Aims. To explore the synovial expression of mucin 1 (MUC1) and its role in rheumatoid arthritis (RA), as well as the possible downstream mechanisms. Methods. Patients with qualified synovium samples were recruited from a RA cohort. Synovium from patients diagnosed as non-inflammatory orthopaedic arthropathies was obtained as control. The expression and localization of MUC1 in synovium and fibroblast-like synoviocytes were assessed by immunohistochemistry and immunofluorescence. Small interfering RNA and MUC1 inhibitor GO-203 were adopted for inhibition of MUC1. Lysophosphatidic acid (LPA) was used as an activator of Rho-associated pathway. Expression of inflammatory cytokines, cell migration, and invasion were evaluated using quantitative real-time polymerase chain reaction (PCR) and Transwell chamber assay. Results. A total of 63 RA patients and ten controls were included. Expression of MUC1 was observed in both the synovial lining and sublining layer. The percentage of MUC1+ cells in the lining layer of synovium was significantly higher in RA than that in control, and positively correlated to joint destruction scores of RA. Meanwhile, MUC1+ cells in the sublining layer were positively correlated to the Krenn subscore of inflammatory infiltration. Knockdown of MUC1, rather than GO-203 treatment, ameliorated the expression of proinflammatory cytokines, cell migration, and invasion of rheumatoid synoviocytes. Knockdown of MUC1 decreased expression of RhoA, Cdc42, and Rac1. Treatment with LPA compromised the inhibition of migration and invasion, but not inflammation, of synoviocytes by MUC1 knockdown. Conclusion. Upregulated MUC1 promotes the aggression of rheumatoid synoviocytes via Rho guanosine triphosphatases (GTPases), thereby facilitating synovitis and joint destruction during the pathological process of RA. Cite this article: Bone Joint Res 2022;11(9):639–651

The crucial differentiation between septic arthritis and transient synovitis of the hip in children can be difficult. In 1999, Kocher et al introduced four clinical predictors which were highly predictive (99.6%) of septic arthritis. These included fever (temperature ≥ 38.5°C), inability to bear weight, white blood-cell count > 12.0 × 10. 9. cells/L and ESR ≥ 40 mm/hr; CRP ≥ 20 mg/L was later added as a fifth predictor. We retrospectively evaluated these predictors to differentiate septic arthritis from transient synovitis of the hip in children over a four-year period in a primary referral general hospital. When all five were positive, the predicted probability of septic arthritis in this study was only 59.9%, with fever being the best predictor. When applied to low-prevalence diseases, even highly specific tests yield a high number of false positives and the predictive value is thereby diminished. Clinical predictors should be applied with caution when assessing a child with an irritable hip, and a high index of suspicion, and close observation of patients at risk should be maintained

Component malalignment can be associated with pain following total knee replacement (TKR). Using MRI, we reviewed 50 patients with painful TKRs and compared them with a group of 16 asymptomatic controls to determine the feasibility of using MRI in evaluating the rotational alignment of the components. Using the additional soft-tissue detail provided by this modality, we also evaluated the extent of synovitis within these two groups. Angular measurements were based on the femoral transepicondylar axis and tibial tubercle. Between two observers, there was very high interobserver agreement in the measurements of all values. Patients with painful TKRs demonstrated statistically significant relative internal rotation of the femoral component (p = 0.030). There was relative internal rotation of the tibial to femoral component and combined excessive internal rotation of the components in symptomatic knees, although these results were significant only with one of the observers (p = 0.031). There was a statistically significant association between the presence and severity of synovitis and painful TKR (p < 0.001). MRI is an effective modality in evaluating component rotational alignment

We used ultrasonography to examine 36 children suffering from transient synovitis and 12 children with early Perthes' disease. Widening of the joint space was revealed by ultrasonography in all affected hips with either disease. In the patients with transient synovitis, capsular distension was attributed to synovial effusion, while in the patients with Perthes' disease it was produced by thickening of the synovial membrane. Neither capsular distension nor thickening of the joint cartilage was seen in the contralateral normal hip in the patients with transient synovitis, but they were common in early Perthes' disease. Ultrasonography may provide significant diagnostic clues to differentiate early Perthes' from transient synovitis

