Surgical management of the hyperflexed thumb interphalangeal joint in the hand with ulnar intrinsic palsy

Abstract

A great deal of attention has been paid to the need to restore balance about the metacarpophalangeal joint when clawing complicates ulnar nerve palsy. Less commonly addressed but perhaps more disabling are the consequences of ulnar palsy on function of the thumb. The hyperflexion of the thumb’s interphalangeal joint (IPJ), popularly termed Froment’s sign, leads to an unstable pinch. When surgically addressed, a common recommendation is fusion of this joint. A simple operative procedure, introduced to provide stability to the tetraplegic hand as part of key grip reconstruction can be equally well applied to the hyperflexed thumb of ulnar nerve palsy. Tenodesis of one half of the flexor pollicis longus into the extensor pollicis longus provides a check-rein against excessive IPJ flexion, promotes a more stable pinch posture, and avoids fusion of the joint.