From the Research
Cyclops lesion is a complication that can occur after anterior cruciate ligament (ACL) reconstruction surgery, characterized by the formation of fibrous nodular tissue at the intercondylar notch of the knee, and its primary symptoms include limited knee extension, pain, and impaired function, as reported in a study published in 2021 1. The symptoms of cyclops lesion post ACL knee reconstruction may include:
- Limited knee extension (inability to fully straighten the knee)
- Painful catching or locking sensation when attempting to extend the knee
- Audible clicking or popping
- Swelling around the knee joint, particularly after activity
- Decreased range of motion compared to the pre-surgery state
- Pain felt at the front of the knee, especially during activities that require full extension
- Instability or a feeling that the knee might give way during certain movements These symptoms usually appear 2-6 months after ACL reconstruction when the patient is progressing with rehabilitation, as noted in a study published in 2018 2. The condition occurs because excess fibrous tissue forms during the healing process, creating a mechanical block to full extension, and treatment typically involves arthroscopic removal of the cyclops lesion, followed by physical therapy to regain full extension, with most patients experiencing significant symptom improvement after the nodule is removed, as reported in a study published in 2020 3. It is essential to distinguish between cyclops lesion and cyclops syndrome, as management differs based on symptoms, and arthroscopic debridement is an effective treatment for cyclops syndrome, whereas cyclops lesions are usually managed conservatively, as noted in a study published in 2020 3. The management of choice for symptomatic lesions is surgical excision, and outcomes after excision are very good, and recurrence is rare, as reported in a study published in 2020 3.