Ipsilateral Knee Pain After Total Hip Arthroplasty: Pathogenesis and Intervention Strategies—A Narrative Review

Background: Total hip arthroplasty (THA) is the optimal surgical procedure for treating end-stage hip diseases. However, ipsilateral knee pain after THA, as a relatively insidious and not yet fully recognized complication, affects patient satisfaction and functional recovery. Its etiology is complex, involving the interaction of mechanisms such as biomechanics, neurobiology, surgical technique, and patient population and individual factors, which requires systematic review to guide clinical intervention. Objective: This review aims to systematically elaborate on the pathogenesis of ipsilateral knee pain after THA and, based on this, propose corresponding intervention strategies. Methods: A narrative literature review was conducted using the PubMed and Scopus databases, an in-depth analysis was conducted from the following aspects: (1) Based on the pathological basis of developmental dysplasia of the hip (DDH), explore the impact of lower limb biomechanical changes after THA on the ipsilateral knee; (2) Analyze the role of neurobiological mechanisms such as referred pain and central sensitization in this complication; (3) Evaluate the influence of surgery-related factors and patient individual and population factors on this complication; (4) Diagnose this complication based on relevant pain score questionnaires, EOS system, predictive simulation, and other imaging and assessment tools; (5) Integrate management approaches from preoperative intervention to postoperative multimodal analgesia. Results: Available evidence suggests that ipsilateral knee pain after THA is a multifactorial condition. A key modifiable surgical risk factor identified is excessive limb lengthening (≥ 17mm), which disrupts native knee biomechanics. The pathogenesis further involves neurobiological mechanisms such as referred pain and central sensitization, surgical technical factors, and patient-related factors. Conclusion: Ipsilateral knee pain after THA arises from a complex interplay of biomechanical, neurobiological, and patient-specific mechanisms. To mitigate this complication, a comprehensive management strategy is recommended, encompassing precise preoperative planning, targeted prehabilitation for high-risk patients, and postoperative multimodal analgesia. Future research should focus on validating specific preventive protocols and management algorithms. Keywords: total Hip arthroplasty, knee pain, biomechanical phenomena, postoperative complications