Introduction: Aim of this retrospective study was to obtain a functional outcome following callus distraction and phalangization of the thumb after traumatic amputation in the middle one-third.
Materials and methods: From January 1998 to June 2001, 12 patients were treated in a staged procedure starting with corticotomy and continuous distraction (1 mm/day) of the first metacarpal bone using a unilateral external fixator device. After distraction until day 31 (range 25-35 days), the first metacarpal bone was stabilized with a plate, and phalangization was performed. RESULTS. At follow-up 1 year after surgery, the thumb was lengthened to 25-35 mm (average 28 mm) in all but 1 patient. In 1 patient a bone graft from the iliac crest had to be interposed. Pinch grip improved by 45%; grip strength improved by 55%. The function/symptom score from the DASH questionnaire was 25 points (range 16-38 points). In a 'pick-up test' all patients were able to pick up a pencil, they were able to write and could hold a full cup of water. Nine patients were able to pick up a paper clip, and 8 patients could hold a 1-liter bottle of water.
Conclusion: Callus distraction can be considered a suitable procedure to reconstruct an amputated thumb levelled at the middle one-third. Additional phalangization proved essential as it deepened the first web space, enabling good motion and grasp. Callus formation was delayed in elderly patients, but adequate lengthening and bone healing also occurred in this age group. The procedure will not be as beneficial in cases of osteoarthritis of the trapezometacarpal joint or when coverage of the stump is insufficient. The DASH questionnaire is very helpful in evaluating the effect of thumb reconstruction on the entire upper limb.