This study explored the relationship between femoral lateralization and femoral neck-shaft angle after intramedullary nail (IM) fixation for per trochanteric fractures. 70 patients (AO/OTA 31A1-2) were investigated. Anteroposterior (AP) and lateral X-ray views pre- and post-operation were recorded. Patients were classified into three groups according to the position of the medial cortex of the head-neck fragment to that of the femoral shaft: being slightly superomedial (positive medial cortex support, PMCS), being smoothly contacted (neutral position, NP) or being displaced laterally (negative medial cortex support, NMCS). Patient demographics, femoral lateralization, and neck-shaft angle were measured and statistically analyzed pre- and post-operation. Functional recovery was evaluated by Harris score 3- and 6- months post-operation. All cases ultimately demonstrated radiographic fracture union. There was a tendency to have an increased neck-shaft angle (valgus alignment) in the PMCS group and increased femoral lateralization in the NP group (p < 0.05). Among those three groups, the change in femoral lateralization and neck-shaft angle was statistically different (p < 0.05). An inverse relationship between femoral lateralization and femoral neck-shaft angle was observed. Femoral lateralization increased correspondingly when the neck-shaft angle continuously decreased from the PMCS group to the NP group and then to the NMCS group, and patients in the PMCS group had better functional recovery than the other two groups (p < 0.05). Femoral lateralization was commonly produced after IM fixation for per trochanteric fractures. The fracture fixed in PMCS mode possesses the slightest change in femoral lateralization while maintaining valgus alignment of the femoral neck-shaft angle and good functional outcome, which is superior to NP or NMCS mode.

本研究探讨了股骨转子间骨折髓内钉（IM）固定后股骨偏侧度与股骨颈干角之间的关系。对 70 名患者 (AO/OTA 31A1-2) 进行了调查。记录术前和术后的前后位 (AP) 和侧位 X 射线视图。根据头颈碎片内侧皮质与股骨干的位置将患者分为三组：轻微超内侧（正向内侧皮质支撑，PMCS）、平滑接触（中性位置，NP）或横向移位（负内侧皮质支撑，NMCS）。术前和术后对患者人口统计学、股骨偏侧度和颈干角度进行测量和统计分析。术后3个月和6个月通过Harris评分评估功能恢复情况。所有病例最终均显示X线骨折愈合。PMCS 组有颈干角（外翻排列）增加的趋势，NP 组股骨偏侧化有增加的趋势（p < 0.05）。在这三组中，股骨偏侧和颈干角的变化有统计学差异（p < 0.05）。观察到股骨偏侧化与股骨颈干角之间呈反比关系。当颈干角从PMCS组到NP组再到NMCS组持续减小时，股骨偏侧度相应增加，且PMCS组患者的功能恢复优于其他两组（p < 0.05）。股骨偏侧通常是在股骨粗隆骨折的 IM 固定后产生的。PMCS模式固定骨折时，股骨偏侧度变化最小，同时保持股骨颈-干角外翻排列，功能结果良好，优于NP或NMCS模式。