Identifying Predictors of Unsatisfactory Outcomes After Unicompartmental Knee Arthroplasty: A Retrospective Cohort Analysis of 978 Patients

Background Medial compartment knee osteoarthritis is common. Unicompartmental knee arthroplasty (UKA) offers a bone-preserving alternative to total knee replacement. Despite its advantages, patient dissatisfaction remains a concern, impacting perceived success beyond implant survival rates. Current evidence lacks a focused analysis of the specific factors driving patient dissatisfaction after UKA, particularly regarding residual symptoms and functional limitations. This study aimed to identify the key independent risk factors for dissatisfaction following UKA. Methods A retrospective analysis was conducted on the clinical data of patients who underwent UKA in the Department of Joint Surgery, Ningxia Hui Autonomous Region People's Hospital, between January 1, 2017, and December 31, 2023. Postoperative outcome data were collected via telephone and outpatient follow-up. Results Univariate analysis revealed significant differences (P < 0.05) between the satisfied and dissatisfied groups regarding surgeon-related factors, prosthesis type, patellar Wiberg classification, age, kneeling ability, stair-related pain, walking pain, knee instability, HSS score, WOMAC score, and FJS score. No significant differences were found in operative side, gender, BMI, ASA grade, symptom duration, or posterior tibial slope. Multivariate logistic regression analysis identified kneeling difficulty, stair-related pain, walking pain, and knee instability as independent risk factors for dissatisfaction. Conclusion Multivariate analysis indicates that postoperative kneeling difficulty, stair-related pain, walking pain, and knee instability are independent risk factors for patient dissatisfaction. Additionally, factors related to the surgeon (as evidenced by inter-surgeon variation in outcomes), prosthesis type, and preoperative patellar morphology were also associated with satisfaction levels. Trial registration It is a retrospective registered, no registration was performed.