to 87.47%)). Conclusion. This study demonstrates that the calprotectin lateral flow assay could be an effective diagnostic test for PJI, however additional prospective studies testing fresh samples are required. Cite this article:Bone Joint Res. 2020;9(5):202–210

Aims. The purpose of this study was to validate our hypothesis that centrifugation may eliminate false-positive leucocyte esterase (LE) strip test results caused by autoimmune diseases in the diagnosis of knee infection. Methods. Between January 2016 and May 2019, 83 cases, including 33 cases of septic arthritis and 50 cases of aseptic arthritis, were enrolled in this study. To further validate our hypothesis, another 34 cases of inflammatory arthritis from the Department of Rheumatology of our institution were also included. After aspiration, one drop of synovial fluid was applied to LE strips before and after centrifugation. The results were recorded after approximately three minutes according to the different colour grades on the colour chart. The differences of LE results between each cohort were analyzed. Results. Before centrifugation, 46% (23/50) of the LE strip tests in the aseptic arthritis group were false-positives. Most of the false-positive results were due to inflammatory arthritis; after centrifugation, 78.3% (18/23) of the tests yielded negative results. Similar results were observed in cases from the Department of Rheumatology. The sensitivity of the centrifuged LE strip test was 0.818 (0.639 to 0.924), which is still an acceptable level compared with the uncentrifuged results, which yielded a sensitivity of 0.909 (0.745 to 0.976). However, the specificity was increased from 0.540 (0.395 to 0.679) to 0.900 (0.774 to 0.963) after centrifugation. Conclusion. Although inflammatory arthritis can yield a false-positive LE strip test result in the diagnosis of knee infection, centrifugation may eliminate these false-positive results. Cite this article: Bone Joint Res. 2020;9(5):236–241

Objectives. Circulating exosomes represent novel biomarkers for multiple diseases. In this study, we investigated whether circulating exosome levels could be used as a diagnostic biomarker for steroid-induced osteonecrosis of the femoral head (ONFH). Methods. We assessed the serum exosome level of 85 patients with steroid-induced ONFH and 115 healthy donors by Nanosight detection. We then assessed the diagnostic accuracy of serum exosomes by receiver operating characteristic curve analysis. Results. The circulating exosome level of the ONFH group was significantly lower than that of control group. The area under the curve was 0.72, suggesting that the level of serum exosomes has moderate diagnostic accuracy for steroid-induced ONFH. Conclusion. Circulating exosome levels are valuable in the diagnosis of steroid-induced ONFH. Cite this article: H-Y. Zhu, Y-C. Gao, Y. Wang, C-Q. Zhang. Circulating exosome levels in the diagnosis of steroid-induced osteonecrosis of the femoral head. Bone Joint Res 2016;5:276–279. DOI: 10.1302/2046-3758.56.BJR-2015-0014.R1

Aims. The aims of this study were to increase the diagnostic accuracy of the analysis of synovial fluid in the differentiation of prosthetic joint infection (PJI) by the addition of inexpensive biomarkers such as the levels of C-reactive protein (CRP), adenosine deaminase (ADA), alpha-2-macrogloblulin (α2M) and procalcitonin. Patients and Methods. Between January 2013 and December 2015, synovial fluid and removed implants were requested from 143 revision total joint arthroplasties. A total of 55 patients met inclusion criteria of the receipt of sufficient synovial fluid, tissue samples and removed implants for analysis. The diagnosis of PJI followed the definition from a recent International Consensus Meeting to create two groups of patients; septic and aseptic. Using receiver operating characteristic curves we determined the cutoff values and diagnostic accuracy for each marker. Results. There were 23 PJIs and 32 patients with aseptic loosening. The levels of total leucocyte count, proportion of polymorphonuclear leucocytes (PMNs), CRP, ADA and α2M in the synovial fluid were all significantly higher in those with a PJI than in those with aseptic loosening. The levels of procalcitonin were comparable in the two groups. Cutoff values for the optimal performance in the diagnosis of infection were: total leucocyte count > 1463 cells/μL (sensitivity (Sens) 100%, specificity (Spec) 71.9%, positive predictive value (PPV) 71.9%, negative predictive value (NPV) 100%); proportion of PMNs > 81% (Sens 78.3%, Spec 75.0%, PPV 69.2%, NPV 82.8%); CRP > 6.7mg/L (Sens 78.3%, Spec 93.8%, PPV 90.0%, NPV 85.7%); ADA > 61U/L (Sens 78.3%, Spec 96.9%, PPV 94.7%, NPV 86.1%) and α2M > 958 mg/L (Sens 47.8%, Spec 96.9%, PPV 91.7%, NPV 72.1%). The addition of a raised level of CRP or ADA to the total leukocyte count increased the specificity: total leukocyte count > 1463 cells/μL and CRP > 6.7mg/L (Sens 78.3%, Spec 100%, PPV 100%, NPV 86.5%) or with ADA > 61U/L (Sens 78.3%, Spec 96.9%, PPV 94.7%, NPV 86.1%). . Conclusion. The total leucocyte count in the synovial fluid offers great negative predictive value in the diagnosis of PJI and the addition of more specific markers such as CRP and ADA improves the positive predictive value. Thus the addition of simple and inexpensive markers to the measurement of the leucocyte count in the synovial fluid may reduce the number of equivocal results which demand more expensive investigation. Cite this article: Bone Joint J 2017;99-B:351–7

