The meniscofibular ligament: an MRI study.

AIM: To describe the appearances and determine the prevalence of the meniscofibular ligament (ligamentum fibulare-MFibL) on MRI of the knee.

SUBJECTS AND METHODS: Retrospective observational review of 160 knee MRI studies (152 patients) which was performed for a variety of clinical presentations over a period of 31 months. The images were assessed independently by two musculoskeletal radiology Fellows.

RESULTS: The MFibL was optimally visualised on far lateral sagittal oblique fat suppressed PDW FSE images. The MFibL appeared as a curvilinear or straight, hypointense band of variable thickness extending between the inferior margin of the posterior third of the lateral meniscus and the fibular head. The ligament was demonstrated in 42.5% (n=68) of the total knee MRI studies, but this prevalence increased to 63% (56/88) in the presence of fluid in the posterolateral corner of the joint.

CONCLUSION: The MFibL is commonly seen on far lateral fat suppressed oblique sagittal PD weighted MR images, particularly in the presence of fluid in the posterolateral corner, and should be recognised as a normal structure in the posterolateral corner of the knee.