Does Pelvic Sagittal Inclination in the Supine and Standing Positions Change Over 10 Years of Follow-Up After Total Hip Arthroplasty?

作者：Tamura Satoru; Nishihara Shunsaku; Takao Masaki; Sakai Takashi; Miki Hidenobu; Sugano Nobuhiko

来源：Journal of Arthroplasty, 2017, 32(3): 877-882.

DOI：10.1016/j.arth.2016.08.035

• total hip arthroplasty
• pelvic sagittal inclination
• supine position
• standing position
• 2D-3D matching

Background: 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 degrees change in the PSI from the supine to the standing position.
Methods: 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.
Results: Supine PSI showed less than 5 degrees of change, whereas standing PSI showed a significant decrease with time over the 10-year period. Although 43% of patients with less than 10 degrees of difference in the PSI between the supine and standing positions before THA increased PSI posteriorly (reclining) more than 10 degrees in standing from the supine position at 10 years, no late dislocation was observed.
Conclusion: 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.

• 出版日期2017-3