A term of art for a common—up to 10% of cases–complication of anterior cruciate ligament–ACL–reconstruction, the arthroscopic appearance–bulbous appearance and focal purplish discolouration due to central venous channels–of which has been fancifully likened* to Polyphemus, the Cyclops of Greek mythology
*Honestly, it’s a real “stretch” (see bottom image)
Clinical findings The lesion first appears 2 to 8 months after ACL
repair. The patients report difficulty in fully extending the affected knee, which is accompanied by pain and, with time, an audible and palpable clunk.
Imaging–MRI Anterior or anterolateral soft-tissue mass in the intercondylar notch near the tibial insertion of the repaired ACL. The lesion typically has intermediate to low signal intensity with all pulse sequences due to the lesion’s fibrous content.
Pathology Central granulation tissue surrounded by dense fibrosis.
Management Arthroscopic excision.
Synonym Localised anterior arthrofibrosis
Indian J Radiol Imaging. 2010 August; 20(3): 208–210.