Impact of Severe Hip and Knee Osteoarthritis on Patient-Reported Outcomes and Global Alignment Following Lumbar Spinal Stenosis Surgery

Study Design. Retrospective cohort study. Objective. To evaluate the impact of concomitant severe hip or knee osteoarthritis (OA) on patient-reported outcome measures (PROMs) and global alignment in patients undergoing surgery for lumbar spinal stenosis (LSS). Summary of Background Data. Hip and knee OA frequently coexist with LSS, contributing to diagnostic and therapeutic complexities. Limited evidence exists regarding the impact of severe lower extremity OA on baseline and postoperative outcomes in patients with LSS. Methods. A total of 121 patients with LSS who underwent decompression surgery with or without interbody fusion and completed 1-year follow-up were included. Patients were divided into severe OA and non-severe OA groups based on the Kellgren-Lawrence (KL) classification, with grades 3-4 classified as severe OA. We compared radiographic parameters and PROMs, including the Visual Analog Scale (VAS), Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), and Oswestry Disability Index (ODI), at baseline and 1-year follow-up. Multivariable linear regression was used to assess the effect of severe OA on 1-year postoperative PROMs. Results. Sixty-seven patients (55.4%) had severe hip or knee OA. Severe OA was independently associated with higher VAS scores for low back pain (β=0.234, P =0.030) and leg pain (β=0.272, P =0.012), poorer JOABPEQ scores across multiple domains, and higher ODI scores (β=0.269, P =0.008) at 1-year follow-up. Patients with severe OA exhibited greater sagittal vertical axis and coronal imbalance postoperatively despite comparable spinopelvic mismatch. Additionally, the severe OA group experienced a higher rate of implant-related complications (10.5% vs. 1.9%, P =0.043). Conclusion. Concomitant severe lower extremity OA was associated with worse PROMs, sagittal and coronal alignment following LSS surgery. These findings underscore the importance of recognizing and addressing severe lower extremity OA during preoperative planning for LSS to optimize surgical outcomes.