Outcomes of U-Blade Lag Screw for Cephalomedullary Fixation of Unstable Trochanteric Femur Fractures: A Case Control Study.

Background: Unstable trochanteric femur fractures in elderly patients with osteoporosis are still challenging. Gamma3 nail with the U-blade lag screw (U-blade gamma nail) has been developed to improve mechanical stability of proximal femoral fragment. This study aimed to compare the clinical and radiologic outcomes of U-blade gamma nail to proximal femoral nail antirotation (PFNA), and standard Gamma3 nail (gamma nail) for unstable trochanteric femur fractures.

Methods: A retrospective matched-pair case study was performed with U-blade gamma nail, PFNA, and gamma nail. During 2012-2018, 970 patients with unstable trochanteric femur fractures were reviewed. Matching criteria were set as follows: 1) sex; 2) age (± 3 years); 3) body mass index (± 2 kg/m); 4) bone mineral density (± 1 T-score in femur neck). Finally, a total of 159 patients were enrolled. We assessed the tip-apex distance (TAD), neck shaft angle, and hip screw sliding distance using plain radiographs. Also, we evaluated the clinical outcomes with Koval's grade and fixation failure during 2 years.

Results: The mean postoperative TAD was not significantly different among the 3 groups (p = 0.519). However, the change in the TAD at 1 year (p = 0.027) and 2 years (p = 0.008) after surgery was significantly smaller in U-blade gamma nail group compared with PFNA and gamma nail group. The hip screw sliding distance at 1 year (p = 0.004) and 2 years (p = 0.001) after surgery was significantly smaller in U-blade gamma nail group compared with PFNA and gamma nail group. However, there was no significant difference of Koval's grade and fixation failure among the 3 groups (p = 0.535).

Conclusion: U-blade gamma nail showed favorable radiologic results in terms of the change in the hip screw position. However, U-blade gamma nail was not superior to PFNA and gamma nail in clinical outcomes.