Treatment of Extensor Lag Using the Flexor Digitorum Superficialis after Crushing-Penetrating Injury to the Metacarpophalangeal Joint.

We previously reported the beneficial effects of tendon transfer to eliminate extension lag of the interphalangeal joints, using the extensor carpi radialis longus prolonged by palmaris longus tendon grafts after crushing-penetrating injuries around the metacarpophalangeal (MP) joint of the middle finger. We used the flexor digitorum superficialis (FDS) as the alternative donor muscle and treated two cases of severe crushing injuries to MP joint, and then obtained good outcomes.