Comparison between intra-articular Botulinum toxin type A, corticosteroid, and saline in knee osteoarthritis: a randomized controlled trial

Objective: To compare the effectiveness of intra-articular injection (IAI) with Botulinum toxin type A (BTA), triamcinolone hexacetonide (TH), and saline in primary knee osteoarthritis. Design: A randomized controlled trial, with blinded patients and assessor. Setting: Outpatient rheumatology service. Subjects: Patients with knee osteoarthritis grades II and III. Interventions: Patients received IAI with 100 IU BTA, 40 mg TH, or isotonic saline solution (SS) 0.9%. Main measures: Patients were assessed at baseline and at 4, 8, and 12 weeks with the following instruments: visual analog scale for pain during movement (VASm; primary outcome) and visual analog scale for pain at rest (VASr), Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, 6-minute walk test, Timed Up and Go test, Short Form (SF)-36 questionnaire, range of motion of knee, and ultrasound (US) measurement of synovial hypertrophy. Results: In total, 105 patients were randomized, with 35 in each group; 96 were female (91.4%) and 9 were male (8.6%), with a mean age of 64.2 years (+/- 6.9). At 12 weeks, the TH group showed better results only for VASm. At four weeks, the TH group showed better results than the BTA and SS groups for VASm (-68.9% (37.8) vs. -35.3% (40.3) vs. -35.9% (51.4)), WOMAC pain (-56.0% (30.7) vs. -30.8% (34.3) vs. -30.0% (39.9)), WOMAC stiffness (-53.4% (38.4) vs. -17.2% (59.3) vs. -17.3% (78.1)), WOMAC function (-48.2% (34.6) vs. 30.8% (33.6) vs. -13.6% (64.9)), WOMAC total score (-51.2% (31.0) vs. -30.9% (30.0) vs. -18.8% (54.8)), and US measurement of synovial hypertrophy (-11.6% (44.9) vs. -1.5% (47.9) vs. +28.6% (81.3)). Conclusion: IAI with TH had a higher effectiveness than that with TBA or SS in the short-term assessment (four weeks) for pain in movement, WOMAC, and US measurement of synovial hypertrophy.