Intramedullary Nailing for Atypical Femoral Fracture With Lateral Bowing: Does Medial Gap Matter?

Abstract

Introduction When performing intramedullary nailing for atypical femoral fractures (AFF), especially in lateral bowing femurs, a medial opening wedge-shaped gap in the fracture site may occur after nailing. We intended to analyse and compare clinical outcomes according to the medial gap in AFF cases after intramedullary nailing. Materials and Methods: Of the 38 consecutive patients with complete AFF treated by intramedullary nailing, 22 patients (all female, mean age of 76.5 years [range, 62–87]) available for follow-up for more than 12 months were included. According to the size of the medial gap, the patients were divided into 2 groups: large and small medial gaps. Comparative analysis was performed between groups in terms of patient, fracture characteristics and post-operative clinical outcomes. Results: There was no significant difference in bone union time between the 2 groups (5.4 months vs 5.6 months, P = .628). When comparing the amount of change in the hip–knee–ankle angle after the surgery with reference to the contralateral side, there was a significant difference between the 2 groups (−4.4° [femoral straightening and relatively changed to a more valgus pattern, that is, in cases of varus alignment, towards neutral alignment] vs .5°, P = .002). There was no significant difference in leg length discrepancy between the 2 groups (4.1 mm vs 3.2 mm, P = .674). In terms of functional outcomes, there was no significant difference in the recovery of ambulatory ability (ΔKoval grade: post-operative Koval grade–pre-operative Koval grade, 0 vs .1, P = .771). Conclusion: Even if the medial gap occurs following intramedullary nailing in AFF, post-operative clinical outcomes seem to be acceptable. However, if previous total knee arthroplasty is performed and neutral alignment is maintained, care should be taken as the occurrence of the gap may result in lower limb malalignments.