Arthroscopic findings of the synovial plicae of the knee.

From June 1991 to March 1993, 400 knees in 363 patients were studied arthroscopically to clarify the arthroscopic anatomy of the plica and determine the classification of the plica. The various patterns of the synovial plicae were classified according to their shape and size from the arthroscopic view. Incidences of the synovial plica at the knees were: suprapatellar plica, 87.0%; mediopatellar plica, 72.0%; infrapatellar plica, 86.0%; and lateral patellar plica, 1.3%. There was no significant correlation in frequencies and distributions of patterns among the four groups of the plica, between men and women, with age, and between right and left. However the significant similarity in patterns of the right and left knees in the same persons was noted.