The effect of total hip arthroplasty on lumbar-pelvic sagittal alignment in patients with primary hip osteoarthritis

Abstract

Objective To investigate the lumbar-pelvic sagittal alignment in primary hip osteoarthritis(HOA) patients without low back pain before and after unilateral total hip arthroplasty(THA), to compare these parameters with normal adults and to analyze its clinical significance. Methods Twenty-nine HOA patients (17 males and 12 females) with an average age of 51.6 years and 45 normal controls (26 males and 19 females) with an average age of 49.2 were recruited for analysis. The radiographs of the lumbar spine were retrospectively reviewed. Harris Hip Score (HHS) was completed by patients. The pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), sacrum pubic incidence (SPI) and sacrum pubic posterior angle (SPPA) were measured on the X-ray films. The sagittal lumbar-pelvic parameters were compared between groups. Results All HOA patients were successfully performed the operation and all patients completed the full study assessments of an average period of 13.6 months (12-18 months). PT in HOA patients before(6.0°±10.6°) and after(6.3°±10.8°) THA were lower than that in normal group(12.4°±8.4°), there were statistical differences (t=4.092, 2.732, all P values 0.05). HHS of HOA patients after THA (86.5±4.1)was larger than that before THA(32.6±6.5), there were statistical differences (t=38.644, P 0.05). Conclusions Avoiding the influence of low back pain and THA does not change the lumbar-pelvic sagittal balance of primary HOA patients and improve their physical quality. Our result may provide the necessary reference to the surgical treatment of patients with HOA and to maintain a good sagittal balance in the future. Key words: Osteoarthritis, hip; Arthroplasty, replacement, hip; Spino-pelvic sagittal alignment