Reconstruction of Amputated Thumb through Lengthening of First Metacarpal

Abstract

Objective

Restoration and/or improvement of pinch and grasp through elongation of the first metacarpal and deepening of the first web space.

Indications

Functional limitation of thumb, in particular of pinch and grasp after traumatic amputation in zone 2 according to Strickland & Kleinman.

Contraindications

Inadequate skin and soft tissue coverage of amputation stump.

Absence of sensation over stump.

Osteoarthritis of trapezometacarpal joint.

Osteoporosis.

Insufficient compliance and lack of comprehension by patient.

Surgical Technique

First step: placement of unilateral minifixateur. Posteroradial incision and osteotomy of the first metacarpal.

Phase of distraction: continuous distraction starting on day 7, 1 mm per day.

Second step: once the desired length has been reached, bridging of the distraction callus with a miniplate and deepening and enlargement of first web space using a local skin flap.

Results

Between 1998 and 2000, ten patients (nine men, one woman, aged between 15 and 68 years) were treated. The amputation occurred four times in zone 2a and six times in zone 2b. An isolated injury to the thumb was seen nine times, and once one of the other fingers was involved. The desired gain in length was reached in nine patients, it amounted to 31 mm (25–35 mm). Strength of pinch improved by an average of 45% and that of grasp by 55%.