The incidence of infrapatellar plicae in the elderly Welsh population.

There are several studies reporting the incidence of suprapatellar, medial, and lateral plicae, but there is very limited information regarding the incidence of the infrapatellar plica. The purpose of our study was to record the incidence of infrapatellar plicae in the elderly Welsh population suffering from knee osteoarthritis. A prospective study was performed and 90 knees with severe osteoarthritis of the knee joint (Kellgren-Lawrence type III and IV) were investigated during total knee arthroplasty surgery. Documentation was performed at every total knee replacement surgery for the length of the study. Knee replacement was performed by one senior surgeon. Infrapatellar plica was investigated by a medial parapatellar approach and was classified into five types according to Kim's classification. The overall incidence of infrapatellar plicae was 37.7%. The most common type of plicae was the separate type (23.3%). There was no significant difference found between male and female patients. The fenestra type was the least common (2.22%). The incidence of infrapatellar plicae in the elderly Welsh population suffering from knee osteoarthritis was significantly lower when compared to a study that recorded the incidence of infrapatellar plica in young patients. Possibly, the degenerative changes of the knee joint can cause the resorption of the infrapatellar plica, thus decreasing its incidence in the elderly population.