Dynamic stabilization of chronic scapholunate dissociation with palmaris longus transfer: a new technique.

This report presents a new procedure of palmaris longus tendon transfer to the scaphoid and lunate, with reconstruction of the scapholunate ligament in chronic scapholunate dissociation. From 1988 to 2006, 10 cases of dynamic stabilization of chronic scapholunate dissociation were treated by palmaris longus tendon transfer to the scaphoid and lunate. The tendon transfer to the scaphoid and the reconstructed scapholunate ligament appeared to create a resultant force that corrected the scaphoid drift. The transfer to the lunate neutralized its dorsal intercalary segment instability posture. A normal scapholunate interval was restored at about 2 years postoperatively, and the lunate malrotation remained permanently corrected. Recovery of the scapholunate interval paralleled the recovery of the scapholunate angle and grip strength. These remained unchanged with long-term follow-up of between 3 and 18 years. The tendon transfer appeared to function like other tendon transfers in the upper extremity, providing active stabilization of the scaphoid and the lunate despite increasing loads on the wrist. Unfortunately, in the absence of symptoms of peripheral nerve entrapment, insurance approval could not be obtained for electromyography studies to document the activity of the transferred tendon. The forces of tendon transfer on the scaphoid and the reconstructed scapholunate ligament seem to generate a resultant force that acted on the scaphoid to maintain it in its fossa. The tendon transfer to the lunate corrected the dorsal intercalary segment instability orientation of the lunate at long-term follow-up of up to 18 years.