Therapeutic Effects of Intra-articular Botulinum Neurotoxin Versus Physical Therapy in Knee Osteoarthritis.

[BACKGROUND] Knee osteoarthritis (KOA) is the most common cause of chronic knee pain, and disability and different modalities have been used to improve pain and function. Botulinum toxin intra-articular injection is proposed to manage resistant joint pains.

[OBJECTIVES] This study was carried out to compare therapeutic effects of intra-articular botulinum neurotoxin (BTX) versus physical therapy (PT) in KOA.

[METHODS] In this single-blind randomized clinical trial, patients with KOA attending to Imam-Reza Hospital, Tehran, Iran, from June 2018 to March 2019 were enrolled. Patients who met the inclusion criteria were randomly divided into BTX receiving a single intra-articular dose of 100 units (250 units from disport brand) and PT groups. The study was described for patients, and informed consent forms were received. For assessment of the pain and related severity, the VAS score and KOOS scales were used. Post-intervention assessment was done 1, 3, and 6 months after the intervention. The level of significance was set at α = 0.05. All data analyses were performed with SPSS version 26 for windows.

[RESULTS] In this study, 50 patients were randomly divided into BTX and PT groups. All patients completed the study, and there was no loss to follow-up. There was no significant difference between demographic data of the two groups, including age and BMI. The VAS score was similar in the two groups at the beginning. KOOS subscales were not significantly different, but the quality of life was better in the BTX than the PT group (86.2 ± 15 vs. 72.1 ± 11.5, P < 0.001). One month after the intervention, all KOOS subscales were improved in the BTX group in comparison to the PT group (P < 0.001). This difference was statistically significant in the 3rd (P < 0.001 in all comparisons except Sport/Rec subscale in which P = 0.02) and 6th months (P < 0.001) after the intervention, and the improvement in all KOOS subscales and VAS score were higher in the BTX group than the PT group. The trend of KOOS subscales and VAS score was improved over time in the BTX (P < 0.001 in all tests), but the PT group showed no improvement (P > 0.05) except for Sport/Rec and VAS score (P < 0.001).

[CONCLUSIONS] Totally, it is concluded that the use of BTX can reduce pain and improve the function and quality of life in patients with KOA.