This case report illustrates the use of distraction lengthening as described by Ilizarov in achieving restoration of functional length in a replanted thumb. The patient suffered a table saw amputation of the thumb and index fingers at the MCP joint level. The index was determined to be non-viable and a ray amputation was performed. A standard replantation of the thumb through the MCP joint was performed, with shortening of the proximal phalanx and arthrodesis at the level of the joint. The replantation was uncomplicated, but function was hindered by excessive loss of length and absence of flexion angulation at the arthodesis site. Therefore, distraction lengthening was performed, beginning at 9 months after the replantation. An osteotomy was made at the level of the arthrodesis, and a mini-external fixator was applied. Lengthening was performed by the patient at a rate of 1 mm/day. Following lengthening of 2cm, the gap was grafted with a cortical allograft as an onlay over the regenerated bone, and fixed with a dorsal plate. Post-operative function was improved, and the patient regained functional grasp and pinch with the lengthened thumb.
Distraction lengthening has been applied successfully to post-traumatic and post-surgical limb length deficits in the long bones with great success. It has been applied less frequently, and reported infrequently, in the hand. Nonetheless, the principles remain the same, and the technique clearly has applications to both traumatic and non-traumatic defects in the digits; this is especially true in thumb, where adequate physiologic length is so critical for prehension. In replantation, where shortening of the part is often necessary to achieve successful replantation outside the zone of injury, the technique offers great potential benefit to patients surviving their injury with the best possible functional outcome.
Journal of Reconstructive Microsurgery