Müller Marc A, Hengg Clemens, Krettek Christian, van der Velde Detlef, Eberdorfer Siegfried, Stange Richard, Hofmann Gunther O, Platz Andreas, Suhm Norbert
Department of Orthopedic Surgery and Traumatology, University Hospital Basel, Switzerland.
Department of Trauma Surgery and Sports Medicine, University Hospital Innsbruck, Austria.
J Orthop Res. 2015 Nov;33(11):1680-6. doi: 10.1002/jor.22934. Epub 2015 May 18.
This study assessed whether mechanically measured trabecular bone strength is an independent predictor of dynamic hip screw (DHS) stability, i.e., DHS migration (DHSM) after the fixation of proximal femoral fractures. One-hundred and seven patients older than 50 years with proximal femoral fractures were included. During fracture fixation, a mechanical probe (DensiProbe™ Hip) was inserted at the site where the DHS tip would ultimately be positioned. Peak torque to breakaway the trabecular bone was measured. Fracture reduction, primary implant position and postoperative DHSM were assessed by radiographs taken postoperatively, at 6 and 12 weeks after surgery. Univariate regression analysis revealed no association between peak torque and DHSM (R(2) = 0.025, p = 0.135). DHSM correlated with the primary DHS position, i.e., the distance between the DHS and (i) the central femoral neck axis (CNFAD, R(2) = 0.230; p < 0.0001) and (ii) the apex of the femoral head (R(2) = 0.110; p = 0.001). DHSM did not correlate with areal BMD of the contralateral proximal femur. Multivariable regression modeling revealed the CFNAD as predictive factor for screw migration. The primary implant position measured by the CFNAD, rather than DensiProbe™ Hip measured bone strength, is an independent predictor of DHSM.
本研究评估了通过机械测量得到的小梁骨强度是否是动力髋螺钉（DHS）稳定性的独立预测指标，即股骨近端骨折固定后DHS的移位情况（DHSM）。纳入了107例年龄大于50岁的股骨近端骨折患者。在骨折固定过程中，将一个机械探头（DensiProbe™ Hip）插入DHS尖端最终要放置的部位。测量小梁骨断裂的峰值扭矩。通过术后、术后6周和12周拍摄的X线片评估骨折复位情况、初次植入物位置和术后DHSM。单因素回归分析显示峰值扭矩与DHSM之间无关联（R² = 0.025，p = 0.135）。DHSM与初次DHS位置相关，即DHS与（i）股骨颈中心轴（CNFAD，R² = 0.230；p < 0.0001）和（ii）股骨头顶点之间的距离（R² = 0.110；p = 0.001）。DHSM与对侧股骨近端的骨密度面积不相关。多变量回归模型显示CFNAD是螺钉移位的预测因素。通过CFNAD测量的初次植入物位置，而非DensiProbe™ Hip测量的骨强度，是DHSM 的独立预测指标。
