Satoru Tamura1, Shunsaku Nishihara2, Masaki Takao1, Takashi Sakai3, Hidenobu Miki4, Nobuhiko Sugano1. 1. Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita, Japan. 2. Department of Orthopaedic Surgery, Hoshigaoka Medical Center, Hirakata, Japan. 3. Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan. 4. Department of Orthopaedic Surgery, Osaka National Hospital, Hirakata, Japan.
Abstract
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° 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° 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. 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.
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° 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° 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. 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.
Authors: Keisuke Uemura; Penny R Atkins; Masashi Okamoto; Kunihiko Tokunaga; Andrew E Anderson Journal: J Orthop Res Date: 2020-04-30 Impact factor: 3.494
Authors: Mohammadreza Pourahmadi; Mohammad Sahebalam; Jan Dommerholt; Somayeh Delavari; Mohammad Ali Mohseni-Bandpei; Abbasali Keshtkar; César Fernández-de-Las-Peñas; Mohammad Ali Mansournia Journal: BMC Musculoskelet Disord Date: 2022-03-15 Impact factor: 2.362