Cohort-Based Evaluation of the Risk of Low Back Pain After Total Hip Arthroplasty: A Long-Term Study

Low back pain (LBP) is a potential complication after total hip arthroplasty (THA). However, some studies suggest that THA not only alleviates joint pain but also resolves LBP in up to 88.2% of patients. Most of these observations are limited to short-term follow-ups. This study investigates the long-term relationship between THA and LBP, challenging the notion that THA resolves LBP. A retrospective review was conducted on 236 patients who underwent THA (2010-2020). Multiple statistical models were applied, including unadjusted unmatched, adjusted unmatched, adjusted matched, and target trial emulation with 7887 subjects, to evaluate LBP incidence. Of the 236 patients, 119 developed postoperative LBP. The unadjusted unmatched analysis showed a relative risk (RR) of 2.23 (95%CI: 1.5-3.2). Adjusting for age, sex, body mass index (BMI), and recruitment period reduced the RR to 1.64 (95%CI: 1.0-2.6). The adjusted matched analysis showed an RR of 1.09 (95%CI: 0.4-3.0), while the target trial emulation simulated an RR of 1.03 (95%CI: 0.7-1.8), indicating no significant differences. Despite an apparent initial association, adjusted analyses do not support a significant long-term relationship between THA and LBP. No reduction in postoperative LBP incidence was observed, suggesting THA is safe regarding LBP risk but lacks a curative effect. Rigorous confounding adjustment is essential in retrospective studies.