ARTHROSCOPIC ANATOMY OF THE INFRAPATELLAR PLICA

The infrapatellar plicae, ligamentum mucosum, were examined by arthros copy in 200 knees. They were classified into five patterns according t o the characteristics of the morphologic findings: separate type in 12 1 cases (60.5%), split type in 27 cases (13.5%), vertical septum type in 21 cases (10.5%), and fenestra type in 2 cases (1.0%). The remainin g 29 cases (14.5%) did not have any infrapatellar plica, which were de fined as absent type. Hence, the incidence of the infrapatellar plica was 85.5% of the 200 knees examined, There was no significant differen ce between right and left knees in the distribution pattern of the pli ca types. The incidence of the infrapateliar plicae decreased as the a ge increased. Both knees showed the same pattern in the 9 of 16 cases in which a bilateral comparison of the infrapatellar plicae was made.