[Application of Ilizarov technique in functional reconstruction of thumb degloving injury after amputation].

Objective: To investigate the effectiveness of Ilizarov technique in reconstruction of thumb function in patients with thumb degloving injury after amputation.

Methods: Between June 2011 and September 2016, 9 cases of thumb degloving injury were treated with amputation and Ilizarov technology. There were 8 males and 1 female with an age of 18-52 years (mean, 34.7 years). The amputation plane was the level of the metacarpophalangeal joint in 5 cases, the level of the proximal metacarpophalangeal joint in 2 cases, and the level of the base of the proximal phalanx in 2 cases (the length of proximal phalanx was less than 1 cm). After amputation, the affected finger was shorter than the healthy finger by 4.0-7.5 cm, with an average of 5.7 cm. On the fifth day after operation, the semi-loop external fixation extender was applied for extension, which was extended by 0.5 mm per day, and was extended once every 6 hours.

Results: After bone lengthening surgery, the first web space elevation and contracture occurred in 8 cases. Six of them were treated with the amputation of the inner muscle of the thumb and the "Z" forming technique, postoperative thumb function recovered well; the remaining 2 cases rejected plasty. All 9 patients were followed up 14-47 months, with an average of 33 months. Bone lengthening time was 64-122 days, with an average of 86 days. The lengthening length of bone was 3.0-5.9 cm, with an average of 4.1 cm, and the average lengthening length was 71.9% of the average shortened length. The fixation time of external fixator was 169-342 days, with an average of 231 days. The healing index was 43.2-59.1 days/cm, with an average of 53.4 days/cm. One case showed prolonged mineralization delay and recovered after "accordion" treatment. Bone healing was finally achieved in all patients, with the healing time ranging from 169 to 342 days, with an average of 231 days. No replantation internal fixation and flexion contracture occurred. The two-point discrimination of extended fingertip was similar to that of normal fingertip. The grip strength reached 53%-89% of the healthy side; the kneading force reached 59%-91% of the healthy side.

Conclusion: The application of Ilizarov technology to extend the thumb metacarpal lengthening is a good method to reconstruction the thumb function after degloving injury.