Association of Mucoid Degeneration of the ACL with Medial Tibiofemoral Osteoarthritis Progression at MR Imaging

Abstract Background Using MRI, ACL mucoid degeneration is defined as a thickened ACL with increased signal intensity on all MR pulse sequences, with discrete fibers easily distinguished on fatsaturated T2-weighted or fat-saturated proton-density (PD)-weighted images but poorly differentiated on T1-weighted or non-fat-saturated PD-weighted images. Objective To assess the prevalence of ACL mucoid degeneration in a population of patients referred for routine knee MRI, and its association with age and structural joint damage. Patients and Methods Our study is a retrospective study conducted at the radiology department of Ain Shams University hospitals and Ain Shams University Specialized Hospital including 81 cases of knees with ACL mucoid degeneration by MRI and no sex predilection. Cases and controls were scored with respect to independent articular features: cartilage signal and morphology, subarticular bone marrow abnormality, subarticular cysts, subarticular bone attrition, marginal osteophytes and medial meniscal integrity. Results Patients with ACL mucoid degeneration were older than patients with a normal ACL, without statistically significant sex difference. Knees with ACL mucoid degeneration had statistically significant medial meniscal injuries and cartilage damage involving the central and posterior MTFC compared to control knees with a normal ACL frequency matched for age, sex and MR field strength. Conclusion Our study proved that there is a strong association between ACL mucoid degeneration and cartilage damage in MTFC.