Femoral lengthening over elastic stable intramedullary nailing in children using the monolateral external fixator

The authors report preliminary results of femoral lengthening performed with monolateral external fixation over elastic stable intramedullary nailing in children. Seven femoral lengthenings were performed in six patients, at a mean age at surgery of 6.6 years (range 1.5-12 years). All lengthenings were performed due to limb length discrepancy (congenital hypoplasia in four patients, growth arrest secondary to neonatal infective osteoarthritis in one, type II sacral agenesis in one). In six cases the elastic nails realised a bipolar ascending construct, in one case a descending construct. Cases were reviewed at a mean time from removal of external fixator of 34.2 months (range 15-75 months). The mean lengthening obtained was 4.8 cm (range 3.8-6.0 cm). Mean consolidation index was 42.9 days/cm. No case of axial deviation requiring surgery and no case of deep infection were recorded. No case of fracture of the regenerate occurred after removal of the external fixator. There were two premature consolidations requiring mobilisation under general anaesthesia, and a case of failure of consolidation requiring surgery. The technique reported provides indisputable biomechanical advantages, particularly increasing stability at the site of osteotomy. The characteristics of implants make this method ideal for lengthenings in children.