Nishihara Shunsaku, Sugano Nobuhiko, Nishii Takashi, Ohzono Kenji, Yoshikawa Hideki
Department of Orthopaedic Surgery, Osaka University Medical School, Japan.
Clin Orthop Relat Res. 2003 Jun(411):140-51. doi: 10.1097/01.blo.0000069891.31220.fd.
The purpose of the current study was to evaluate whether safe acetabular component position depends on differences in pelvic location between the supine, standing, and sitting positions. The subjects of the current study were 101 patients who had total hip arthroplasty. Anteroposterior radiographs of the pelvis with the patients in the supine, standing, and sitting positions were obtained preoperatively and 1 year after total hip arthroplasty. Computed tomography images of the pelvis were obtained preoperatively. Using image matching between the three-dimensional computed tomography model and anteroposterior radiograph, pelvic flexion angles with the patient in the supine, standing, and sitting positions were calculated. The mean preoperative pelvic flexion angle was 5 degrees +/- 9 degrees (range, -37 degrees -30 degrees ) in the supine position, 3 degrees +/- 12 degrees (range, -46 degrees -33 degrees ) in the standing position, and -29 degrees +/- 12 degrees (range, -62 degrees -10 degrees ) in the sitting position. Because there was much intersubject variability in pelvic flexion angle, it is not appropriate to determine orientation of the acetabular component from anatomic landmarks. In 90% of the cases, the difference in pelvic flexion angle between the supine and standing positions preoperatively was 10 degrees or less. In 90% of the cases, there was 20 degrees or greater extension of the pelvis from the supine position to the sitting position preoperatively, and the safe range of flexion of the hip from anterior prosthetic impingement in the sitting position was 20 degrees or greater than that in the supine position. Preoperative pelvic position in each case was almost completely maintained 1 year after total hip arthroplasty. It is reasonable to regard the pelvic position in the supine position as the functional pelvic position and proper pelvic reference frame in determining optimal orientation of the acetabular component in 90% of cases before and 1 year after total hip arthroplasty, although an adjustment of orientation of the acetabular component was needed for the remaining cases.
本研究的目的是评估髋臼组件的安全位置是否取决于仰卧位、站立位和坐位时骨盆位置的差异。本研究的受试者为101例行全髋关节置换术的患者。术前及全髋关节置换术后1年，获取患者仰卧位、站立位和坐位时骨盆的前后位X线片。术前获取骨盆的计算机断层扫描图像。通过三维计算机断层扫描模型与前后位X线片之间的图像匹配，计算患者仰卧位、站立位和坐位时的骨盆屈曲角度。术前仰卧位时骨盆平均屈曲角度为5°±9°（范围，-37°至30°），站立位时为3°±12°（范围，-46°至33°），坐位时为-29°±12°（范围，-62°至-10°）。由于骨盆屈曲角度在个体间存在很大差异，因此从解剖标志确定髋臼组件的方向是不合适的。在90%的病例中，术前仰卧位和站立位之间的骨盆屈曲角度差异为10°或更小。在90%的病例中，术前从仰卧位到坐位时骨盆有20°或更大的伸展，且坐位时髋关节因前方假体撞击而安全的屈曲范围比仰卧位时大20°或更多。全髋关节置换术后1年，每种情况下的术前骨盆位置几乎完全得以维持。在90%的全髋关节置换术前及术后1年的病例中，将仰卧位时的骨盆位置视为功能性骨盆位置和合适的骨盆参考框架以确定髋臼组件的最佳方向是合理的，尽管其余病例需要调整髋臼组件的方向。
