Medial Plica Syndrome

SYMPTOMS

There is gradual onset of diffuse or localised exercise-induced pain around the anterior part of the knee. Prolonged sitting and squatting often trigger the symptoms (positive movie sign). Walking down stairs is worse than up. Clicking or pseudo-locking during deep squats are common.

AETIOLOGY

The medial plica is a vestigial tissue that many people have but with no symptoms. It connects the anterior fat pad with the medial knee joint capsule. Pain from an inflamed or fibrotic plica may either occur from direct contusions or sometimes as a result of sudden changes in training habits, such as an increase in intensity or amount of impact.

CLINICAL FINDINGS

There is effusion and tenderness on palpation in the medial anterior joint line. The plica test is often positive.

INVESTIGATIONS

X-ray can exclude fractures, OCD, osteochondral injuries and bone tumours. MRI can exclude soft tissue tumours and other localised soft tissue lesions but often miss the plica since it is commonly seen in unsymptomatic knees. MRI thus often underestimates chondromalacia and other superficial chondral injuries as well as many meniscal tears and medial plica syndrome. Ultrasound can be useful for differentiating functional tendon and ligament disorders such as jumper’s knee or tendinosis around the knee. This condition is usually diagnosed and treated by arthroscopy.

TREATMENT

Arthroscopic excision of the painful plica shows excellent outcomes.

REFERRALS

These patients are very much helped by being evaluated clinically by their physician, surgeon and physiotherapist in close collaboration since there are many differential diagnoses (see anterior knee pain).

EXERCISE PRESCRIPTION

Cycling and swimming are good alternatives to keep up general fitness. Running and jumping is usually allowed
within a few weeks of surgery.

EVALUATION OF TREATMENT OUTCOMES

Normal clinical symptoms and signs.

DIFFERENTIAL DIAGNOSES

Meniscus tear, chondral injuries, OCD, chondromalacia patellar, patella instability or mal-tracking, quadriceps
insufficiency, Sinding-Larsen’s syndrome, synovitis, PVNS, patellar tendon disorders, referred pain, secondary
symptoms from ankle or back insufficiency, core instability and more.

PROGNOSIS

Excellent but frequently these patients return with this painful condition in the other knee.