模拟增强型PFNA和联合加压交锁髓内钉Intertan治疗骨质疏松老年反粗隆间骨折的生物力学性能并比较其优劣。

采用有限元分析法分别建立增强型PFNA和Intertan固定股骨粗隆间骨折（AO分型31~A3.1型）模型，比较2种模型内植物与股骨的总应力分布、应力峰值及位移。

两组内固定等效应力均主要分布与主钉内侧，增强型PFNA组最大等效应力位于主钉与远端螺钉交界处，为192.76 Mpa，Intertan组最大等效应力位于联合交锁钉与拉力螺钉交界处，为395.87；（2）增强型PFNA组与Intertan组均发生了不同程度的位移，最大位置均位于股骨头，并逐渐向远端见效，两股骨头处的位移峰值分别为:增强型PFNA组：4.562 mm，Intertan组：4.68 mm。

两组内固定物的最大等效应力均位于髓内钉上，并远大于股骨上承担的应力，说明在两组内固定对于股骨粗隆间骨折均是有效的，在术后早期内固定物承担最大的应力，缓解了股骨上的应力，有利于骨折愈合，但增强型PFNA组的最大等效应力较小，相对Intertan组更加稳定，减少了出现内固定失效的风险。使用增强型PFNA固定时，股骨承担的应力更小，能起到更好的支撑作用。因此增强型PFNA是老年骨质疏松性反粗隆间骨折的更佳选择。

To simulate the biomechanical properties of enhanced PFNA and compression interlocking intramedullary nail Intertan in the treatment of elderly anti-trochanteric fractures with osteoporosis.

Three-dimensional finite element method was used to establish the model of enhanced PFNA and Intertan fixation for intertrochanteric fracture (AO classification 3.1). The total stress distribution, peak stress and displacement of the two models were compared.

The equivalent stress of internal fixation in both groups was mainly distributed on the medial side of the main screw. The maximum equivalent stress in the enhanced PFNA group was located at the junction of the main screw and the distal screw, which was 192.76 Mpa, while the maximum equivalent stress in the Intertan group was located at the junction of the oblique screw and the lag screw, which was 395.87; (2) Both the enhanced PFNA group and the Intertan group had different degrees of displacement. The maximum position was located in the femoral head and gradually took effect to the distal end. The peak displacement of the two femoral heads was 4.562 mm in the enhanced PFNA group and 4.68 mm in the Intertan group.

The maximum equivalent stress of the internal fixation in both groups is located on the intramedullary nail, and is far greater than the stress borne on the femur, which indicates that the internal fixation in both groups is effective for the intertrochanteric fracture of the femur. In the early postoperative period, the internal fixation bears the maximum stress, relieves the stress on the femur, and is conducive to fracture healing. However, the maximum equivalent stress in the enhanced PFNA group is smaller, which is more stable than that in the Intertan group, The risk of internal fixation failure is reduced. When using enhanced PFNA fixation, the femur bears less stress and can play a better supporting role. Therefore, enhanced PFNA is a better choice for senile osteoporotic intertrochanteric fracture.