The August 2024 Wrist & Hand Roundup. 360. looks at: Methotrexate shows potential in reducing pain for hand osteoarthritis with synovitis; Circumferential casting versus plaster splinting in adult distal radius fractures: the CAST study findings; Surgery shows superior long-term success for Dupuytren contracture compared to needle fasciotomy and collagenase injection; Evolving trends in surgical management of wrist arthritis: a decade-long national analysis; Mid-term outcomes of three commonly used surgical reconstructions for scapholunate instability; SLAC and SNAC: what is the evidence for treatment?; Steroids for trapeziometacarpal osteoarthritis?; When is it safe to return to driving after distal radius fracture fixation? A prospective study

Our experience of five children with chronic thorn synovitis indicates that removal of free thorn fragments and all the macroscopically abnormal synovium is required in order to achieve a complete cure. Four children required total synovectomy for diffuse proliferative synovitis and one needed partial synovectomy of the area immediately around the embedded thorn. Joint washouts and partial synovectomy were unsuccessful in children with diffuse synovitis. Careful review is required following removal of a thorn as fragments may be retained within the joint

Aims. The purpose of this study was to assess mid-term survivorship following primary total knee arthroplasty (TKA) with Optetrak Logic components and identify the most common revision indications at a single institution. Methods. We identified a retrospective cohort of 7,941 Optetrak primary TKAs performed from January 2010 to December 2018. We reviewed the intraoperative findings of 369 TKAs that required revision TKA from January 2010 to December 2021 and the details of the revision implants used. Kaplan-Meier analysis was used to determine survivorship. Cox regression analysis was used to examine the impact of patient variables and year of implantation on survival time. Results. The estimated survivorship free of all-cause revision was 98% (95% confidence interval (CI) 97% to 98%), 95% (95% CI 95% to 96%), and 86% (95% CI 83% to 88%) at two, five, and ten years, respectively. In 209/369 revisions there was a consistent constellation of findings with varying severity that included polyethylene wear and associated synovitis, osteolysis, and component loosening. This failure mode, which we refer to as aseptic mechanical failure, was the most common revision indication. The mean time from primary TKA to revision for aseptic mechanical failure was five years (5 months to 11 years). Conclusion. In this series of nearly 8,000 primary TKAs performed with a specific implant, we identified a lower-than-expected mid-term survivorship and a high number of revisions with a unique presentation. This study, along with the recent recall of the implant, confirms the need for frequent monitoring of patients with Optetrak TKAs given the incidence of polyethylene failure, osteolysis, and component loosening. Cite this article: Bone Joint J 2023;105-B(3):277–283

Aims. Pellino1 (Peli1) has been reported to regulate various inflammatory diseases. This study aims to explore the role of Peli1 in the occurrence and development of osteoarthritis (OA), so as to find new targets for the treatment of OA. Methods. After inhibiting Peli1 expression in chondrocytes with small interfering RNA (siRNA), interleukin (IL)-1β was used to simulate inflammation, and OA-related indicators such as synthesis, decomposition, inflammation, and apoptosis were detected. Toll-like receptor (TLR) and nuclear factor-kappa B (NF-κB) signalling pathway were detected. After inhibiting the expression of Peli1 in macrophages Raw 264.7 with siRNA and intervening with lipopolysaccharide (LPS), the polarization index of macrophages was detected, and the supernatant of macrophage medium was extracted as conditioned medium to act on chondrocytes and detect the apoptosis index. The OA model of mice was established by destabilized medial meniscus (DMM) surgery, and adenovirus was injected into the knee cavity to reduce the expression of Peli1. The degree of cartilage destruction and synovitis were evaluated by haematoxylin and eosin (H&E) staining, Safranin O/Fast Green staining, and immunohistochemistry. Results. In chondrocytes, knockdown of Peli1 produced anti-inflammatory and anti-apoptotic effects by targeting the TLR and NF-κB signalling pathways. We found that in macrophages, knockdown of Peli1 can inhibit M1-type polarization of macrophages. In addition, the corresponding conditioned culture medium of macrophages applied to chondrocytes can also produce an anti-apoptotic effect. During in vivo experiments, the results have also shown that knockdown Peli1 reduces cartilage destruction and synovial inflammation. Conclusion. Knockdown of Peli1 has a therapeutic effect on OA, which therefore makes it a potential therapeutic target for OA. Cite this article: Bone Joint Res 2023;12(2):121–132

