Clinical Report: Anatomical Variants of Knee Meniscus via 7-Tesla MRI
Overview
This prospective study utilized high-resolution 7-Tesla MRI to investigate anatomical variations of meniscal root insertions in asymptomatic adults. The study revealed intact meniscal roots in all evaluated knees, identified multiple insertion sites, and detailed meniscofemoral ligament anatomy with high inter-rater reliability.
Background
Menisci are critical for knee biomechanics, contributing to load distribution and joint stability. Meniscal root tears significantly disrupt knee mechanics and may accelerate osteoarthritis progression. Standard arthroscopy has limitations in visualizing posterior meniscal roots, making MRI an essential tool for detecting root lesions. The advent of 7-Tesla MRI offers enhanced spatial resolution and contrast, enabling detailed assessment of meniscal anatomy that was previously challenging to visualize.
Data Highlights
Parameter
Value
Participants
48 asymptomatic adults
Knees evaluated
57 (32 left, 25 right)
Mean age
32.2 ± 8.8 years
Meniscal tears observed
6 knees
Imaging sequence
3D double-echo steady-state (DESS)
Voxel size
0.20 × 0.20 × 0.24 mm³
Inter-rater reliability (Cohen's κ)
Strong to almost perfect
Key Findings
All 57 knees exhibited intact meniscal root insertions with no root tears detected on 7-T MRI.
Multiple meniscal root insertions were identified and precisely mapped using multiplanar reconstructions.
Meniscofemoral ligaments (anterior Humphrey and posterior Wrisberg) were consistently visualized and their attachments quantified.
High spatial resolution 7-T MRI enabled visualization of fine meniscal structural details, including hypointense signal with horizontal hyperintense striations.
Inter-rater reliability for anatomical assessments was strong to almost perfect, supporting reproducibility of findings.
Meniscal tears observed in six knees primarily affected the pars intermedia and posterior horn but did not involve root detachments.
Clinical Implications
The use of 7-T MRI provides enhanced visualization of meniscal root anatomy and meniscofemoral ligaments, which may improve detection and characterization of subtle meniscal pathologies. This imaging modality can aid clinicians and surgeons in preoperative planning by identifying anatomical variants and potentially occult lesions not easily seen with standard arthroscopy or lower-field MRI. Understanding these variants is crucial for accurate diagnosis and tailored treatment strategies to prevent progression of joint degeneration.
Conclusion
High-resolution 7-Tesla MRI is a valuable tool for detailed assessment of meniscal root anatomy and variants in asymptomatic individuals. Its superior imaging capabilities enhance anatomical mapping and may improve clinical evaluation of meniscal injuries.
References
Johannsen et al 2012 -- Arthroscopic landmarks for meniscal root repair
LaPrade et al 2015 -- Meniscal root anatomy and repair techniques
