Cyclops Lesions of the Knee: A Narrative Review of the Literature

Abstract

Cyclops lesion is a known complication of anterior cruciate ligament reconstruction (ACLR). Although the incidence of cyclops lesion appears to be decreasing, it remains an important cause of restriction of extension after ACLR. We reviewed the available literature regarding the cyclops lesion and syndrome and cyclops-like lesions to analyze available evidence on cyclops lesions and variants of cyclops lesions. A keyword search in PubMed, Scopus, Web of Science, and EMBASE, Ovid Medline, and Ovid journals provided 47 relevant articles in the English literature, which were used to create this review. We classified cyclops lesions based on clinical presentation, pathology, and location. Risk factors, management options, tips to reduce the condition, and controversies related to the condition have been discussed. Female sex, greater graft volume, bony avulsion injuries, excessively anterior tibial tunnel, double-bundle ACLR, and bicruciate-retaining arthroplasty appear to predispose patients to cyclops lesions. Cyclops syndrome is a cyclops lesion that causes a loss of terminal extension. Arthroscopic debridement is an effective treatment for cyclops syndrome, whereas cyclops lesions are usually managed conservatively. It is important to distinguish between cyclops lesion and cyclops syndrome, as management differs based on symptoms. Cyclops lesion is diagnosed using magnetic resonance imaging. The management of choice for symptomatic lesions is surgical excision. Outcomes after excision are very good, and recurrence is rare.

Occurrence Rate of Cyclops Lesion After Anatomic Double-Bundle ACL Reconstruction: Comparison Between Remnant Tissue Preservation and Resection Methods

“…In addition, there was a significant difference in the location of the cyclops lesion between the groups. The number of tibialside cyclops lesions (type 3 according to Kambhampati et al 19 ) was significantly higher in group B than in group A (P ¼ .0354). In group B, all lesions were located at the tibial side.…”

“…Dash indicates not available. c Classified according to location relative to the graft: femoral side (type 1), midsubstance (type 2), or tibial side (type 3). 19 Type 4 (accordion-type lesions) were located anterior to the anterior cruciate ligament graft. …”

“…On second-look arthroscopy, the occurrence rate of the cyclops lesion was significantly less in group A than in c Classified according to location relative to the graft: femoral side (type 1), midsubstance (type 2), or tibial side (type 3). 19 Type 4 (accordion-type lesions) were located anterior to the anterior cruciate ligament graft. group B (13.3% vs 29.1%; P ¼ .0139) (Table 2).…”

Case Report: Arthrofibrosis of the Knee After Anterior Cruciate Ligament Reconstruction: Anterior Interval Scarring and Cyclops Lesion

“…2). It is estimated that 1% to 10% of ACLRs may form cyclops lesions; however, the majority may be asymptomatic 5 . Symptomatic cyclops lesions will often present with anterior knee pain specifically at terminal knee extension.…”

A Multi-Systems Approach to Human Movement after ACL Reconstruction: The Musculoskeletal System

“…Although less frequently implemented, persistent extension loss may also be treated with splinting or additional surgical procedures. 10,102 Knee flexion ROM should also be progressed during the early post-operative period. General guidelines include targets of 90-100 degrees by one week post-operatively and increases of ~10 degrees per week after that.…”