Delayed reconstruction of a missed Extensor Pollicis Brevis and Abductor Pollicis Longus injury using tendon transfers and an onlay tendon graft: a case report

Delayed presentation of extensor tendon injury comes with unique challenges due to retraction of tendons, adhesions and problems of disuse of the muscles. We present a case report of tendon reconstruction eight months after a sharp injury to the Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL) tendon in zone VIII. The EPB was reconstructed by using an Extensor Indicis Proprius (EIP) to EPB transfer. The APL was found slack due to a large section of pseudotendon. After tenolysis the proximal tendon stump of the EPB was sutured to the APL, thus combining the impaired EPB and APL muscles for APL function. The slack section of pseudotendon of the APL was plicated to restore tension and reinforced with an onlay tendon graft (left-over from the EIP transfer). Outcomes were excellent. This is the first publication to discuss delayed repair of a combined EPB and APL injury and gives insights into the anatomical and biomechanical balance of the thumb extensors.