Medial plicae and degeneration of the medial femoral condyle.

PURPOSE The purpose of this study was to evaluate and analyze the chronological changes of the pathologic medial plica and the chondral lesions on the medial femoral condyle. The relationship between the severity of the pathologic medial plica and that of the chondral lesions on the medial femoral condyle was also investigated. TYPE OF STUDY Retrospective case series study of consecutive patients who underwent arthroscopic surgery. METHODS A retrospective case series study was conducted to review the findings of 1,587 knees of 1,263 patients who had received arthroscopic surgery between 1989 and 2001. The medial plica was classified by its size and the severity of its gross pathologic change. The location and severity of the cartilaginous degeneration on the surface of the medial femoral condyle of these patients were also investigated. The correlation of patient age with the gross pathologic change of their medial plica and the severity of the cartilaginous degeneration on the surface of the medial femoral condyle was analyzed. RESULTS We found that 472 knees (29.7%) of 378 patients (29.9%) had the structure of the medial plica. The incidence was significantly higher (66.9%) in patients with osteoarthritic knees. The severity of the gross pathologic change of the medial plica was positively correlated with patients' age. The size of the plica was found to be smaller in older patients. Two distinct areas of degenerative cartilaginous lesion related to the medial plica were found on the surface of the medial femoral condyle in 97% of the knees with the structure of the medial plica. The severity of the degeneration was positively correlated with patients' age and the severity of the pathologic change of the medial plica. CONCLUSIONS According to our observation, medial plica was more commonly found in patients with osteoarthritic knees. Cartilaginous degeneration on the surface of the medial femoral condyle could be found in most of the knees with a medial plica. The severity of the degeneration was positively correlated with the severity of the medial plica and patients' age. LEVEL OF EVIDENCE Level III.