Practice Patterns, Controversies, and Proposed Management Algorithm for Cyclops Syndrome After Anterior Cruciate Ligament Reconstruction: An International Survey.

Abstract

Cyclops syndrome remains a clinically relevant cause of extension deficit after anterior cruciate ligament reconstruction (ACLR), yet its prevention, diagnosis, and management are not standardized. The purpose of this study was to characterize practice patterns, identify areas of consensus and controversy, and derive a clinically applicable management framework based on an international survey of knee surgeons. A 69-item online survey was distributed to orthopaedic surgeons specialized in knee surgery through multiple international societies. The questionnaire explored five domains: surgeon characteristics, surgical techniques, preventive strategies, diagnostic approaches, and management of cyclops syndrome. Descriptive statistics were used to summarize responses. A total of 250 surgeons from 25 countries completed the survey. Most respondents estimated the incidence of cyclops syndrome between 1% and 5%, with symptomatic presentation typically occurring within 3-6 months after ACLR. Loss of extension greater than 5° was consistently identified as the key clinical finding. Magnetic resonance imaging was the preferred first-line diagnostic modality. Despite heterogeneity in several aspects of care, consistent patterns emerged. Accurate tibial tunnel positioning and restoration of full preoperative knee extension were considered the most critical preventive factors. Initial management was predominantly conservative, with most surgeons advocating an extension-focused rehabilitation trial before surgical intervention. Arthroscopic excision was generally reserved for persistent extension deficits and was associated with favorable outcomes and low recurrence rates. However, substantial variability persisted regarding the role of remnant preservation, timing of surgery, and indications for imaging, highlighting unresolved clinical controversies. While substantial variability exists in the management of cyclops syndrome after ACLR, consistent clinical patterns can be identified. Based on these findings, a stepwise management approach can be proposed, emphasizing early recognition of extension deficit, selective use of imaging, and a staged treatment strategy. These results provide a foundation for future efforts toward consensus guidelines and standardized care pathways. Level V, cross-sectional survey study.