A prospective study was made of 119 children with transient synovitis or any other cause for synovial effusion and elevated intra-articular pressure. During a follow-up of one year not one case of Perthes' disease was diagnosed and the late clinical and radiographic changes were minimal with moderate overgrowth of the femoral head in 33% and widening of the joint space in 14.2%. Our results do not support the widely accepted concept that Perthes' disease develops as a result of the period of elevated intra-articular pressure found in transient synovitis. Further research into this and Perthes' disease should follow the premise that they are two different diseases without any aetiological connection

Aims. To analyze the short-term outcome of two types of total wrist arthroplasty (TWA) in terms of wrist function, migration, and periprosthetic bone behaviour. Methods. A total of 40 patients suffering from non-rheumatoid wrist arthritis were enrolled in a randomized controlled trial comparing the ReMotion and Motec TWAs. Patient-rated and functional outcomes, radiological changes, blood metal ion levels, migration measured by model-based radiostereometric analysis (RSA), bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA), complications, loosening, and revision rates at two years were compared. Results. Patient-Rated Wrist and Hand Evaluation (PRWHE) scores, abbreviated version of the Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) scores, and pain improved similarly and significantly in both groups. Wrist motion improved significantly in the Motec group only, and forearm rotation in the ReMotion group only. Cobalt (Co) and chromium (Cr) blood ion levels were significantly higher in the metal-on-metal (MoM) Motec group than in the metal-on-polyethylene (MoP) ReMotion group. Mean total translation was 0.65 mm (95% confidence interval (CI) 0.26 to 1.12) and 0.27 mm (95% CI 0.14 to 0.47) for the ReMotion carpal and radial components, and 0.32 mm (95% CI 0.22 to 0.45) and 0.26 mm (95% CI 0.20 to 0.34) for the Motec metacarpal and radial components, respectively. Apart from dorsal and volar tilts, which were significantly higher for the radial ReMotion than for the Motec component, no significant differences in absolute migration occurred. BMD around the radial components never returned to baseline. Almost one-third of patients required reoperation due to complications. Two ReMotion implants were revised to Motec TWAs due to carpal component loosening, and three Motec MoM articulations were revised to metal-on-polyether ether ketone due to painful synovitis. Conclusion. Both implants provided matched function and were stable at short-term follow-up, but with a high complication rate. This procedure should be restricted to specialist centres undertaking prospective analysis until its role is clarified. Cite this article: Bone Joint J 2022;104-B(10):1132–1141

We have reviewed seven cases of synovitis caused by date palm thorns, six involving the knee and one the ankle. Five were satisfactorily treated by thorough irrigation of the joint with normal saline, but two required arthrotomy and synovectomy. All made a full recovery

The appearance and the biochemical, cytological and bacteriological findings were studied in synovial fluid obtained from the knees of 72 patients from south-west India. We report a group of 12 patients with 'eosinophilic synovitis'. In these patients, all below the age of 20 years with an acute onset of severe pain in the knee, there was a large effusion with painful limitation of movement. Their blood leucocyte count averaged 11,200 per mm3 with a mild eosinophilia of 6%. Biochemical examination of synovial fluid was normal, but cytology showed an increase in leucocytes ranging from 1200 to 20,500 (mean 9525) with between 75% and 90% of eosinophils in eight patients and 60% to 75% in four. All the patients responded well to a course of diethylcarbamazine

In a prospective five-year study, 294 episodes of acute transient synovitis of the hip were diagnosed in 275 children. The average annual incidence was 0.2% and the accumulated risk of suffering at least one episode was 3%. The risk of recurrence was 20 times greater than the risk of having a single episode. Perthes' disease was diagnosed from one to five months after the acute attack of synovitis in 10 cases (3.4%). Review of the initial radiographs revealed signs of avascular necrosis in three of the 10 cases, and an increased joint space in five. Only two cases had had completely normal radiographs. The value of routine radiographs taken after three months was minimal. Factors associated with the incidence of Perthes' disease included prolonged time in traction before the range of hip movement became normal, increase in joint space on the initial radiographs and the recurrence of hip symptoms after initial relief

