Department of Orthopedics, Luzhou Key Laboratory of Orthopedic Disorders, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China.
Department of Orthopaedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China.
Eur J Med Res. 2024 Jun 18;29(1):336. doi: 10.1186/s40001-024-01892-7.
Femoral head varus triggers poor clinical prognosis in intertrochanteric fracture patients with proximal femoral nail antirotation (PFNA) fixation. Studies present that changes in nail position and screw insertion angles will affect fixation stability, but the biomechanical significance of these factors on the risk of femoral head varus has yet to be identified in PFNA fixed patients.
Clinical data in PFNA fixed intertrochanteric fracture patients have been reviewed, the relative position of intermedullary nail has been judged in the instant postoperative lateral radiography. Regression analyses have been performed to identify the effect of this factor on femoral head varus. Corresponding biomechanical mechanism has been identified by numerical mechanical simulations.
A clinical review revealed that ventral side nail insertion can trigger higher risk of femoral head varus, corresponding numerical mechanical simulations also recorded poor fixation stability in models with ventral side nail insertion, and changes in the trajectory of anti-rotation blade will not obviously affect this tendency.
Ventral side insertion of intramedullary nail can trigger higher risk of femoral head varus in PFNA fixed patients by deteriorating the instant postoperative biomechanical environment, and changes in blade trajectory cannot change this tendency biomechanically. Therefore, this nail position should be adjusted to optimize patients' prognosis.
股骨颈头端内翻会导致股骨近端防旋髓内钉（PFNA）固定的转子间骨折患者临床预后不良。研究表明，钉的位置和螺钉插入角度的变化会影响固定的稳定性，但这些因素对 PFNA 固定患者股骨颈头端内翻风险的生物力学意义尚未确定。
回顾了 PFNA 固定的转子间骨折患者的临床资料，根据即刻术后侧位 X 线片判断髓内钉的相对位置。采用回归分析来确定该因素对股骨颈头端内翻的影响。通过数值力学模拟确定了相应的生物力学机制。
临床回顾显示，前侧钉插入会增加股骨颈头端内翻的风险，相应的数值力学模拟也记录到前侧钉插入的模型固定稳定性较差，而反旋刀片轨迹的变化并不会明显影响这种趋势。
髓内钉的前侧插入会通过恶化即刻术后的生物力学环境，导致 PFNA 固定患者股骨颈头端内翻的风险增加，而刀片轨迹的变化在生物力学上无法改变这种趋势。因此，应调整这种钉的位置以优化患者的预后。
