The importance of the mediopatellar synovial plica for chondromalacia patellae.

In 60 autopsy knee joints findings on morphology and topography of medio- and suprapatellar plicae and level of insertion of the medial vastus muscle in relation to localization and degree of severity of chondromalacia were determined. The middle fields were affected most frequently and severely with 70% (chondromalacia class II and III). Thirty specimen with mediopatellar plica could be identified out of which 29 (97%) had class II or III chondromalacia; out of 30 specimen without a plica 18 (60%) showed chondromalacia. Accordingly a significant correlation could be detected between the incidence of chondromalacia and that of a mediopatellar synovial plica. When measuring the level of insertion of the medial vastus muscle class III chondromalacia showed an average level of insertion of 11%, class II of 22%, and class O or I of 30%. These differences are statistically significant. Patellar index, patellar facet angle, and patellar depth angle did not show any direct correlation to chondromalacia. The question arises whether the involution anomaly of the genicular septa and the muscular changes are not a manifestation of the same developmental disorder, thus creating the basis for an imbalance of the dynamic functional structure.