2025 ISAKOS Biennial Congress ePoster
The Knee Pain Decreases After Total Hip Arthroplasty
Yugo Morita, MD, PhD, Kyoto, --- Select One --- JAPAN
Yaichiro Okuzu, MD, PhD, Kyoto JAPAN
Toshiyuki Kawai, MD, PhD, Kyoto JAPAN
Kohei Nishitani, MD, PhD, Kyoto JAPAN
Shinichiro Nakamura, MD, PhD, Kyoto JAPAN
Yutaka Kuroda, MD, PhD, Kyoto JAPAN
Shinichi Kuriyama, MD, PhD, Kyoto, Kyoto JAPAN
Shuichi Matsuda, MD, PhD, Kyoto JAPAN
Kyoto University Hospital, Kyoto, JAPAN
FDA Status Not Applicable
Summary
Knee pain is common before THA, however, patients, particularly those with a low knee KL grade, may experience improvement in knee pain following THA.
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Abstract
Objective
It has been reported that patients scheduled for total hip arthroplasty (THA) often experience knee pain as well. This study aimed to evaluate the temporal changes in knee pain before and after THA and analyze the factors influencing these changes.
Methods
The study included 185 hips (183 patients) undergoing THA for primary hip osteoarthritis (Primary OA), secondary hip osteoarthritis due to developmental dysplasia of the hip (DDH OA), or osteonecrosis of the femoral head (ONFH). The visual analog scale (VAS) scores for knee pain on the same side were assessed over time preoperatively, and at 3 months, 6 months, and 1 year postoperatively. Factors influencing these scores were also analyzed.
Results
Preoperatively, 52.4% (97 hips) of the patients experienced knee pain on the same side. The proportion of patients with knee pain significantly decreased after THA (3 months post-op: 35.7%, 6 months post-op: 29.2%, 1-year post-op: 23.8%, p<0.0001). The severity of knee pain (knee VAS score) also significantly decreased over time (pre-op: 2.2 → 3 months post-op: 1.1, 6 months post-op: 0.79, 1-year post-op: 0.6, with p-values of 0.0019, <0.0001, and <0.0001 respectively). When analyzed by underlying disease, a significant decrease in knee VAS scores was observed at 1-year post-op for all conditions (Primary OA: 2.1 → 0.7, p=0.013; DDH OA: 2.2 → 0.66, p=0.0004; ONFH: 2.2 → 0.26, p=0.0042). According to multivariate regression analysis, the most influential factor on preoperative knee VAS scores was the preoperative hip VAS score (t=3.3, p=0.0014). The most influential factor on knee VAS scores at 12 months post-op was the knee's Kellgren-Lawrence grade (t=3.8, p=0.0002).
Discussion
Approximately half of the patients experienced knee pain before THA. However, this proportion halved after the surgery. The severity of knee pain also significantly improved postoperatively. Patients with severe hip pain tended to have severe knee pain preoperatively. Patients with a high knee KL grade tended to have persistent knee pain postoperatively.
Conclusion
Patients often experience knee pain before THA. However, especially those with a low knee KL grade may experience improvement in knee pain after THA.