Immobilization of the mallet finger - Effects on the extensor tendon

Since the mallet finger that is treated with isolated splinting of the dist al interphalangeal (DIP) joint can be moved freely proximal to the DIP join t, we sought to determine whether such motion might cause a tendon gap that could explain the extensor lag that often follows treatment. Experiments w ere performed on 32 cadaveric fingers with open mallet finger lesions, immo bilizing either the DIP joint alone or both the DIP and PIP joints, while r epeatedly flexing and extending the more proximal finger and wrist joints. For each experiment, the gap in the extensor tendon was measured. Joint mot ion proximal to the DIP joint and retraction of the intrinsics did not caus e a tendon gap in a finger with a mallet lesion, supporting the convention that only the DIP joint needs to be immobilized.