Abstract
OBJECTIVE: The objective of this study is to identify and analyze the risk factors associated with anterior knee pain (AKP) following unicompartmental knee arthroplasty (UKA) and to investigate the underlying mechanisms that contribute to this postoperative complication. METHODS: This case-control study encompassed 30 knees from 24 patients who underwent medial fixed-platform UKA for knee osteoarthritis between 2018 and 2022. Participants were categorized into two groups based on the presence or absence of postoperative AKP. Clinical and imaging data were collected. Logistic regression analysis was utilized to determine independent risk factors for AKP. RESULTS: Among the 30 knees assessed, 7 (23.3 %) exhibited AKP postoperatively, while 23 (76.7 %) did not report such pain. An analysis of imaging parameters revealed significant differences between the two groups regarding postoperative patellar tilt angle, trochlear groove angle, progression of medial patellofemoral arthritis, and postoperative medial tilt of the patella. Logistic regression analysis identified the progression of medial patellofemoral arthritis as an independent risk factor for the occurrence of AKP. Additionally, an increased patellar tilt angle was identified as a protective factor, whereas postoperative medial tilt of the patella was recognized as a risk factor. CONCLUSION: The progression of medial patellofemoral arthritis is identified as an independent risk factor for AKP following fixed-platform UKA. The development of this condition may be influenced by postoperative patellar tilt and trochlear groove angle. These findings underscore the necessity for optimal implant positioning and effective soft tissue management during UKA to mitigate postoperative complications.