A consecutive series of 28 patients (31 knees) with a symptomatic mediopatellar plica without concomitant lesions excised arthroscopically under local anaesthesia in the outpatient department is described. The results were classified as excellent or good in 26/31 cases after a median follow-up period of 15 months. It is concluded that excising a fibrosed mediopatellar plica large enough to cover the medial femoral condyle during flexion is followed by good results; local anaesthesia is sufficient and economical, and arthroscopic excision under local anaesthesia carries a low morbidity.