Background: The remnant of a ruptured anterior cruciate ligament (ACL) can increase the risk of impingement or a cyclops lesion, which can increase challenges to proper tunnel placement.
Purpose: To evaluate the prevalence of cyclops lesions after ACL reconstruction and to assess the difference in the incidence of cyclops lesions between single-bundle repair and selective bundle repair of the ACL.
Material and methods: This retrospective study included 151 patients who were diagnosed with an ACL tear after knee joint magnetic resonance imaging (MRI) who underwent ACL reconstruction surgery. MRI diagnosis of cyclops lesion formation was made if a soft-tissue mass was seen anteriorly in the intercondylar notch near the tibial insertion of the reconstructed ACL, based on sagittal T2-weighted (T2W) imaging. The size of the cyclops lesions was recorded as the largest diameter on the sagittal T2W imaging.
Results: A cyclops lesion was detected in 74 (38.5%) cases. Cyclops lesions were detected more frequently in cases with single-bundle repair of the ACL, but the results were not statistically significant (P = 0.609). Compared with selective bundle repair, cyclops lesions had a significantly higher prevalence in the posterolateral (PL) bundle repair than in the anteromedial (AM) bundle repair (P = 0.027) based on MR images at 6-12 months after surgery.
Conclusion: The incidence of cyclops lesions did not differ significantly in single-bundle repair and selective bundle repair of ACL. However, selective PL bundle repair of the ACL showed a significantly increased incidence of cyclops lesions compared with selective AM bundle repair.
Keywords: Magnetic resonance imaging; anterior cruciate ligament; arthrofibrosis; meniscus.