目的　研究PFNA内固定治疗老年骨质疏松性股骨转子间骨折术后股骨近端几何结构参数值的变化。  方法　选取老年骨质疏松性股骨转子间骨折患者36 例，分别在术后即刻与术后1.5~2年的骨盆平片上测量股骨近端几何参数（包括顶高距、偏心距、近端长度、颈干角），比较其术后即刻与骨折愈合后股骨近端形态学变化。   结果　患者术后即刻与骨折愈合后几何参数比较，术后1.5~2年所测量顶高距、偏心距、近端长度及颈干角均较术后即刻有不同程度的变小，其中顶高距变化值为(1.25±0.94)mm,偏心距的变化大小为(0.36±1.13)mm，近端长度变化大小为(3.25±3.06)mm，颈干角变化大小为(0.22±0.76)°，术后即刻与术后1.5-2年的资料比较，除顶高距、近端长度外（P＜0.05），其余项目比较差异无显著性（P＞0.05）。   结论　应用PFNA治疗老年骨质疏松性股骨转子间骨折，在骨折愈合过程中，经股骨颈传导的应力作用导致近端受力解剖结构参数不同程度变小,可接受的几何结构变化值有助于维持内固定系统的整体稳定性，有利于骨折的愈合。

Objective　To explore the change of proximal femur geometry parameters in old osteoporotic intertrochanteric femoral fracture healing process managed by PFNA.　Methods　Thirty-six old patients with osteoporotic intertrochanteric femoral fracture were chosen. The proximal femur geometric parameters, including top-high-pitch, offset, proximal length, neck-shaft angle, were measured after operation immediately and 1.5 to 2 years after surgical treatments.　Results　After operation, the geometric parameters became smaller, including top-high-pitch being (1.25±0.94) mm, offset (0.36±1.13) mm, proximal length (3.25±3.06) mm, neck-shaft angle (0.22±0.76)°. The proximal length and top-high-pitch were significantly lower (P＜0.05). The other changes were not significant (P＞0.05).　Conclusion　Using PFNA to manage the old osteoporotic intertrochanteric femoral fracture, enables the force to pass through the femoral neck during the fracture healing process, resulting in proximal anatomical structure parameters becoming smaller in different degree. Moreover, acceptable geometric changes contribute to the overall stability of the internal fixation system, which can be helpful to the healing of the fracture.