Aims. The aim of this study was to determine the diagnostic accuracy of α defensin (AD) lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) tests for periprosthetic joint infection (PJI) in comparison to conventional synovial white blood cell (WBC) count and polymorphonuclear neutrophil percentage (PMN%) analysis. Methods. Patients undergoing joint aspiration for evaluation of pain after total knee arthroplasty (TKA) or total hip arthroplasty (THA) were considered for inclusion. Synovial fluids from 99 patients (25 THA and 74 TKA) were analyzed by WBC count and PMN% analysis, AD LFA, and AD ELISA. WBC and PMN% cutoffs of ≥ 1,700 cells/mm. 3. and ≥ 65% for TKA and ≥ 3,000 cells/mm. 3. and ≥ 80% for THA were used, respectively. A panel of three physicians, all with expertise in orthopaedic infections and who were blinded to the results of AD tests, independently reviewed patient data to diagnose subjects as with or without PJI. Consensus PJI classification was used as the reference standard to evaluate test performances. Results were compared using McNemar’s test and area under the receiver operating characteristic curve (AUC) analysis. Results. Expert consensus classified 18 arthroplasies as having failed due to PJI and 81 due to aseptic failure. Using these classifications, the calculated sensitivity and specificity of AD LFA was 83.3% (95% confidence interval (CI) 58.6 to 96.4) and 93.8% (95% CI 86.2 to 98.0), respectively. Sensitivity and specificity of AD ELISA was 83.3% (95% CI 58.6 to 96.4) and 96.3% (95% CI 89.6 to 99.2), respectively. There was no statistically significant difference between sensitivity (p = 1.000) or specificity (p = 0.157) of the two AD assays. AUC for AD LFA was 0.891. In comparison, AUC for synovial WBC count, PMN%, and the combination of the two values was 0.821 (sensitivity p = 1.000, specificity p < 0.001), 0.886 (sensitivity p = 0.317, specificity p = 0.011), and 0.926 (sensitivity p = 0.317, specificity p = 0.317), respectively. Conclusion. The diagnostic accuracy of synovial AD for PJI diagnosis is comparable and not statistically superior to that of synovial WBC count plus PMN% combined. Cite this article: Bone Joint J 2021;103-B(6):1119–1126

Aims. The purpose of this study was to validate the diagnosis of periprosthetic joint infection (PJI) in the Danish Hip Arthroplasty Register (DHR). Patients and Methods. We identified a cohort of patients from the DHR who had undergone primary total hip arthroplasty (THA) since 1 January 2005 and followed them until first-time revision, death, emigration or until 31 December 2012. Revision for PJI, as registered in the DHR, was validated against a benchmark which included information from microbiology databases, prescription registers, clinical biochemistry registers and clinical records. We estimated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PJI in the DHR alone and in the DHR when combined with microbiology databases. Results. In total, 1382 of the 37 826 primary THAs in the DHR were registered as having been revised for any cause once 26 patients with errors in registration had been excluded: 232 of these were for PJI. For this group, the sensitivity was 67%, specificity 95%, PPV 77%, and NPV 92%. Combining the data from the DHR with those from microbiology databases increased the sensitivity to 90% and also improved specificity (100%), PPV (98%) and NPV (98%). Conclusion. Only two thirds of revisions for PJI were captured in the DHR and only 77% of the PJI reported to the DHR could be confirmed to be infected. . Take home message: combining the data from the DHR with those from microbiology databases substantially improved the validity of the diagnosis of PJI and should enable future register-based studies. Cite this article: Bone Joint J 2016;98-B:320–5

We evaluated the diagnostic accuracy of fine-needle aspiration biopsy in a prospective study of 300 patients with previously undiagnosed bone lesions. Patients with suspected local recurrence of a primary bone tumour or a metastatic lesion of a previously diagnosed malignancy were excluded. Fine-needle aspiration biopsy was performed under radiological control as an outpatient procedure. The series was grouped into three major categories: 1) benign bone lesions including infections; 2) primary malignant bone tumours; and 3) metastases including lymphomas and myelomas. We compared the cytological diagnosis with the final diagnosis as assessed by histological examination and/or the clinical and radiological features. Material considered conclusive for cytological diagnosis was obtained from 251 of the 300 patients. Of the 49 failures, there were 24 aspirates with insufficient cellular yield and 25 in which a diagnosis could not be made although the cytological material was adequate in quantity. Most of the inconclusive aspirates (36/49) were obtained from benign bone lesions. The diagnosis was correct in 239 (95%) of the 251 cases providing adequate cytological material. There were eight (3%) falsely benign diagnoses, one (0.3%) falsely malignant, and three cases in which we were unable to differentiate between sarcoma and a metastasis. Chondrosarcoma (2/12) gave the greatest diagnostic difficulty and Ewing’s sarcoma the least (0/9). There were no decisive errors of treatment. All falsely benign or malignant diagnoses were questioned, and led to open biopsy since they did not correlate with the clinical and radiological features. Our study suggests that fine-needle aspiration biopsy is a valid option for the diagnosis of bone tumours. It is a simple outpatient procedure which gives sufficient cytological material for the correct diagnosis in 80% of cases. As with histological analysis of material from open biopsy, the cytological assessment must agree with the clinical and radiological findings

