Migration of the Lag Screw after Intramedullary Treatment of AO/OTA 31.A2.1-3 Pertrochanteric Fractures Does Not Result in Higher Incidence of Cut-Outs, Regardless of Which Implant Was Used: A Comparison of Gamma Nail with and without U-Blade (RC) Lag Screw and Proximal Femur Nail Antirotation (PFNA)

Abstract

The best intramedullary nail for the treatment of unstable AO/OTA 31.A2.1-3 fractures remains uncertain. A total of 237 patients (45 male, 192 female) were eligible for the assessment with an average age of 81.9 ± 10.5 years and a minimum follow-up of six months. We assessed the cut-out rate, the TAD and calTAD (Tip Apex distance) of three different implants. An overall cut-out rate of 2.5% (n = 6) was observed. The cut-out rate was 1.2% (n = 1) in the Proximal Femur Nail Antirotation (PFNA) group, 3.7% (n = 3) in the Gamma Nail group and 2.9% (n = 2) in the Gamma3® with a U-Blade (RC) lag-screw group. The TAD and calTAD differed between the cut-out and non-cut group—20.0 mm vs. 18.5 mm and 13.1 mm vs. 15.3 mm, respectively. A significantly higher TAD of 32.5 mm could be seen in the cut-out after PFNA (p < 0.0001). The only significant change in follow-up using Parker’s ratio was observed in the PFNA group (p < 0.0001). The rate of patients requiring surgery after complications was 8.4% (n = 20) without any significant difference between the three groups. The PFNA blade showed significant migration within the femoral head, however the cut-out rate remained the smallest compared to Gamma3 with or without additional U-Blade (RC) lag screw.

Keywords

• AO/OTA 31.A2.1-3 femur fractures
• cut-out
• Proximal Femur Nail Antirotation (PFNA)
• Gamma Nail
• U-Blade RC lag-screw