The effect of flexor digitorum profundus tendon shortening on jersey finger surgical repair: a cadaveric biomechanical study

Delayed diagnosis of jersey finger injuries often results in retraction of the flexor digitorum profundus tendon. Current practice recommends limiting tendon advancement to 1 cm in delayed repairs. The purpose of this study was to investigate the biomechanical consequences of tendon shortening on the force required to form a fist. The flexor digitorum profundus muscle was isolated in ten cadaveric forearms and the force required to form a fist was recorded. Simulated jersey finger injuries to the ring finger were then created and repaired. The forces required to pull the fingertips to the palm after serial tendon advancements were measured. There was a near linear increase in the force required for making a fist with shortening up to 2.5 cm. The force required to make a fist should be taken into account when considering the limit of 'safe' tendon shortening in delayed repair of jersey finger injuries.