fabellofibular

The fabellofibular ligament is a small fibrous band that forms part of the posterolateral corner of the knee. It connects the fabella, a sesamoid bone embedded in the tendon of the gastrocnemius muscle behind the knee, to the fibular head or lateral aspect of the knee. Its presence and appearance can vary among individuals and it is often considered a component of the posterolateral corner anatomy.

Anatomically, the ligament arises from the fabella if present and runs toward the fibula, where it may blend with surrounding structures such as the arcuate complex and the popliteus–fibular components. In some individuals, the fabellofibular ligament is absent or only variably developed. Because it is not consistently present in all knees, its contribution to stability is considered supplementary rather than essential.

Functionally, the fabellofibular ligament is thought to reinforce the posterolateral corner, helping to restrain external tibial rotation and varus stress, particularly in flexion. It works in concert with other PLC structures, including the popliteus tendon, the fibular collateral ligament, and associated ligaments, to maintain knee stability during rotational and lateral movements.

Clinical significance includes its involvement in posterolateral corner injuries, which may occur with knee trauma or dislocations. Diagnosis is typically by magnetic resonance imaging, and treatment depends on the pattern of PLC injury. The presence of the fabella and its ligament can influence surgical planning for PLC reconstruction in some cases.