Changes in sagittal spino-pelvic alignment after total hip arthroplasty using the Roussouly classification
Pelvic inclination changes after total hip arthroplasty; we determined how sagittal spino-pelvic alignment changed after total hip arthroplasty. We investigated the change in Roussouly classification type and sagittal spino-pelvic alignment after total hip arthroplasty. Sagittal spino-pelvic alignment was investigated in 135 patients who underwent total hip arthroplasty. Prior to surgery, there were 50 cases (37%) of Type 1 and 2, 53 cases (39.3%) of Type 3, and 32 cases (23.7%) of Type 4. Since none of the Type 1 and 2 cases showed postoperative changes, we divided the Type 3 and Type 4 cases into 3 groups. Cases with pelvic retroversion and reduced lumbar lordosis before total hip arthroplasty showed no change. Half of the cases with satisfactory preoperative sagittal spino-pelvic alignment (SSPA) remained Type 3 with lumbar lordosis even after surgery. However, even in satisfactory Type 3 cases, if there was pelvic retroversion after total hip arthroplasty (THA) surgery, they were reclassified as Type 1 or 2 due to reduced lumbar lordosis and changes in SSPA. Cases of Type 4 with preoperative pelvic anteversion were reclassified as Type 3 after surgery due to a major reduction in the sacral slope angle and changes in SSPA. doi：10.11482/KMJ-E42（2）57 (Accepted on October 19, 2016)
