Tamura Satoru, Nishihara Shunsaku, Takao Masaki, Sakai Takashi, Miki Hidenobu, Sugano Nobuhiko
Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita, Japan.
Department of Orthopaedic Surgery, Hoshigaoka Medical Center, Hirakata, Japan.
J Arthroplasty. 2017 Mar;32(3):877-882. doi: 10.1016/j.arth.2016.08.035. Epub 2016 Sep 9.
Functional anteversion and inclination of the cup change as the pelvic sagittal inclination (PSI) changes. The purposes of this study were to investigate the chronological changes of PSI during a 10-year follow-up period after total hip arthroplasty (THA) and to report the characteristics of patients who showed a greater than 10° change in the PSI from the supine to the standing position.
The subjects were 70 patients who were followed up for 10 years after THA. PSI values in the supine and standing positions were measured by 2D-3D matching using computed tomography images and pelvic radiographs. PSI values before THA and 1, 5, and 10 years after THA were compared in both the supine and standing positions.
Supine PSI showed less than 5° of change, whereas standing PSI showed a significant decrease with time over the 10-year period. Although 43% of patients with less than 10° of difference in the PSI between the supine and standing positions before THA increased PSI posteriorly (reclining) more than 10° in standing from the supine position at 10 years, no late dislocation was observed.
Supine PSI showed no significant change, but standing PSI showed a significant increase posteriorly with time over a 10-year period. However, this PSI change did not reach the level that it caused negative consequences such as late dislocation. The pelvic position in the supine position might still be a good functional reference position of the pelvis for aiming to achieve proper cup alignment at 10 years.
髋臼杯的功能前倾角和倾斜度会随着骨盆矢状面倾斜度（PSI）的变化而改变。本研究的目的是调查全髋关节置换术（THA）后10年随访期间PSI的时间变化，并报告从仰卧位到站立位PSI变化大于10°的患者特征。
研究对象为70例THA术后接受10年随访的患者。使用计算机断层扫描图像和骨盆X线片通过二维-三维匹配测量仰卧位和站立位的PSI值。比较THA术前以及THA术后1年、5年和10年仰卧位和站立位的PSI值。
仰卧位PSI变化小于5°，而站立位PSI在10年期间随时间显著降低。虽然术前仰卧位和站立位PSI差异小于10°的患者中，有43%在10年时从仰卧位转为站立位时PSI向后（后倾）增加超过10°，但未观察到晚期脱位。
仰卧位PSI无显著变化，但站立位PSI在10年期间随时间向后显著增加。然而，这种PSI变化未达到导致晚期脱位等不良后果的程度。仰卧位时的骨盆位置可能仍然是旨在在10年时实现髋臼杯正确对线的骨盆良好功能参考位置。
