The interosseous twitch: treatment with botulinum toxin.

We present an 18-yr-old softball player who underwent surgery for a glenoid labrum tear and subsequent placement of a pain catheter pump. One month after withdrawing the catheter, the patient developed uncontrollable movements of her fourth digit. Neurology did not think it was a true dystonia but administered multiple medications without any relief of her symptoms. Upon referral, it was thought there was isolated contraction of the fourth dorsal and second volar interosseous muscle that was causing her finger to twitch back and forth in the plane of her hand; botulinum toxin was injected into these two muscles with complete resolution of her symptoms and pain.