Gamma 3 vs Gamma 3 RC in Unstable Extracapsular Hip Fractures: A Prospective Randomized study

Rotational instability is a key factor in fixation failure of extracapsular hip fractures. The U-Blade (RC) lag screw was designed to improve rotational stability. This study aimed to compare mechanical complication rates between Gamma3 and Gamma3 RC nails in elderly patients with rotationally unstable extracapsular fractures.

We conducted a prospective, single-center randomized controlled trial including 316 patients aged ≥ 65 years with rotationally unstable extracapsular fractures. Patients were randomized to treatment with a Gamma3 nail (n = 169) or a Gamma3 RC nail (n = 147). Mechanical complications were classified as major (rotation and migration of the implant, cut-out, non-union) or minor (back-out, cervicodiaphyseal angle change, excessive sliding).

The overall rate of major complications was 2.9 per 10,000 person-days, being the most frequent the cut out (2.2%), with no significant difference between Gamma3 and Gamma3 RC groups (RR = 1.0; 95% CI: 0.4-2.7). TAD > 25 mm increased the risk of major complications (RT = 3.7; 95% CI: 1.2-11.2), as did superior screw placement (Cleveland zones 1-3: RT = 7.5; 95% CI: 2.7-20.8) and postoperative diastasis (RT = 4.7; 95% CI: 1.4-16.2). Similarly, implant type was not significantly associated with minor complications that were observed in 85 patients (26.9%), most frequently back-out (14.6%).

The U-Blade (RC) lag screw did not reduce mechanical complication rates compared with the standard Gamma3. Radiographic parameters, particularly TAD, reduction quality, screw position, and postoperative diastasis, were the main predictors of fixation failure.