BACKGROUND Intramedullary hip nails may be classified as blades or screws depending on the type of lag screw used. Recently, a combination of lag screw types with a U-clip insertion has also been used. The purpose of this study was to evaluate the clinical and radiological outcomes of these new screw types. METHODS A total of 185 patients with trochanteric femoral fractures (age ≥ 65 years) who underwent surgery with intramedullary nails were selected. Surgeries with InterTrochanteric/SubTrochanteric (ITST), Proximal Femoral Nail Antirotation (PFNA), and Gamma 3 U-Blade lag screws were performed between January 2011 and June 2016. The AO/OTA classification, presence of a basicervical fracture type on 3D-CT, BMI, BMD, reduction quality, position of the lag screw, TAD (tip apex distance) of the lag screw, sliding distance of the lag screw, varus change (neck shaft angle), radiological union period, fixation failure and functional outcome as determined by walking ability were analyzed. RESULTS There were 3/60 (5.0%) cases of fixation failure in the ITST group, all caused by cut-out; 4/57 (7.0%) in the PFNA II group: 3 caused by cut-through and 1 by metal fracture; 1/68 (1.5%) in the Gamma 3 U-Blade lag screw group (P = 0.301). In each group, the sliding distance of the lag screw showed a significant difference (P = 0.017), whereas significant sliding over 10 mm showed no statistically significant results. CONCLUSION There was only one (1.5%) case of fixation failure in the Gamma 3 U-Blade lag screw group. The sliding distance of the U-Blade was found to be in the middle, between the PFNA II (shorter) and ITST (longer) implants. The new rotational control lag screw seems to be comparable to other screw types.

中文翻译：

---

股骨转子骨骨折患者的Gamma 3 U型刀片拉力螺钉：旋转控制拉力螺钉是否比其他更好？

背景技术根据所使用的方头螺钉的类型，髓内髋部钉可分类为刀片或螺钉。最近，还使用了方头螺钉类型与U型夹插入的组合。这项研究的目的是评估这些新型螺钉的临床和放射学结果。方法选择185例年龄≥65岁的股骨转子粗隆骨折患者，均采用髓内钉进行手术。在2011年1月至2016年6月之间进行了穿刺入/次入穿刺（ITST），股骨近端防旋转（PFNA）和Gamma 3 U型刀片拉力螺钉的手术。AO / OTA分类，在3D-CT上存在基本神经型骨折类型，BMI，BMD，减速质量，方头螺钉的位置，方头螺钉的TAD（尖端顶点距离），方头螺钉的滑动距离，分析步行能力决定的内翻变化（颈轴角度），放射学结合期，固定失败和功能结局。结果ITST组有3/60（5.0％）的固定失败病例，全部是由切开术引起的。PFNA II组中的4/57（7.0％）：3是由直通引起的，1是由金属断裂引起的；Gamma 3 U型刀片方头螺钉组中的1/68（1.5％）（P = 0.301）。在每组中，方头螺钉的滑动距离均显示出显着差异（P = 0.017），而在10 mm以上的滑动均无统计学意义。结论Gamma 3 U型刀片方头螺钉组中只有1例（1.5％）发生固定失败。发现U型刀片的滑动距离在PFNA II（较短）和ITST（较长）植入物之间。