Cyclops syndrome following ACL reconstruction: a complex issue that extends beyond mechanical obstruction

Esteban Andres Lobos Centeno; Pierre Chambat; Johannes Barth

DOI: 10.70885/hmsj.2025.01.001

Abstract

Hypothesis: We hypothesized that cyclops syndrome represents a mechanical issue, suggesting that the problem (extension deficit) is definitively resolved and solved once the cyclops is removed.Materials and Methods: During a two-year period (from January 1992 to December 1994), in which 835 bone-patella-bone autograft ACL reconstructions were performed, 36 patients (4.3%) required arthroscopic revision for Cyclops lesions. The mean age of patients was 26.2 years old (range, 16-43 years). Average time of treatment of the Cyclops lesion after primary surgery was 10 months (range, 2.5-26 months). Activity level was intensive for most of the patients. All patients were evaluated with the IKDC scoring system (subjective evaluation and clinical exam) and KT 1000 testing. Residual Cyclops symptoms were also analyzed. The mean follow-up was 9 years (range, 8-10 years).Results: Seven patients were lost to follow-up and were excluded from the study. Twenty-nine patients were followed up: 6 by phone (16.7%) and 23 clinically (63.9%). Two recurrent ACL lesions were noticed (6.9%). The mean final IKDC subjective score was 81.6 points (range, 50-100). Half of the patients had good results (greater than 82 points), while the other half had reduced scores (between 50 to 80 points). The distribution of the final IKDC objective score was: A = 17.4%; B = 65.2%; C = 8.7%; D = 8.7%. Thirteen patients had persistent Cyclops symptoms (44.8%), 14 patients still had loss of motion (48.3%), and 15 patients had diminished levels of activity (51.7%).Conclusions: Cyclops syndrome, while not affecting knee laxity, is associated with significant long-term symptoms. This suggests a complex etiology beyond mechanical factors. Early surgical intervention may mitigate chronic complications.Type of Study: Retrospective clinical studyKeywords: cyclope/ ACL complication / Arthrogenic Muscle Inhibition (AMI) / extension deficit/ kneehttps://doi.org/10.70885/hmsj.2025.01.001

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