Immediate repair and early mobilization of the extensor pollicis longus tendon in zones 1 to 4.

We present the results of repair and early mobilization of 100 extensor pollicis longus (EPL) tendon injuries in zones 1 to 4 in 100 patients using a dynamic outrigger splint which controlled metacarpophalangeal joint movements but allowed free movement of the interphalangeal joint. Eighty-two were complete divisions of the tendon and 18 were 80% to 99% tendon divisions. Analysis of measurements obtained routinely at 8 weeks showed 81% excellent and good results using the TAM system. There were 90% excellent and good results in the 72 patients, who were followed-up and received therapy for 12 weeks. Except on the rare occasion when the repair rupture, loss of thumb extension was not a common functional problem, but scar tethering of the repaired tendon could result in loss of thumb flexion. While loss of metacarpophalangeal joint flexion appeared to have little functional importance, loss of interphalangeal joint flexion and slowing of the movements of this joint could cause functional problems. When interphalangeal joint hyperextension is present before the injury, it is frequently lost but this generally goes unnoticed by the patients. The problems of analysing the EPL injury using the methods of assessment available are discussed.