The synovial plicae in the knee joint.

OBJECTIVE To investigate and evaluate the prevalence of 4 kinds of synovial plicae named according to patella, which are inferior, medial, lateral and superior. METHODS We evaluated plicae in 318 knee arthroscopies through video records, obtained from January 1994 to December 2002 in the Arthroscopy Unit, Department of Orthopedic Surgery, Faculty of Medicine, Trakya University, Edirne, Turkey. In addition, we also investigated plicae in 7 bilateral knee cadavers. RESULTS In the arthroscopic evaluation, the prevalence of infrapatellar synovial plica was 194 (61%), mediopatellar plica was 302 (95%), lateral patellar plica was 66 (20.7%) and suprapatellar plica was 184 (57.8%). We found that there were 8 (57%) infrapatellar synovial plicae, 13 (92%) mediopatellar plicae, 7 (50%) lateral patellar plicae and 6 (42%) suprapatellar plicae in 14 cadaveric knees. CONCLUSION We observed a high prevalence of lateral plicae and mediopatellar plicae on the cadavers and the people with arthroscopic diagnosis, and believe our results can contribute to knee anatomy and surgery.