Background: Cyclops syndrome is characterized by a symptomatic extension deficit attributed to impingement of a cyclops lesion within the intercondylar notch. The syndrome is an important cause of reoperation after anterior cruciate ligament reconstruction (ACLR). It has been suggested that remnant-preserving ACLR techniques may predispose to cyclops syndrome, but there is very limited evidence to support this. In general terms, risk factors for cyclops syndrome are not well-understood. Purpose: To determine the frequency of and risk factors for reoperation for cyclops syndrome in a large series of patients after ACLR. Study Design: Case-control study; Level of evidence, 3. Methods: A retrospective analysis of prospectively collected data was performed, including all patients who underwent primary ACLR between January 2011 to December 2017. Patients undergoing major concomitant procedures were excluded. Demographic data, intraoperative findings (including the size of preserved remnants), and postoperative outcomes were recorded. Those patients who underwent reoperation for cyclops syndrome were identified, and potential risk factors were evaluated in multivariate analysis. Results: A total of 3633 patients were included in the study, among whom 65 (1.8%) underwent reoperation for cyclops syndrome. Multivariate analysis demonstrated that preservation of large remnants did not predispose to cyclops lesions (odds ratio [OR], 1.11; 95% CI, 0.63-1.93). The most important risk factor was extension deficit in the early postoperative period. If present at 3 weeks postoperatively, it was associated with a >2-fold increased risk of cyclops syndrome (OR, 2.302; 95% CI, 1.268-4.239; P < .01), which was increased to 8-fold if present 6 weeks after ACLR (OR, 7.959; 95% CI, 4.442-14.405; P < .0001). None of the other potential risk factors evaluated were found to be significantly associated with an increased frequency of cyclops syndrome. Conclusion: Failure to regain full extension in the early postoperative period was the only significant risk factor for cyclops syndrome after ACLR in a large cohort of patients. Other previously hypothesized risk factors, such as preservation of a large anterior cruciate ligament remnant, did not predispose to the development of this debilitating postoperative complication.

Lateral extraarticular procedures (LEAPs) in the anterior cruciate ligament (ACL)-injured knee were widely abandoned in the 1990s but have seen a recent resurgence. The aim of this review was to demonstrate that anterolateral ligament reconstruction (ALLR) is associated with evidence of significant advantages and no evidence of historical concerns. A narrative review of the literature was performed. Combined ACL + ALLR is associated with improved outcomes when compared against isolated ACL reconstruction, including a significantly lower risk of ACL graft rupture (hazard ratio [HR]: 0.327, 95% CI: 0.130–0.758), a significantly lower risk of reoperation for secondary meniscectomy following medial meniscal repair at the time of ACL reconstruction (HR: 0.443, 95% CI: 0.218–0.866), significantly increased likelihood of return to the preinjury level of sport following primary (odds ratio [OR]: 1.938, 95% CI: 1.174–3.224) and revision ACL reconstruction (57.1 vs. 25.6%, respectively; p = 0.008), and in chronic ACL injuries, less residual pivot shift (9.1 vs. 35.3%, p = 0.011), and better IKDC (92.7 ± 5.9 vs. 87.1 ± 9.0, p = 0.0013) and Lysholm (95.4 ± 5.3 vs. 90.0 ± 7.1, p < 0.0001) scores, and no evidence of historical concerns. Combined ACLR + ALLR is associated with excellent clinical outcomes with no evidence of the adverse events that led to the historical widespread abandonment of other types of LEAP. Specifically, comparative series have demonstrated significant advantages of ALLR when compared against isolated ACLR with respect to reduced rates of ACL graft rupture, secondary meniscectomy, persistent instability, and significantly improved functional outcomes and improved return to sport metrics.

Among the different structures of the posterolateral corner, only the arcuate ligament has a significant role in restricting excessive primary and coupled external rotation. The popliteus muscle-tendon unit is not a primary static stabilizer to tibial external rotation at 90° of knee flexion. The posterior cruciate ligament is the primary restraint to excessive recurvatum and posterior tibial translation. The posterior cruciate ligament and the arcuate ligament have predominant role for the posterolateral stability of the knee. The functional restoration of these ligaments is an important part of the surgical treatment of posterolateral ligamentous injuries.