Osteoarthritis (OA) is the most prevalent rheumatologic disease and a leading cause of years lived with disability worldwide. There are no disease-modifying drugs available to treat it. This study aimed to evaluate the effect of a single dose of 100U botulinum neurotoxin-A (BoNT-A) in patients with early knee OA. We designed a single-arm preliminary clinical trial in patients diagnosed with knee OA (KOA) grades I and II. 45 Patients received a single dose of 100U IncobotulinumtoxinA in the retro-patellar bursa and received nutritional and physical rehabilitation indications. Patients were evaluated at baseline and at days 5, 30, 60, and 90 after injection. The primary outcome was the reduction in pain using the visual analog scale (VAS). Knee function was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). We assessed secondary adverse effects and measured muscular strength in every consultation. Descriptive endpoint summaries and a generalized linear random-effect model were used to evaluate changes in each follow-up time compared to baseline. IncobotulinumtoxinA treatment significantly (p < 0.001) reduced pain in all treated patients at day 90 compared to day 0. Patients showed a significant reduction in total WOMAC score (p < 0.001), from a mean baseline of 44.6 (95% CI; 41.4, 47.8) to 4.4 at day 90 (95% CI; 0.2, 0.3). Our results show that IncobotulinumtoxinA applied in the retro-patellar bursa is a safe and effective treatment for pain in patients with early-stage KOA, offering a potential alternative for symptomatic control in KOA.
Keywords: IncobotulinumtoxinA; botulinum toxins; case series; knee OA; osteoarthritis; pain.