Miki Hidenobu, Kyo Takayuki, Kuroda Yasuo, Nakahara Ichiro, Sugano Nobuhiko
Department of Orthopedic Surgery, Osaka National Hospital, Osaka, Japan.
Department of Orthopedic Surgery, Medical School of Osaka University, Osaka, Japan.
Clin Biomech (Bristol). 2014 Jun;29(6):607-13. doi: 10.1016/j.clinbiomech.2014.05.002. Epub 2014 May 21.
Proper implant orientation is essential for avoiding edge-loading and prosthesis impingement in total hip arthroplasty. Although cup orientation is affected by a change in pelvic tilt after surgery, it has been unclear whether surgeons can prevent impingement and edge-loading by proper positioning by taking into account any change in pelvic alignment associated with alteration of hip range of motion.
We simulated implant orientation without edge-loading and prosthesis impingement, even with a change in pelvic tilt and associated change in hip range of motion after surgery, by collision detection using implant models created with computer-aided design.
If posterior pelvic tilting with a corresponding hyperextension change in hip range of motion after surgery remains within 10°, as occurs in 90% of cases, surgeons can avoid edge-loading and impingement by correctly orienting the implant, even when using a conventional prosthesis. However, if a 20° change occurs after surgery, it may be difficult to avoid those risks.
Although edge-loading and impingement can be prevented by performing appropriate surgery in most cases, even when taking into account postoperative changes in pelvic tilt, it may also be important to pay attention to spinal conditions to ensure that pelvic tilting is not extreme because of increasing kyphosis.
在全髋关节置换术中，合适的植入物方向对于避免边缘负荷和假体撞击至关重要。虽然髋臼方向会受到术后骨盆倾斜变化的影响，但尚不清楚外科医生能否通过考虑与髋关节活动范围改变相关的骨盆排列变化来通过适当定位预防撞击和边缘负荷。
我们通过使用计算机辅助设计创建的植入物模型进行碰撞检测，模拟了即使在术后骨盆倾斜和髋关节活动范围发生相关变化的情况下，也不会出现边缘负荷和假体撞击的植入物方向。
如果术后伴有相应髋关节活动范围过伸变化的骨盆后倾保持在10°以内（90%的病例会出现这种情况），即使使用传统假体，外科医生也可以通过正确定向植入物来避免边缘负荷和撞击。然而，如果术后发生20°的变化，可能难以避免这些风险。
虽然在大多数情况下，即使考虑到术后骨盆倾斜的变化，通过进行适当的手术可以预防边缘负荷和撞击，但关注脊柱状况以确保骨盆倾斜不会因脊柱后凸增加而变得极端也可能很重要。