We reviewed 15 children with transient synovitis of the hip who had aspiration of an effusion under local anaesthesia with ultrasound guidance. There were no significant complications; aspiration was useful for diagnosis and gave considerable symptomatic relief. We discuss the role of ultrasound in diagnosis and treatment

Background. Establishing the diagnosis in a child presenting with an atraumatic limp can be difficult. Clinical prediction algorithms have been devised to distinguish septic arthritis (SA) from transient synovitis (TS). Within Europe measurement of the Erythrocyte Sedimentation Rate (ESR) has largely been replaced with assessment of C-Reactive Protein (CRP) as an acute phase protein. We produce a prediction algorithm to determine the significance of CRP in distinguishing between TS and SA. Method. All children with a presentation of ‘atraumatic limp’ and a proven effusion on hip ultrasound between 2004 and 2009 were included. Patient demographics, details of the clinical presentation and laboratory investigations were documented to identify a response to each of the four variables (Weight bearing status, WCC >12,000 cells/m3, CRP >20mg/L and Temperature >38.5°C). SA was defined based upon culture and microscopy of the operative findings. Results. 311 hips were included within the study. Of these 282 were considered to have transient synovitis. 29 patients met criteria to be classified as SA based upon laboratory assessment of the synovial fluid. The introduction of CRP eliminated the need for a four variable model as the use of two variables (CRP and weight bearing status) had similar efficacy. Treating individuals who were non-weight-bearing and a CRP >20mg/L as SA correctly classified 94.8% individuals, with a sensitivity of 75.9%, specificity of 96.8%, positive predictive value of 71.0%, and negative predictive value of 97.5%. CRP was a significant independent predictor of septic arthritis. Conclusions. CRP was a strong independent risk factor of septic arthritis, and its inclusion within a regression model simplifies the diagnostic algorithm. Nevertheless, this and other models are generally more reliable in excluding SA, than confirming SA, and therefore a clinician's acumen remains important in identifying SA in those individuals with a single abnormal variable

Sonography was successfully used to diagnose an effusion in the hips of three adults with septic arthritis and four with aseptic synovitis. The effusions were confirmed by aspiration. All the patients had markedly increased intracapsular pressure which, in the extended position, exceeded the systolic blood pressure and could well compromise the blood supply to the head of femur. Aspiration reduced pain and intracapsular pressure, as did flexion of the hip to 45 degrees

The pathogenesis of Perthes' disease has been related to increased intra-articular pressure secondary to a joint effusion. The pressure within the hip in different positions was measured in eight children with transient synovitis and four with the synovial stage of Perthes' disease. In the position of comfort for the hip this pressure was always less than the arteriolar blood pressure and in a supine position it did not exceed the systolic blood pressure. However, in extension with medial rotation the intra-articular pressure always became several times the systolic blood pressure. This high pressure was also recorded in the stable lateral position which occurs normally during sleep. It is concluded that in the presence of a synovial effusion in the hip, a position of extension and medial rotation causes an increase in intra-articular pressure which may compromise the blood supply to the capital epiphysis of the femur

We evaluated histologically samples of synovial tissue from the knees of 50 patients with rheumatoid arthritis (RA). The samples were taken during revision for aseptic loosening. The findings were compared with those in 64 knees with osteoarthritis (OA) and aseptic loosening and in 18 knees with RA without loosening. The last group had been revised because of failure of the inlay or the coupling system of a constrained prosthesis. All the patients had had a total ventral synovectomy before implantation of the primary prosthesis. In all three groups a foreign-body reaction and lymphocellular infiltration were seen in more than 80% of the tissue samples. Deposits of fibrin were observed in about one-third to one-half of the knees in all groups. Typical signs of the reactivation of RA such as rheumatoid necrosis and/or proliferation of synovial stromal cells were found in 26% of knees with RA and loosening, but not in those with OA and loosening and in those with RA without loosening. Our findings show that reactivation of rheumatoid synovitis occurs after total knee replacement and may be a cofactor in aseptic loosening in patients with RA

Cite this article: Bone Joint Res 2022;11(8):514–517.

Pigmented villonodular synovitis (PVNS) is a rare benign neoplastic proliferation of synovial tissue which is typically localised and usually responds well to surgery and/or radiotherapy. We present a case of unusually aggressive of PVNS of the hip in a 73-year-old woman.