LAUSR

Background Persistent tenosynovitis and degenerative tendinitis is associated with pain and can lead to dysfunction and tendon damage. While tenosynovitis is a common finding in rheumatoid arthritis, data on tendon involvement in hand osteoarthritis (HOA) is clearly limited. The clinical assessment of tendons is difficult and not fully standardized, but muculoskeletal ultrasound (MSUS) has been used successfully in inflammatory rheumatic disease as a sensitive method to detect tenosynovitis, tendon damage and osteophytes. Objectives To characterize tendon involvement in hand osteoarthritis and compare ultrasound with clinical assessment. Methods In this cross-sectional observational study 34 patients with HOA underwent MSUS and clinical examination on the same day. Each flexor and extensor tendon of the hand was scored independently for tenosynovitis and tendon damage (presence/absence) respectively by an expert in MSUS, blinded to the results of the clinical examination. Additionally, osteophytes in the proximal and distal interphalangeal joints of the fingers were assessed. Clinical assessment of tendons for tendon involvement included volar or dorsal pain, crepitus and swelling involving the hand, wrist or forearm during active movement of the tendon against resistance according to the Birmingham consensus criteria, by assessors who were blinded to the results of the MSUS. Conventional radiographs (CR) of the hands were also acquired and evaluated by the Interphalangeal Osteoarthritis Radiographic Simplified score. Results The majority of patients (30/34, 88.2%) were female, with a mean age of 69.5±8.5 years and a median of 10 (9–22.5) years disease duration. Clinical examination revealed tendon involvement in 21 (61.8%) patients with a median of 3 (range 1–14) affected tendons. In MSUS tenosynovitis was detected in 17/33 patients (51.5%) with a median of 1 (1–4) tendon involved. Tendon damage was found in 8/33 patients (24.2%) with a median of 2 (1–11) tendons involved. A total of 20/33 (60.6%) patients exhibited sonographic signs of tendon involvement (tenosynovitis/tendon damage) with a median of 2 (1–12) involved tendons. Tendon damage was found more often on the right hand (p<0.05) while tenosynovitis did not significantly differ. Similarly, no significant difference between male and female patients was found. The extensor digitorum and the extensor carpi ulnaris tendons were the most commonly affected tendons under US. Tenosynovitis was found to be more prevalent among extensor tendons (p<0.001), while tendon damage was demonstrated at a higher frequency in flexor tendons (p<0.05) (Fig. 1). The agreement between MSUS and clinical examination was moderate on the patient level and poor on the level of individual tendons. Osteophytes were found in 96.8% patients using MSUS and in 100% of patients assessed using CR. Osteophytes detected on MSUS or CR showed good agreement (p=0.01, Cronbach's Alpha=0.66). Conclusions The findings of our study reveal a high prevalence of tendon involvement in patients with hand OA. Sensitivity of MSUS in detecting tendon involvement coupled with the lack of agreement between clinical examination and MSUS on the level of individual tendons may suggest that while clinical examination is able to identify patients with overall tendon involvement, it does not allow the specific identification of involved tendons. Disclosure of Interest None declared