Plantar Fascia Lateral Fascicle Rupture: How Severe Can It Be?

The plantar fascia is a thick and strong group of longitudinal and transverse bands of collagen-rich tissue, consisting of central, medial, and lateral fascicles. Biomechanically, the central fascicle assumes a special role in medial longitudinal foot arch preservation. However, there is scarce data on plantar fascia medial and lateral fascicles' anatomy and pathology in the literature. We report the case of a 27-year-old male professional soccer player who presented with sudden-onset, severe lateral right rearfoot pain that had started while doing linear sprinting practice. The athlete had no relevant medical history and no history of previous right foot injuries. The radiographic study of the right foot revealed no significant changes. MRI showed a high T2 signal partially interrupting the plantar fascia lateral fascicle low signal, consistent with a lateral fascicle rupture. The rehabilitation program was initiated and included pharmacological and non-pharmacological management. He experienced an extremely favorable evolution of his condition with the absence of pain and partial weight bearing in less than one week, with a full return to sports in approximately two weeks. During dynamic foot movement, the lateral fascicle seems to be less biomechanically recruited compared to the central one; however, the strain is not negligible and might be the reason for the pathology. Still, this slightly decreased strain might explain this injury's faster healing time compared to that associated with the central fascicle. Regarding the risk factors for plantar fascia ruptures, it should be kept in mind that a tear might occur even in their absence. We intend to raise awareness about the existence of plantar fascia lateral fascicle and the possibility of associated pathology, either acute or chronic. Hopefully, in the near future, plantar fascia ruptures will get significantly more attention in the literature, enabling the creation of proper management guidelines.