Superimposed electrical stimulation improves mobility of pre-stiff thumbs after ulnar collateral ligament injury of the metacarpophalangeal joint: a randomized study.

OBJECTIVE: This study aimed at testing the ability of the superimposed electrical stimulation technique to restore the mobility of pre-stiff thumbs after operative repair for rupture of the ulnar collateral ligament. MATERIAL AND METHODS: Eight patients demonstrating a pre-stiff metacarpophalangeal joint were involved in two rehabilitation sessions of a counterbalanced design. In the voluntary contraction session, they performed 20min of repeated active flexions of the impaired metacarpophalangeal joint. In the superimposed electrical stimulation session, they performed 20min of percutaneous neuromuscular electrical stimulations which were superimposed to voluntary flexion. RESULTS: Mean active range of motion improvement from pre- to post-session was significantly greater in the superimposed electrical stimulation condition compared to the voluntary contraction condition (11±5 deg versus 3±4 deg; P<0.01). CONCLUSION: Superimposing electrical stimulation to voluntary contractions is an efficient technique to improve active range of motion of the pre-stiff metacarpophalangeal joint of the thumb.