目的 针对髋关节置换术后患者步态运动水平变化,研究了假体周围骨密度变化趋势,揭示了置换初期、长期运动变化对骨重建的影响规律,为术后康复提供理论依据。方法 基于自适应骨重建理论,建立了股骨-假体有限元模型,以术后初期、长期步态水平作为重建参数计算假体周围骨密度分布,采用Gruen分区方法量化骨密度变化。结果 术后初期恒定步态组与变化步态组骨密度存在明显差异,最大差异发生在低步态组中,造成大转子区域骨密度减小41%；步态运动提高促进假体近端、中端骨密度变化,显著影响发生在大转子区域,造成骨密度增加47%；术后长期阶段,步态运动提高促进假体中端,末端区域骨密度恢复,骨密度增加2%~9%。结论 研究结果为髋关节置换后患者康复过程提供指导。
Objective In order to clarify the changes in gait level of patient after hip replacement, the variation trend of bone density around the implant was studied. It reveals the influence of gait level in postoperative initial and long-term stages on bone density around the implant, which provides the theoretical basis for postoperative rehabilitation. Methods Based on adaptive bone remodeling theory, a femoral-prosthesis finite element model was developed. The distribution of bone density was calculated using the initial and long-term gait level after surgery as the remodeling parameter. Gruen method was applied to quantify the change of bone density. Results In the postoperative initial stage, obvious variation exists in constant gait and change gait groups. The maximum difference occurs in the low gait group, resulting in the reduce of bone density of 41% in the greater trochanter region, the improvement of gait level promotes the enhancement of bone density in proximal and middle end of prosthesis, resulting in the increase of bone density (47%). Long-term gait recovery is responsible for the enhancement of bone density in the middle and end of prosthesis (2%~9%). Conclusions The research findings provide guidance for the rehabilitation process of patients after hip replacement.