Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Surgery, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.
Department of Statistics, National Taipei University, Taipei, Taiwan, ROC; Department of Orthopedic Surgery, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan, ROC.
J Chin Med Assoc. 2017 Sep;80(9):587-594. doi: 10.1016/j.jcma.2017.04.007.
Cut-out failure is one of the most common complications in the Gamma3 nail fixation system. The purpose of this retrospective study was to determine pre-operative or intra-operative risk factors for cut-out failure of lag screws in unstable, intertrochanteric fractures fixed with short Gamma3 nails.
One hundred and seventy-six patients over 60 years of age, with unstable intertrochanteric fractures (AO/OTA 31-A2, 31-A3) treated with short Gamma3 nails were included in this study. All patients completed a minimum of 1-year follow-up. Analysis of post-operative radiographs included assessment for cut-out failure of lag screw, appropriateness of the entry point, posterior lag screw axis, fracture gaps, posterior displacement of the proximal fragment, and tip-apex distance.
Of the 176 patients in this study, 22 patients were identified with cut-out failure. Multivariate logistic regression analysis revealed that improper entry point in an antero-posterior projection (odds ratio 10.39, 95% confidence interval 1.74-78.4), posterior displacement distance of the proximal fragment in a lateral projection (odds ratio 1.35, 95% confidence interval 1.17-1.59), and female sex (odds ratio 17.14, 95% confidence interval 1.88-876.11) were correlated with cut-out failure.
This study emphasizes the importance of an optimal position of reduction in the lateral projection in reducing the risk of cut-out failure. In addition, sex difference in bone mineral density, proximal femur geometry, and the bone strength in elderly females may explain why female sex is a risk factor.
切割失败是 Gamma3 钉固定系统中最常见的并发症之一。本回顾性研究的目的是确定使用短 Gamma3 钉固定不稳定型股骨转子间骨折时，拉力螺钉切割失败的术前或术中危险因素。
本研究纳入了 176 名 60 岁以上的不稳定型股骨转子间骨折（AO/OTA 31-A2、31-A3）患者，采用短 Gamma3 钉治疗。所有患者均完成了至少 1 年的随访。术后 X 线片分析包括评估拉力螺钉切割失败、进钉点是否合适、后拉力螺钉轴、骨折间隙、近端骨块后移位以及尖端顶点距离。
在这项研究的 176 名患者中，有 22 名患者被确定为切割失败。多变量逻辑回归分析显示，前后位投影中进钉点不当（比值比 10.39，95%置信区间 1.74-78.4）、侧位投影中近端骨块后移位距离（比值比 1.35，95%置信区间 1.17-1.59）和女性（比值比 17.14，95%置信区间 1.88-876.11）与切割失败相关。
本研究强调了在减少切割失败风险方面，侧位投影中获得良好复位的重要性。此外，老年女性的骨密度、股骨近端几何形状和骨强度方面的性别差异可能解释了为什么女性是一个危险因素。
