尖顶距与股距尖顶距的研究进展

Tip-apex distance and calcar-referenced tip-apex distance used as a predictor of screws cutout from the femoral head

股骨转子间骨折是骨科常见疾病，其中不稳定型骨折需要手术治疗。术中尖顶距作为衡量股骨头内拉力螺钉位置是否合适的标准，已经被医生认识并接受。自尖顶距的概念提出以来，其在临床上得到了广泛应用，甚至作为判断螺旋刀片在股骨头内位置的标准，但拉力螺钉与螺旋刀片的尖顶距是否一致仍存争议。同时尖顶距的缺陷已有文献报道，为此国外有学者提出了“股距尖顶距”的概念。本文对尖顶距和股距尖顶距的概念和临床应用进展进行综述。

Intertrochanteric fracture, a common kind of injury in orthopaedic surgery, often requires surgical intervention, especially the unstable ones. Since far back in 1995, Baumgaertner et al. recommended using the distance between the screw tip and femoral head apex （tip-apex distance, TAD） as a predictor of the risk of lag screw cutout, the importance of TAD has been recognized by orthopaedic surgeons. This concept has been widely accepted in practice, and even used as a standard in determining the helical blade position. It is not clear, however, whether the helical blade system is equal to lag screws in terms of TAD. After the limitations of TAD had been reported, Kuzyk et al. proposed a tip-apex distance referenced from the calcar （Cal-TAD） as a predictor of lag screw cutout to improve the concept further. In this article, these concepts and the latest clinical applications of TAD and Cal-TAD are reviewed based on the publications available.