Use of magnetic growing intramedullary nails in compression during intercalary allograft reconstruction

Abstract

Traditionally, intercalary allograft reconstruction after tumor resection has had a high rate of complications, particularly nonunion. Plate and intramedullary nail fixation have been used alone and in combination to improve union rates. This study sought to evaluate a new technique that uses a magnetic growing intramedullary nail to compress the osteotomy sites to aid in healing and to answer 2 questions: (1) What is the union rate and the time to union when using magnetic growing intramedullary nails? (2) What complications occur with this technique? Eight patients with 15 osteotomy sites with a minimum follow-up of 14 months were retrospectively reviewed. Seven of the 8 patients underwent initial reconstruction with the magnetic nail, whereas 1 patient underwent treatment of a nonunion that occurred with prior carbon fiber nail fixation. Twelve of the 15 osteotomy sites had healed by an average of 9 months. Nonunions occurred in 2 patients with an associated failure of the hardware. One of these patients healed after revision surgery. Of the patients who healed at both sites, 1 had a fracture through the allograft, 1 had backing out of a locking screw that required removal, and 1 required a manipulation under anesthesia of the knee. Two patients underwent successful limb lengthening needed because of an expected limb-length discrepancy after healing occurred. Use of growing intramedullary nails in compression mode led to an 87% union rate at final follow-up with acceptable complications. This technique provides a viable alternative to standard nail and plate fixation when intercalary allografts are used.