Unusual cause of internal knee derangement.

A 25-year-old man was referred to our department by the orthopaedic surgeon for intermittent pain at the medial compartment of his knee after a rugby match. There was no history of direct trauma. At clinical examination the internal compartment was tender. There was no instability or blockage at clinical tests. A computed tomo - graphy arthrography (CTA) examination was performed in order to rule out a lesion at the medial knee compartment.