Outcomes of length-stable fixation of femoral neck fractures.

INTRODUCTION

The most common implants for treating unstable femoral neck fractures are sliding constructs, which allow postoperative collapse. Successful healing, typically, is a malunion with a shortened femoral neck. Functional sequelae resulting from altered femoral neck biomechanics have been increasingly reported. Re-operation rate due to nonunion, avascular necrosis, hardware cut-out and prominence is high with this treatment modality. We evaluated the outcomes of patients with femoral neck fractures treated with stable calcar pivot reduction, intraoperative compression across the fracture, and stabilization with length-stable implants.

MATERIALS AND

METHODS

Fifty-four patients with femoral neck fractures underwent open reduction and internal fixation. Average follow up duration was 23.6 months (range: 15-36 months). There were 23 Garden I, 2 Garden II, 14 Garden III and 15 Garden IV fractures. Reduction was achieved through a modified Smith-Petersen approach. Fractures were compressed initially, and subsequently stabilized with a length-stable device. Post-operative radiographs were assessed for change in fracture alignment. Variation in the femoral neck offset and abductor lever arm measurements was performed using the contralateral hip as control. Functional outcome was assessed using SF-36, Harris Hip Score (HHS) and a gait analysis device. The average patient age was 78 years. Fifty-one (94%) healed without complications. Surgical fixation failed in two patients and one patient developed avascular necrosis. The average femoral neck shortening was 1.7 mm.

RESULTS

The average difference in femoral neck offset and the abductor lever arm measurement at the latest follow up was 3.5 and 1.5 mm respectively. The average score on physical, mental components of SF-36 and HHS was 42 and 47 and 87 respectively. By 6 months, patients on average recovered 94% of the single limb stance time, 98% of cadence, 90% of cycle duration, 96% in stride length compared to the uninjured side.

CONCLUSION

Reduction with a stable calcar pivot, intraoperative compression and length-stable fixation can achieve high union rates with minimal femoral neck shortening and improved functional outcomes.

LEVEL OF EVIDENCE: IV, retrospective with historical controls.