Sonographic and Magnetic Resonance Imaging Examination of a Cyclops Lesion After Anterior Cruciate Ligament Reconstruction: A Case Report.

OBJECTIVE: This case report describes magnetic resonance imaging (MRI) and diagnostic ultrasound (US) findings for a patient with arthrofibrosis related to a complication of anterior cruciate ligament (ACL) reconstruction.

CLINICAL FEATURES: A 25-year old man presented with right knee pain and loss of extension 5 years after ACL reconstruction. MRI and sonographic examination revealed a soft tissue mass anterolateral to the ACL graft consistent with a cyclops lesion. The lesion was surgically resected and physical therapy was followed postoperatively.

INTERVENTION AND OUTCOME: The patient reported that full range of motion was restored 6 weeks after resection and a course of physical therapy. MRI is the modality of choice for diagnosis, but US may be useful in the diagnosis of this condition.

CONCLUSION: Cyclops lesions may complicate ACL reconstruction or acute ACL injuries. The patient may present with pain and loss of extension, which can be debilitating. MRI and US can be used to diagnose this condition in a timely manner, ensuring optimal clinical outcomes.