Fenestrated medial patellar plicae are unusual. In a review of 1,000 consecutive knee arthroscopies, the incidence of this finding was 1.8%. These fenestrations may vary in size and shape from being small, circular, and only 5 mm in diameter to being lengthwise openings 3-4 cm long. There is a high prevalence of associated medial knee symptoms (80%) that are relieved by complete resection. Since the plical fenestration does not appear to abrade the articular cartilage, symptoms are probably the result of medial wall inflammation.