Abstract
Introduction: Lengthening for congenital femoral hypoplasia is associated with a significant refracture rate and problems in recovery of knee motion. We present a series of 7 patients where two techniques of lengthening were used and recovery of knee motion compared.
Methods: This is a retrospective study. The outcome of interest was recovery of knee motion. All children were diagnosed to have congenital femoral hypoplasia. In two patients (group A), conventional metaphyseal osteotomies of the femur and tibia, with ankle and knee bridging fixators were applied. In the remaining five (group B), a combination of soft tissue releases, patella ‘capture’, a modified external fixator configuration and early conversion to internal fixation was used. Osteotomies of tibia and femur were performed in the mid-shaft and lengthening progressed at 0.75 mm per day. At 4 months, before regenerate consolidation, both femur and tibia were plated using a submuscular technique. The limb was supported in a cast, which was replaced by a brace at 3 weeks and knee motion exercises started. Lengthening was kept to within 15% in both groups.
Results: Recovery in knee flexion to greater than 90 degrees was accomplished by 4 of the 5 Group B patients by 4 months. One patient failed to attend for physiotherapy and did not progress with knee motion recovery. One patient sustained a fracture proximal to the submuscular plate which needed revision surgery. This did not hinder progress with knee motion recovery. In comparison, patients in group A reached 90 degrees of flexion at 12 months with one patient not exceeding 85 degrees at final follow up and subsequently needing a quadricepsplasty.
Conclusion: Recovery of knee motion may be assisted by soft tissue releases in combination with early conversion to internal fixation.
Correspondence should be addressed to BLRS c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
