Keyak Joyce H, Kaneko Tadashi S, Skinner Harry B, Hoang Bang H
Department of Orthopaedic Surgery, University of California, Irvine, CA 92868-5382, USA.
Clin Orthop Relat Res. 2007 Jun;459:139-45. doi: 10.1097/BLO.0b013e3180514caa.
Metastatic lesions in the proximal femur can reduce hip strength and lead to pathologic fracture. However, current methods for identifying patients at risk of pathologic fracture are inadequate. We hypothesized the percentage of intact proximal femoral strength remaining after formation of a simulated lytic defect within the femoral neck or at the level of the lesser trochanter depends on defect location within the respective region. Computed tomography scan-based finite element models of 12 cadaveric proximal femora were used to evaluate the effect of 20-mm-diameter spherical voids at various locations in the neck and at the level of the lesser trochanter. In both regions, the percentage of intact strength remaining depended on defect location (p < 0.001). In the neck, the strength of specimens with inferomedial defects (median, 50.4% of intact; range, 27.8-71.7%) was less than the strength of specimens with defects located in the center of the neck, superolaterally, or anteriorly (p < 0.05). Near the lesser trochanter, anteromedial defects resulted in the lowest strength (median, 66.6% of intact; range, 49.2-73.8%). Other defects at the level of the lesser trochanter had a markedly smaller effect. These findings may be helpful for evaluating pathologic fracture risk.
股骨近端的转移性病变会降低髋关节强度并导致病理性骨折。然而，目前识别有病理性骨折风险患者的方法并不完善。我们推测，在股骨颈或小转子水平形成模拟溶骨性缺损后，股骨近端剩余完整强度的百分比取决于缺损在各自区域内的位置。使用基于计算机断层扫描的12个尸体近端股骨有限元模型，评估在颈部不同位置以及小转子水平处直径20毫米的球形空洞的影响。在这两个区域，剩余完整强度的百分比均取决于缺损位置（p < 0.001）。在颈部，有下内侧缺损的标本强度（中位数为完整强度的50.4%；范围为27.8 - 71.7%）低于缺损位于颈部中央、上外侧或前方的标本强度（p < 0.05）。在小转子附近，前内侧缺损导致强度最低（中位数为完整强度的66.6%；范围为49.2 - 73.8%）。小转子水平的其他缺损影响明显较小。这些发现可能有助于评估病理性骨折风险。
