Hagio Keisuke, Sugano Nobuhiko, Nishii Takashi, Miki Hidenobu, Otake Yoshito, Hattori Asaki, Suzuki Naoki, Yonenobu Kazuo, Yoshikawa Hideki, Ochi Takahiro
Department of Orthopaedic Surgery, Osaka University Medical School, 2-2 Yamadaoka, Suita 565-0871, Osaka, Japan.
J Orthop Res. 2004 May;22(3):665-70. doi: 10.1016/j.orthres.2003.10.009.
We have developed a novel system of four-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities. This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system's measurements, open MRI was used to evaluate positions of skin markers against bones in five healthy volunteers in various postures. No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture. The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.
我们开发了一种全髋关节置换术（THA）后四维运动分析的新系统，该系统可以通过评估患者在多种日常活动中的安全运动范围来帮助预防脱位。该系统使用来自CT的骨骼结构数据和来自红外位置传感器的运动捕捉数据。从CT数据重建的三维模型与运动捕捉数据相结合。利用该系统，我们分析了17例接受THA的患者（26髋）从椅子上起身、坐下或坐在椅子上捡东西时的髋关节运动。为了评估该系统测量的准确性，我们使用开放式MRI评估了5名健康志愿者在各种姿势下皮肤标记相对于骨骼的位置。在任何活动中，任何受试者均未发现骨骼和/或植入物之间有撞击。然而，每位患者在最大髋关节屈曲点的平均角度不同。开放式MRI结果表明，本系统髋关节角度的平均误差在每个静态姿势下均在±5度以内。在评估脱位的实际风险时，必须考虑日常活动中骨盆的功能位置。本系统能够进行动态分析，不仅涉及每位患者的组件和骨骼的对齐，还涉及日常运动特征的个体差异。使用该系统进行进一步研究有助于确定预防髋关节脱位的安全运动范围，提高针对患者术后活动的个性化指导的准确性。
