11 Extensor Indicis Proprius to Extensor Digitorum Communis Tendon Transfer
Transfer of the extensor indicis proprius (EIP) to the extensor digitorum communis (EDC) tendons can restore finger extension for ruptured tendons. The EDC tendons, especially those of the lesser digits, most commonly rupture from attritional wear due to chronic inflammatory changes from distal radioulnar joint arthritis. Tendon transfer principles are applied, including an expendable donor, synergistic function, similar excursion and power, straight line of pull, and one transfer for one function—thumb extension. Proper tensioning of the transfer is important, with slight over-tensioning preferable. A Pulvertaft or similar tendon weave should provide adequate repair strength to start therapy early in the postoperative period. Addressing the degenerative changes in the distal radioulnar joint is critical to prevent re-rupture.
Transfer of the extensor indicis proprius (EIP) tendon to the extensor digitorum communis (EDC) tendon is an in-phase tendon transfer for the treatment of chronic or attritional ruptures of the EDC tendons to the middle, ring, or small fingers.
11.2 Key Principles
When considering tendon transfers for the upper extremity, various factors should be considered. The finger joints should be supple and the soft tissue bed should be adequate enough to allow for tendon gliding. When selecting a tendon for transfer, one should consider if the tendon for transfer is expendable, what is the strength of the muscle tendon unit, and if there is a straight line of pull. When the rupture is caused by inflammatory changes in the distal radioulnar joint, addressing the degenerative changes in the distal radioulnar joint is critical to prevent re-rupture.
Good-to-excellent results can be achieved with proper execution of the tendon transfer. Patients can expect to achieve good digital extension after surgery and appropriate hand therapy, although some weakness in finger extension and a slight extensor lag are often seen.
EIP to EDC tendon transfer should be considered for patients with a single chronic digital extensor tendon rupture.
Stiff finger joints
Soft tissue envelope that would not allow for tendon gliding
Lack of EIP tendon for transfer
Multiple tendon ruptures
Cognitive impairment that would adversely affect the patient’s ability to participate in occupational therapy