Summary

Identification of modifiable risk factors to prevent the Cyclops syndrome after the ACl reconstruction

Abstract

Background

The Cyclops syndrome represents a possible complication of the anterior cruciate ligament reconstruction (ACL) and consists of the development of a fibrous nodule anterior to the graft leading to femoral impingement with subsequent knee lack of extension and pain. This condition frequently requires a second knee arthroscopy to perform the debridement of the lesion in order to restore the complete functionality of the knee. Identifying modifiable risk factors could help reduce the incidence of the disease and, thus, the morbidity and the reoperations after ACL reconstruction.

Purposes
The present study aims to investigate the prevalence of Cyclops syndrome and to identify demographical and surgical risk factors leading to the disease.

Methods

Patients who underwent primary ACL reconstruction in a single Institution specialized in sports medicine between 2018 and 2022 were retrospectively included in the study. Patients with symptomatic Cyclops were defined as the ones who experienced knee pain or lack of extension and an MRI showing fibrous tissue anterior to the graft. The analyzed risk factors were: sex, age, pre-operative body mass index (BMI), side of injury, activity level, time injury to surgery, duration of the surgery, type of graft, graft diameter, type of femoral and tibial fixation, recourse to lateral extra-articular augmentation, meniscal tear, type of meniscal treatment, use of brace, brace duration, delayed weight bearing, type of deep venous thrombosis prophylaxis and duration. The statistical analysis was performed through a preliminary univariate analysis based on the Student t-test for continuous normal distributed variables and Chi-square test for categorical variables and a final logistic regression analysis to confirm the findings and evaluate the Odds Ratio (OR) of the single factors identified.

Results

A total of 586 patients were included in the final analysis. The symptomatic cyclops were 60 (10%); the main symptoms leading to the diagnostic MRI were lack of extension (n=27; 45%), pain (n=29; 48%), and a combination of the previous two (n=3; 5%). The reoperations were 35 (58% of the symptomatic cyclops; 6% of the population). The final identified risk factors were the use of a brace regardless of the duration (p= .003; OR 2.57, 95%CI 1.38-4.77) and the BMI (p= .004; OR 1.08, 95%CI 1.03-1.15).

Conclusions

The use of a brace after ACL reconstruction and a higher pre-operative BMI are risk factors for Cyclops syndrome.