Flexion contracture due to cyclops lesion after bicruciate-retaining total knee arthroplasty

Flexion contracture may develop after total knee arthroplasty (TKA) and is usually associated with soft tissue contracture in the posterior compartment or hamstrings. A cyclops lesion is a soft tissue mass which can form in the anterior compartment usually after anterior cruciate ligament reconstruction and has been observed after bicruciate-retaining TKA. We have treated a patient who developed progressive loss of full extension from 0° to 20° after bicruciate-retaining TKA. A large fibrous tissue mass (cyclops lesion) was identified in the anterior compartment during arthrotomy 1 year after TKA. Excision of the mass resulted in complete resolution of the flexion contracture.