Botulinum Toxin A (BTA) for pain and function improvement in osteoarthritis: a systematic review and meta-analysis of clinical efficacy evidence from randomized controlled trials.

[OBJECTIVE] To evaluate the effectiveness of botulinum toxin A injections in improving pain and function in patients with osteoarthritis.

[DESIGN] This study systematically searched the PubMed, Web of Science, Embase, Medline, Cochrane Library, CNKI, and Wanfang databases. The primary outcome was the Visual Analogue Scale (VAS), while secondary outcomes included the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the occurrence of adverse events.

[RESULTS] A total of eight randomized controlled trials (RCTs) were included. Seven studies compared VAS scores between the experimental and control groups, while three studies compared WOMAC scores. Both VAS and WOMAC scores were significantly lower in the experimental group than in the control group (P < 0.00001). In addition, different sites of OA (P = 0.99), different doses of botulinum toxin A injection (P = 0.52), and different times of outcome assessment (P = 0.58) had similar effects in reducing VAS scores.

[CONCLUSIONS] BTA injections effectively relieve overall pain perception and resting pain, but their efficacy for pain associated with specific functional activities remains uncertain. The effects of low- and high-dose regimens on reducing VAS scores are comparable, supporting the preferential use of the low-dose regimen; however, the efficacy of BTA in improving joint function remains highly uncertain.