Botulinum toxin type A in the treatment of painful adductor muscle contracture after total hip arthroplasty

Dystonia is a set of disorders characterized by abnormal postures and unwanted muscle spasms that interfere with motor performance. Focal dystonias, the most common, affect just 1 body part. A 25-year-old woman had a focal hand dystonia with pain and muscle spasms in the right hand after surgical treatment for thumb duplication. According to Wassel's classification, she was type II, with duplication of the distal phalanx. She had undergone Bilhaut-Cloquet surgery to remove a radial supernumerary thumb. During repetitive movements, she reported pain and muscle cramping in the right thumb and wrist. Force was rated, according to the Medical Research Council scale, from grades 0 to 5, and the patient had a score of 4. No sign of joint instability was found in her hand, and normal active and passive range of motion were found for interphalangeal or metacarpophalangeal joints of right thumb. However, right thenar muscle hypoplasia was found. Repetitive activity acted as an environmental trigger for the reconstructed thumb on thenar muscle hypoplasia as residual anatomical modification. Surface electromyography showed movements suggestive of dystonia. After 5 days of treatment with botulinum toxin type A, with both the flexor pollicis longus and the abductor pollicis brevis of right hand injected with a dose of 20 microM each, the patient reported a regression of most signs and symptoms. Two-month follow-up revealed that clinical effects of botulinum toxin type A were still present.