Andersen Mikkel R, Petersen Michael M
Department of Orthopedic Surgery, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Department of Orthopedic Surgery, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
J Clin Densitom. 2016 Apr-Jun;19(2):202-7. doi: 10.1016/j.jocd.2015.02.009. Epub 2015 Apr 3.
Loss of bone stock and stress shielding is a significant challenge in limb salvage surgery. This study investigates the adaptive bone remodeling of the femoral bone after implantation of a tumor prosthesis with an uncemented press fit stem. We performed a prospective 1 yr follow-up of 6 patients (mean age: 55 (26-78) yr, female/male=3/3) who underwent bone tumor resection surgery of the proximal femur (n=3) or distal femur (n=3). Reconstruction was done using a Global Modular Replacement System (Stryker® Orthopaedics, Mahwah, NJ) tumor prosthesis, and all patients received a straight-fluted 125-mm uncemented press-fit titanium alloy stem with hydroxyapatite coating of the proximal part of the stem. Measurements of bone mineral density (BMD; g/cm2) were done postoperatively and after 3, 6, and 12 mo in the part of the femur bone containing the Global Modular Replacement System stem using dual-energy X-ray absorptiometry. BMD was measured in 3 regions of interest (ROIs) in the femur bone. Nonparametric analysis of variance (Friedman test) for evaluation of changes in BMD over time. BMD decreased in all 3 ROIs with time. In ROI 1 (p=0.01), BMD decreased by 10% after 3 mo and ended with a total decrease of 14% after 1 yr. In ROI 2 (p=0.006), BMD was decreased by 6% after 3 and 6 mo; after 1 yr of follow-up, BMD was 9% below the postoperative value. In ROI 3 (p=0.009), BMD decreased by 6% after 3 and 6 mo; after 1 yr of follow-up, BMD was 8% below the postoperative value. A bone loss of 8%-9% during the first postoperative year was seen along the femoral stem, but in the bone containing the hydroxyapatite-coated part of the stem, the decrease in BMD was 14%, thus indicating that stress shielding of this part of the bone may play a role for the adaptive bone remodeling.
骨量丢失和应力遮挡是保肢手术中的一项重大挑战。本研究调查了采用非骨水泥压配型柄的肿瘤假体植入后股骨的适应性骨重塑情况。我们对6例患者（平均年龄：55（26 - 78）岁，女性/男性 = 3/3）进行了为期1年的前瞻性随访，这些患者接受了股骨近端（n = 3）或远端（n = 3）的骨肿瘤切除手术。使用全球模块化置换系统（史赛克骨科公司，新泽西州马哈瓦）肿瘤假体进行重建，所有患者均接受了一根直槽125毫米的非骨水泥压配型钛合金柄，柄的近端部分有羟基磷灰石涂层。术后以及在术后3、6和12个月时，使用双能X线吸收法在包含全球模块化置换系统柄的股骨部分测量骨密度（BMD；g/cm²）。在股骨的3个感兴趣区域（ROI）测量BMD。采用非参数方差分析（弗里德曼检验）评估BMD随时间的变化。所有3个ROI的BMD均随时间下降。在ROI 1（p = 0.01），3个月后BMD下降了10%，1年后最终总共下降了14%。在ROI 2（p = 0.006），3个月和6个月后BMD下降了6%；随访1年后，BMD比术后值低9%。在ROI 3（p = 0.009），3个月和6个月后BMD下降了6%；随访1年后，BMD比术后值低8%。术后第一年沿股骨干可见8% - 9%的骨质流失，但在包含柄的羟基磷灰石涂层部分的骨中，BMD下降了14%，因此表明该部分骨的应力遮挡可能对适应性骨重塑起作用。
