A modification of the palmaris longus-to-extensor pollicis longus transfer for radial nerve palsy

Purpose: The standard palmaris longus (PL)-to-rerouted extensor pollicis longus (EPL) transfer was modified by taking the PL with an extension of the palmar aponeurosis (PA) and performing the transfer at the level of the thumb metacarpal. Our purpose was to evaluate whether this modified transfer could restore both the extension and the radial abduction of the thumb without rerouting the EPL. Methods: We restored thumb function of 5 patients with unrecovered radial nerve palsy (4 men and 1 women; mean age at surgery, 47 years; mean duration between onset of palsy and surgery, 13 months; and mean follow-up period after surgery, 17 months). The PA was dissected in continuity with the PL (PA/PL) tendon, as is done in Camitz thumb opponensplasty. Another skin incision was made on the dorsal side of the thumb metacarpal, and the EPL tendon was exposed. The PA/PL tendon was drawn into this skin incision, passing under the abductor pollicis longus and extensor pollicis brevis tendons. The PA/PL tendon was woven into the undivided EPL tendon and immobilized for 3 weeks. Results: The mean values of active hyperextension and flexion of the interphalangeal joint, radial abduction, palmar abduction of the thumb, grip strength, and tip pinch strength of the involved/contralateral sides were 3°/7°, 41°/49°, 59°/65°, 65°/70°, 37 kg/47 kg, and 4.0 kg/5.2 kg, respectively. Discussion: We used the PA to lengthen the PL tendon, to transfer it to the EPL at a level distal to the Lister tubercle. Because our procedure is based on the concept of standard transfer, it should yield similar long-term results. Our procedure should be a good alternative, especially in cases of closed radial nerve injury, because it preserves the paralyzed EPL for possible future recovery. Type of study/level of evidence: Therapeutic IV.