Transplantation of amputated bony phalanges as a salvage thumb reconstruction method - a preliminary report.

BACKGROUND

Every traumatic amputation of the thumb is an indication for an attempt of replantation. Due to local state of the wound not every case qualifies for this procedure. Such patients may be offered a multi-step salvage reconstruction of the amputated finger; the first step consists of an emergency implantation of the bony phalanx under the skin of the abdominal wall. The osseous graft was covered with skin using a pedicled tubular flap or a "cutaneous pocket". The aim of this paper was to evaluate the effectiveness of this reconstructive method.

MATERIAL AND METHODS

Over a period of four years, we operated on 24 patients (22 males, 2 females) aged 17 - 56 years (mean 31.3 yrs); trauma affected the dominant hand in 16 cases (66%); 17 patients (71%) lost their thumbs at the level of IP joint ; in the remaining 7 cases (29%) the amputation was at the level of the MCP joint. In 3 cases with concomitant amputation of the 2nd and 3rd fingers, the grafted structure was the bony phalanx of the index finger. The grafted phalanx, its soft tissues pared off, was joined with the proximal phalanx or the 1st metacarpal bone with two K-wires and then covered with a pedicled tubular flap or implanted to a cutaneous pocket preformed from the abdominal wall. The flap and the "pocket" were cut away on average after 30.2 days. The cutaneous plasty of the finger was performed on average after 11.3 weeks; the sensory island was transferred according to Littler in 18 patients on average 22.2 weeks after the amputation. The evaluation included: osteosynthesis, mobility of the finger (Kapandji's test), pinch-grip strength, touch sensation (filament and discriminatory, temperature sensitivity), esthetics of the finger, and the employment status of the patients.

RESULTS

Failure of losing the graft occurred in 3 patients (12%) and was due to an infection unresponsive to treatment and developing on necrotic flaps. Five patients (21%) developed marginal necrosis within the fragments of the cut off flaps requiring cutaneous plasty; an inflammation of the recipient site occurred in 5 cases (21%). 18 patients (75%) of the patients turned up for the distant follow-up on average 13.2 months after the accident (range 11 - 28 mths). 16 patients (89%) had good bone union; in 2 cases the distal part of the graft had been resorbed. All of the patients were able to touch the pseudo-ball of the thumb with the 5th finger. The strength of the pinch-grip on average reached 3.3 kG (range 1.8 - 6.2 kG), which equals to 55% (range 36 - 78%) of the uninjured hand. Touch sensation was satisfactory in 16 patients (89%) (blue filament), reduced in 2 (11%); 6 patients (33%) showed two-point discrimination in the range of 10 to 15 mm. The esthetical result of the thumb was assessed as good in 13 (72%) and satisfactory in 5 patients (28%). Fifteen patients (83%), 9 blue collar workers and 6 farmers, continued with their occupations.

CONCLUSION

The autograft of the amputated phalanx is a valuable reconstructive method for a selected group of patients.