Impact of Wiberg Patellar Morphology on Patient-Reported Outcomes Following Unicompartmental Knee Arthroplasty: A 3~5 Year Retrospective Cohort Analysis

Background Postoperative outcomes and patient satisfaction following unicompartmental knee arthroplasty (UKA) are influenced by multiple factors, with patellofemoral joint pain being a predominant concern. Nevertheless, whether the Wiberg patellar classification system affects functional outcomes and satisfaction remains unclear. This study aimed to evaluate the impact of different patellar types on UKA outcomes. Methods A retrospective analysis was conducted on 327 clinical cases from January 1, 2020, to December 31, 2023. The cohort comprised 59 cases of Type I patella, 200 cases of Type II patella, and 68 cases of Type III patella, with follow-up durations ranging from 18 to 63 months. This study evaluated the effects of the three patient groups on the following parameters: age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, Hospital for Special Surgery (HSS) knee score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Forgotten Joint Score-12 (FJS-12), Feller score, and patient satisfaction. Results The three patient groups exhibited statistically significant differences in satisfaction, FJS-12, and Feller scores. Postoperative knee function improved significantly in all groups compared to preoperative levels. Further analysis of the Feller score components revealed notable distinctions between Type II and Type III patellar morphologies, particularly in satisfaction, FJS-12 scores, and Feller subscores (including anterior knee pain [AKP], stair-climbing ability, and sit-up capacity). However, no significant intergroup differences were observed in age, BMI, ASA classification, HSS score, WOMAC index, or quadriceps strength (Feller assessment). Conclusion UKA effectively improves knee osteoarthritis symptoms. While patellar classification did not influence overall functional outcomes, Type III patellae had inferior patient-reported outcomes. Preoperative planning should address patellar morphology in Type III cases. Trial registration Our clinical trial was approved by the Ethics Committee of the People's Hospital of Ningxia Hui Autonomous Region, and the ethical code was No.2025WJW004