Department of Physical Medicine and Rehabilitation, Jyväskylä Central Hospital, and Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
BMC Musculoskelet Disord. 2011 May 19;12:100. doi: 10.1186/1471-2474-12-100.
Hip resurfacing arthroplasty (HRA) is considered a bone-preserving procedure and may eliminate proximal femoral stress shielding and osteolysis. However, in addition to implant-related stress-shielding factors, various patient-related factors may also have an effect on bone mineral density (BMD) of the proximal femur in patients with HRA. Thus, we studied the effects of stem-neck angle, demographic variables, and physical functioning on the BMD of the proximal femur in a one-year follow-up.
Thirty three patients (9 females and 24 males) with a mean (SD) age of 55 (9) years were included in the study. BMD was measured two days and 3, 6, and 12 months postoperatively and 10 regions of interest (ROI) were used. Stem-neck angle was analyzed from anteroposterior radiographs.
Three months postoperatively, BMD decreased in six out of 10 regions of interest (ROI) on the side operated on and in one ROI on the control side (p<0.05) compared to the second postoperative day. At 12 months, BMD had increased in 7 ROIs on the operated side and one ROI on the control side (all p<0.001). Correlation was found between the stem-neck angle and BMD in ROIs 2, 3, 7, and 9 (r=0.36-0.61). In multiple regression analysis, stem-neck angle, age, sex, body mass index, and walking distance did not explain the BMD changes.
After an early drop, the BMD of the upper femur was restored and even exceeded the preoperative level at one year follow-up. From a clinical standpoint, the changes in BMD in these HRA patients could not be explained by stem-neck angle or patient related factors.
髋关节表面置换术（HRA）被认为是一种保骨手术，可消除股骨近端的应力遮挡和骨溶解。然而，除了与植入物相关的应力遮挡因素外，各种与患者相关的因素也可能对 HRA 患者股骨近端的骨密度（BMD）产生影响。因此，我们研究了柄颈角、人口统计学变量和身体功能对 HRA 患者股骨近端 BMD 的影响。
本研究纳入了 33 名患者（9 名女性，24 名男性），平均年龄为 55（9）岁。术后 2 天、3、6 和 12 个月分别测量了 BMD，并使用了 10 个感兴趣区域（ROI）。从前后位 X 线片分析了柄颈角。
术后 3 个月，与术后第 2 天相比，手术侧的 10 个 ROI 中有 6 个（ROI）和对侧的 1 个 ROI 的 BMD 下降（p<0.05）。术后 12 个月，手术侧的 7 个 ROI 和对侧的 1 个 ROI 的 BMD 增加（均 p<0.001）。在 ROI 2、3、7 和 9 中，柄颈角与 BMD 之间存在相关性（r=0.36-0.61）。多元回归分析表明，柄颈角、年龄、性别、体重指数和步行距离不能解释 BMD 的变化。
在早期下降后，股骨上段的 BMD 在 1 年随访时得到恢复，甚至超过了术前水平。从临床角度来看，这些 HRA 患者的 BMD 变化不能用柄颈角或患者相关因素来解释。
