Objectives: To assess (i) normal imaging anatomy of the popliteomeniscal fascicles, (ii) prevalence and natural evolution of popliteomeniscal fascicle tears (PMFT) in subjects with traumatic anterior cruciate ligament (ACL) tears over 2 years and (iii) compare knee cartilage degeneration in subjects with and without PMFT longitudinally.
Methods: 57 subjects with ACL tears were screened for PMFT. Morphological (high-resolution 3D fast spin-echo) and compositional (T1ρ and T2 mapping) MR imaging was performed prior to and 2 years after ACL reconstruction. Differences of morphological and compositional parameters were compared between subjects with and without PMFT using logistic regression, adjusting for age, sex and BMI.
Results: In 24% (n = 14) of the subjects with ACL tear a PMFT was detected on baseline MRI. One subject with PMFT developed a meniscal tear over 2 years. Cartilage ∆T1ρ of the lateral femur increased significantly more in subjects with isolated PMFT compared to controls (mean difference, 2.0 ± 2.9 vs. -1.3 ± 1.6, p = 0.027).
Conclusion: PMFT detected by MRI are a common finding in subjects with ACL tears. Subjects with these defects showed higher compositional cartilage deterioration compared to controls, over 2 years in the lateral femoral compartment, indicating accelerated cartilage degeneration.
Key points: • Popliteomeniscal fascicle lesions are a common finding in subjects with ACL tears. • Progression to a meniscal tear over 2 years is not frequent. • Anteroinferior popliteomeniscal fascicle is injured most frequently. • Patients with popliteomeniscal fascicle lesions showed accelerated cartilage degeneration.
Keywords: Anterior cruciate ligament injuries; Cartilage; Magnetic resonance imaging; Meniscus; Popliteomeniscal fascicle.