Magnetic resonance arthrographic dissection of posterolateral corner of the knee: revealing the meniscofibular ligament.
OBJECTIVE
To evaluate meniscofibular ligament (MFibL) at the posterolateral corner of the knee joint on the magnetic resonance arthrography (MRA) with 70° knee flexion.


METHODS
The MRA of the knee joint was performed at 70° knee flexion. Eighteen patients (19 knee joints) underwent scanning of sagittal, coronal, and axial fat-suppressed T1 weighted images (T1FS), and coronal fat-suppressed T2 weighted images. Sagittal three-dimensional (3D) gradient echo (GRE) images were also obtained. Retrospective review of 19 knee MRA studies was independently performed by two musculoskeletal radiologists. The statistical significance was proved by chi-square test.


RESULTS
The MFibL ligament was optimally demonstrated on the far lateral sagittal 3D GRE and T1FS MRA images. The MFibL appeared as a curvilinear or straight hypointense band of variable thickness, extended from the posterolateral meniscus to upper anteromedial aspect of the fibular head. The MFibL was demonstrated with scale 2 (more than a half length of the ligament) by both reviewers in 73.68% (n=14/19) of the knee 3D GRE images and 89.47% (n=17/19) of the knee T1FS images. The visualization on T1FS and that on GRE were not statistically different from each other (p>0.05). The interobserver agreements were significantly good on both 3D GRE and T1FS images in detecting the ligament (kappa values, 0.642 and 0.683, respectively).


CONCLUSIONS
The MFibL is well visualized on the far lateral sagittal MRA at 70° knee flexion, which could potentially be useful in recognizing structures in the posterolateral corner of the knee, including the MFibL.
Department of Radiology, Research Institute of Radiological Science, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Young Han
YH
Lee
Ho-Taek
HT
Song
Sungjun
S
Kim
Sung-Jae
SJ
Kim
Jin-Suck
JS
Suh
D000328:Adult; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008022:Ligaments / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055815:Young Adult