Femoral Lengthening Over a Pediatric Femoral Nail: Results and Complications

Background: Limb lengthening by callotasis as described by Ilizarov has become the standard method of lower extremity lengthening. Lengthening over an intramedullary nail to allow early removal of the external fixator has also become common in adults but few studies have addressed the efficacy in children. Methods: A retrospective review of 37 consecutive children who had undergone femoral lengthening with external fixator over an intramedullary nail was performed. Charts were reviewed for demographics, surgical details, and complications. Radiographs were examined to determine magnitude of lengthening and to calculate lengthening index. Results: The average age of the 37 patients was 11.6 years (range, 8.1 to 17.0). The amount of lengthening averaged 7.0 cm (range, 3.0 to 11.4 cm), which represented a mean 20.4% increase in length. The mean time in the fixator was 81 days. The lengthening index was 1.21 days/mm. Thirteen patients developed major complications (37.8%) including 4 limbs that failed to lengthen initially, 3 fractures (1 before fixator removal and 3 after fixator removal), 2 nail failures, 4 deep infections, and 2 joint subluxations requiring operative care. The 3 fractures after fixator removal were treated with exchange nailing as were the 2 intramedullary nail failures. Four patients (10.8%) developed deep infections requiring irrigation, debridement, and IV antibiotics. One patient developed a late hip subluxation, which was treated with a shelf osteotomy but resulted in pain and limitation of motion. One patient developed knee subluxation during lengthening requiring operative intervention. The technique was successful in obtaining a good result with a functional lengthened femur without unresolved problems in 94% of the patients despite a significant rate of major complications, particularly in those with a congenital etiology. Only 2 of the 37 patients ultimately had results that were ultimately compromised by complications. Conclusions: Femoral lengthening over an intramedullary nail with the aid of an external fixator has shown to be an effective method for correcting limb length discrepancy. The technique has a high complication rate similar to other methods of lengthening.