Radiosynovectomy is effective in thumb basal joint arthritis

Radiosynovectomy (RSO) describes the internal low-dose radiotherapy of the synovia via intra-articular administration of small radioactive particles. Since the introduction of biologics, the main aetiology of arthritic joints for RSO changed to mostly osteoarthritis with concordant change in typically affected joints. Thus, the effect of RSO in thumb basal joint arthritis (BJTh) with focus on osteoarthritis needs to be explored.

From 2017 to 2020, 219 BJTh were treated in 125 patients, 17 patients with rheumatoid arthritis (RA) and 108 patients with osteoarthritis (OA). The therapeutic effect was assessed using a four-step subjective scoring.

20% of the treated joints were symptom free, 48% had a very good response, 16% slight and 16% no response. RSO was performed in 71 patients singularly and in 54 patients repetitively. The mean response duration was 6.8 months with a maximum of 48 months. 35% of patients had post-therapeutic pain relief followed by relapse after 3 months. Response duration showed no significant difference the between first and repetitive therapy, primary responder and primary non-responder and RA and OA.

In thumb basal joint arthritis, RSO leads to response rates from 66 to 79%, mean response duration from 6 to 12 months and individual response duration 48 months. The present results are in line with previously published response rates in smaller joints. In respect to 35% of patients with relapse within 3 months post-therapy, we recommend a primary follow-up after 3-4 months.