Risk Profile for Cyclops Syndrome Necessitating Reoperation After Anterior Cruciate Ligament Reconstruction

Area of Science:

• Orthopedic surgery
• Sports medicine
• Biomechanics

Background:

• Cyclops syndrome, a complication of anterior cruciate ligament reconstruction (ACLR), causes loss of knee extension and may require revision surgery.
• Limited understanding exists regarding patient risk factors for developing cyclops syndrome post-ACLR.

Purpose of the Study:

• To define the risk profile of patients predisposed to reoperation for cyclops syndrome after primary ACLR.
• To identify independent predictors of cyclops syndrome development.

Main Methods:

• A case-control study analyzed 1163 primary ACLRs performed between 2014 and 2021.
• Data collected included patient characteristics, graft details, surgical factors, and posterior tibial slope (PTS).
• Univariate and multiple regression analyses identified risk factors associated with reoperation within 24 months.

Main Results:

• The overall reoperation rate for cyclops syndrome was 5.5%.
• Contralateral knee hyperextension and a PTS >12° were identified as potential risk factors on univariate analysis.
• Knee hyperextension emerged as an independent predictor for reoperation (OR, 2.40; P = .049) after controlling for other variables.

Conclusions:

• Contralateral knee hyperextension is an independent predictor for cyclops syndrome requiring surgical debridement after primary ACLR.
• Factors such as surgical delay, graft type/diameter, meniscal repair, remnant preservation, and graft impingement were not associated with reoperation for cyclops syndrome.