An unperforated suprapatellar plica presenting as a mass: A case report.

Unperforated suprapatellar plica leading to compartmentalization of the knee joint has been seldom reported and occasionally overlooked. We report a rare case of unperforated suprapatellar plica presenting as a suprapatellar mass after trauma in a 20-year-old male. Magnetic resonance imaging (MRI) revealed haemarthrosis without abnormalities. Despite one month of conservative treatment including joint aspiration, a palpable mass was discovered at knee flexion. MRI revealed haemorrhagic fluid in the localized suprapatellar recess with an unperforated suprapatellar plica. The patient underwent successful arthroscopic plica excision and had no recurrence or complaint at the 6-month follow-up visit.