We investigated the eventual diagnosis in patients referred to a tertiary centre with a possible diagnosis of a primary bone malignancy. We reviewed our database from between 1986 and 2010, during which time 5922 patients referred with a suspicious bone lesion had a confirmed diagnosis. This included bone sarcoma in 2205 patients (37%), benign bone tumour in 1309 (22%), orthopaedic conditions in 992 (17%), metastatic disease in 533 (9%), infection in 289 (5%) and haematological disease in 303 (5%). There was a similar frequency of all diagnoses at different ages except for metastatic disease. Only 0.6% of patients (17 of 2913) under the age of 35 years had metastatic disease compared with 17.1% (516 of 3009) of those over 35 years (p < 0.0001). Of the 17 patients under 35 years with metastatic disease, only four presented with an isolated lesion, had no past history of cancer and were systematically well. Patients under the age of 35 years should have suitable focal imaging (plain radiography, CT or MRI) and simple systemic studies (blood tests and chest radiography). Reduction of the time to biopsy can be achieved by avoiding an unnecessary investigation for a primary tumour to rule out metastatic disease

Aims. The diagnosis of periprosthetic joint infection (PJI) remains demanding due to limitations of all the available diagnostic tests. The synovial fluid marker, α-defensin, is a promising adjunct for the assessment of potential PJI. The purpose of this study was to investigate the qualitative assessment of α-defensin, using Synovasure to detect or exclude periprosthetic infection in total joint arthroplasty. Patients and Methods. We studied 50 patients (28 women, 22 men, mean age 65 years; 20 to 89) with a clinical indication for revision arthroplasty who met the inclusion criteria of this prospective diagnostic study. The presence of α-defensin was determined using the qualitative Synovasure test and compared with standard diagnostic methods for PJI. Based on modified Musculoskeletal Infection Society (MSIS) criteria, 13 cases were categorised as septic and 36 as aseptic revisions. One test was inconclusive. Results. The Synovasure test achieved a sensitivity of 69% and a specificity of 94%. The positive and negative likelihood ratios were 12.46 and 0.33, respectively. A good diagnostic accuracy for PJI, with an area under the curve of 0.82, was demonstrated. Adjusted p-values using the method of Hochberg showed that Synovasure is as good at diagnosing PJI as histology (p = 0.0042) and bacteriology with one positive culture (p = 0.0327). Conclusion. With its ease of use and rapid results after approximately ten minutes, Synovasure may be a useful adjunct in the diagnosis of PJI. Cite this article: Bone Joint J 2017;99-B:66–72

A delay in the diagnosis of paediatric acute and subacute haematogenous osteomyelitis can lead to potentially devastating morbidity. There are no definitive guidelines for diagnosis, and recommendations in the literature are generally based on expert opinions, case series and cohort studies. All articles in the English literature on paediatric osteomyelitis were searched using MEDLINE, CINAHL, EMBASE, Google Scholar, the Cochrane Library and reference lists. A total of 1854 papers were identified, 132 of which were examined in detail. All aspects of osteomyelitis were investigated in order to formulate recommendations. On admission 40% of children are afebrile. The tibia and femur are the most commonly affected long bones. Clinical examination, blood and radiological tests are only reliable for diagnosis in combination. Staphylococcus aureus is the most common organism detected, but isolation of Kingella kingae is increasing. Antibiotic treatment is usually sufficient to eradicate the infection, with a short course intravenously and early conversion to oral treatment. Surgery is indicated only in specific situations. Most studies were retrospective and there is a need for large, multicentre, randomised, controlled trials to define protocols for diagnosis and treatment. Meanwhile, evidence-based algorithms are suggested for accurate and early diagnosis and effective treatment

In 52 patients we compared the accuracy of standard anteroposterior (AP) radiography, mortise radiography and MRI with arthroscopy of the ankle for the diagnosis of a tear of the tibiofibular syndesmosis. In comparison with arthroscopy, the sensitivity, specificity and accuracy were 44.1%, 100% and 63.5% for standard AP radiography and 58.3%, 100% and 71.2% for mortise radiography. For MRI they were 100%, 93.1% and 96.2% for a tear of the anterior inferior tibiofibular ligament and 100%, 100% and 100% for a tear of the posterior inferior tibiofibular ligament. Standard AP and mortise radiography did not always provide a correct diagnosis. MRI was useful although there were two-false positive cases. We suggest that arthroscopy of the ankle is indispensable for the accurate diagnosis of a tear of the tibiofibular syndesmosis