Combined antegrade femur lengthening and distal deformity correction: a case series

Abstract

Background: Leg length discrepancy is often associated with distal femur angular deformities such as valgus or flexion. This study aims to report a new technique for simultaneous limb lengthening and acute distal femoral angular correction.

Methods: A retrospective chart review of patients undergoing a single procedure was conducted. Patients included had a single operation where they underwent distal femur osteotomy stabilized with a plate followed by antegrade nailing with a magnetically controlled intramedullary lengthening nail (PRECICE, Ellipse Technologies, Inc., Irvine, CA, USA) using a trochanteric entry.

Results: Seven femurs from 7 patients were included. The average age at operation was 13.6 years, and the leg length difference was 51 mm (range 30-105 mm). Associated deformities were valgus (4), knee flexion contracture (2), and both valgus and flexion contracture (1). Lengthening achieved was 43 mm (P = 0.0036), with a consolidation index of 27 days/cm and reliability of 0.87 (6/7). The 5 patients with angulation had an improvement of valgus from 12 to 4° (P = 0.006) and of the mechanical axis deviation from 34 to 3 mm (P = 0.0001). The range of motion also improved in the 3 patients with contractures. Preoperative gait disturbance, hip and knee pain, and functional scoliosis resolved after the limb deformities were corrected.

Conclusion: Combining a magnetic internal lengthening nail with a second distal osteotomy stabilized with a plate can successfully correct limb length and distal femur deformity acutely without altering the expected result of each procedure.

Keywords: Combined femoral deformities; Leg length discrepancy; Limb lengthening; Magnetic intramedullary nailing; PRECICE nail; Two-level osteotomy.

Fig. 1

Intraoperative fluoroscopy demonstrates a stable distal femur osteotomy and b functioning lengthening nail with adequate distraction

Fig. 2

X-ray at a follow-up visit demonstrates interval lengthening and good alignment of the weight-bearing axis

Fig. 3

Patient with an acquired leg length discrepancy and 2 prior lengthening operations for his right femur. a Right femur shortening and valgus deformity preoperatively. Patient is standing on a 6-cm block. b Significant improvement of both deformities at final follow-up