Background Histological and bacteriological analysis of synovial tissue (ST) is useful for the diagnosis of undetermined monoarthritis or polyarthritis, especially if a septic arthritis or a villonodular synovitis is suspected. Ultrasound (US) allows an evaluation of the synovial tissue thickness and inflammation. It also helps to perform real-time synovial biopsy. The goal of this study was to describe the “real life” indications and results of US guided synovial biopsies.
Methods We retrospectively analyzed all synovial biopsies performed between January 2007 and December 2014 in the Rheumatology Department of Nantes University Hospital. Synovial biopsies were performed under real-time US guidance (Philips HD11 XE) using a semi-automatic core biopsy, with a 14 or 16G caliber Tru-cut needle. We collected all data with a standardized form including clinical data (indication, type of joint, side effects, final diagnosis); histological results (presence of synovial tissue, type of cell infiltrate) and microbiological results (PCR, bacteriological, fungal and mycobacterium cultures). We considered the procedure as successful if synovial tissue was found at the histological examination.
Results Seventy-four patients underwent 75 synovial biopsies. 46% were women and average age was 58,8 years. Biopsies were performed in the following joints: knee (n=42; 56%), ankle (n=7; 10%), wrist (n=7; 10%), shoulder (n=6; 8%), hip (n=4), sterno-clavicular joint (n=3), elbow (n=3), pubic symphysis (n=1), acromio-clavicular joint (n=1), first metatarsophalangeal joint (n=1). Patients presented a chronic monoarthritis in 43 cases (57%), an acute monoarthritis in 16 cases (21%), a chronic polyarthritis in 13 cases (17%), an acute polyarthritis, a chronic tenosynovitis and a chronic bursitis in 1 case respectively. Indications for the biopsies were a suspicion of septic arthritis in 64 cases (85%) or villo nodular synovitis in 11 cases (15%). Biopsy succeeded in 85% of cases (64 on 75 biopsies performed). When analyzing failed biopsies, we found either fibrin deposition (corresponding with thick synovial tissue visualized with US) or adipose tissue (corresponding with thin synovial tissue visualized with US or small joints). Ten biopsies on 64 resulted in definitive diagnosis: 1 case of amyloid arthritis on a patient having no known myeloma, 1 joint localization of a mantle cell lymphoma, 2 villonodular synovitis, 1 gouty arthritis, 1 osteochondromatosis, 2 septic arthritis (no bacteria found on cultures, but a typical histological aspect), 1 Whipple disease (positive PCR on synovial tissue) and 1 Lyme arthritis (positive PCR on synovial tissue). The histological analysis of the 54 other biopsies showed a non-specific cell infiltrate with lymphocytes and/or macrophages. One patient presented a knee hemarthrosis 48 hours after the US guided biopsy.
Conclusions US guided synovial biopsies success in 85% of cases. This technique allows to biopsy all joints, especially small joints as sterno-clavicular joint or pubic symphysis. Side effects are rare. Synovial biopsy allowed in one over eight cases to obtain a definitive diagnosis. In the 54 other cases, synovial biopsy excludes septic or tumoral synovitis, allowing intra articular injections of glucocorticoids or other immunosuppressive treatments.
Disclosure of Interest None declared