Preoperative posterior pelvic tilt is associated with residual low back pain and inferior patient-reported outcomes after total hip arthroplasty.

PURPOSE: To determine changes in low back pain (LBP) after total hip arthroplasty (THA), identify preoperative factors associated with residual LBP and LBP improvement, and clarify the association between residual LBP and patient-reported outcome measures (PROMs) at one year postoperatively.

METHODS

This retrospective study included 211 patients undergoing primary unilateral THA via a posterolateral approach. LBP visual analog scale (VAS), hip-specific PROMs, and EQ-5D VAS were assessed preoperatively and at one year. Residual LBP was defined as LBP VAS ≥ 20 at  one year, and LBP improvement as a ≥ 20-point decrease in patients with preoperative LBP. Spinopelvic parameters were measured on preoperative standing lateral whole-spine radiographs. Logistic regression analyses were performed to identify factors associated with residual LBP and LBP improvement.

RESULTS

LBP VAS decreased from 31 to 12 (p < 0.001) after THA, and residual LBP was present in 84 patients (40%). Preoperative LBP VAS (OR 1.31, p < 0.001) and pelvic tilt (OR 1.34, p = 0.046) were independently associated with residual LBP. Among 129 patients with preoperative LBP, 71 (55%) achieved LBP improvement. Preoperative LBP VAS (OR 1.33, p = 0.002) and pelvic tilt (OR 0.62, p = 0.006) were independently associated with LBP improvement. Patients with residual LBP had worse one year PROMs.

CONCLUSION

Preoperative posterior pelvic tilt was independently associated with residual LBP and less LBP improvement after THA. Residual LBP was associated with inferior one year PROMs, suggesting a potential role for preoperative sagittal pelvic orientation in persistent LBP and patient-perceived recovery after THA.