Locked plating for internal fixation of the adult distal femur: influence of the type of construct and hardware on the clinical and radiological outcomes.

INTRODUCTION: Distal femoral fractures are rare and serious. Along with traditional internal fixation, new, dedicated hardware have appeared (distal nails, locked plating). We report the results of a multicenter prospective study of these fractures treated with locked plating.

HYPOTHESIS: The short-term results are satisfactory and related to the type of construct and the hardware used, with better results for elastic assemblies and titanium implants.

MATERIALS AND METHODS: From June 2011 to May 2012, 92 patients, mean age 64 years, were included in 12 centres. The fractures were classified as follows: 44 type A, 7 type B, and 41 type C according to the AO classification. Thirteen fractures were open. The plates were uniaxial. The assemblies were elastic in 52 cases, rigid in 26, and unconventional in 14.

RESULTS: Seventy-six patients underwent a radiological follow-up at 6 months and 66 patients had a clinical result evaluated at 1 year. The mean range of motion was 100° and the mean IKS score was 122. The bone union rate was 87% within 12 weeks. Seven valgus, two varus, ten flexion deformities, and three recurvatum greater than 5° were observed (19.5%). Revisions involved two cases with loss of fixation, five cases of infection, and one case of arthrofibrosis (requiring arthroscopic arthrolysis). Secondary bone grafting was carried out in seven cases (four successfully). No influence of the type of assembly or the hardware used was demonstrated.

DISCUSSION: The results remain modest, underscoring the severity of these fractures. Neither the type of construct nor the hardware used influenced the radiological and clinical outcomes. The hypothesis was not confirmed.

LEVEL OF EVIDENCE: Level IV prospective, non-comparative study.