Hypertrophied medial parapatellar plica: a case of a medial plica anatomical variation with insertion to the inter-meniscal ligament in an adolescent athlete treated arthroscopically.

PURPOSE: The present study aims to report the arthroscopic, radiological and clinical appearance of a rare anatomical variation of a hypertrophied medial parapatellar plica with its response to arthroscopic treatment.

CASE PRESENTATION: A 14-year-old female handball athlete presented with a history of left knee injury during her participation in a handball training session and subsequent locked knee at 20º flexion. Tenderness was located at the medial joint line. Plain radiographs of the injured knee were normal. The magnetic resonance imaging revealed a hypertrophic medial parapatellar plica and a horizontal tear of the medial meniscus. A standard knee arthroscopy was performed. An extremely hypertrophied medial plica was identified, covering a great part of the medial femoral condyle extending up to the femoral trochlea. Distally, it was attached into the inter-meniscal ligament. The plica was excised and the medial meniscus tear was repaired. At 1-month post-operatively, the patient was completely asymptomatic and at 3-months she returned to her weekly training routine.

CONCLUSIONS: This study presented a rare anatomical variation of a hypertrophied medial parapatellar plica with atypical course in the medial patellofemoral compartment and insertion into the inter-meniscal ligament. In combination with a medial meniscus tear led to a locked knee. Arthroscopic medial meniscus repair and plica excision resulted in complete resolution of symptoms.