Botulinum Toxin type A injections for patients with painful hallux valgus: a double-blind, randomized controlled study.

Hallux valgus (HV) related pain and disability remains a medical challenge to date. We have evaluated the therapeutic effect of intramuscular Botulinum Toxin type A (BTX-A) injection on painful HV in a double-blind randomized controlled trial. Sixteen patients having painful HV in at least one foot from the Department of Physical Medicine and Rehabilitation at a medical center in northern Taiwan have participated. Patients were randomized into two groups to receive intramuscular injections of either BTX-A or normal saline (NS) to the oblique and transverse heads of the adductor hallucis, flexor hallucis brevis and extensor hallucis longus muscles. Primary outcome measurements were selected from the Taiwan Chinese version of the Foot Function Index subscales on pain (questions 1-6, 9) and disability (question 10-18). The secondary outcome measurement was the HV angle. Patients were assessed at baseline and at 1, 2, 3, and 6 months after treatment. The demographic data and measurements were comparable between the two groups at baseline (p>0.05). BTX-A and NS reduced pain and disability one month after injection. Pain reduction induced by BTX-A injection lasted for at least 6 months while that induced by NS lasted for only 1 month. In addition, patients in the BTX-A group showed greater improvement in pain score (p<0.001), disability score (p<0.05), and HV angle (p<0.05) than patients in the NS group. The results reflected that HV-related muscle injection of BTX-A resulted in a marked reduction in pain for up to 6 months.