Bifurcate ligament:
- This ligament connects the anterior process of the calcaneus to both the cuboid and navicular bones (indicated by green triangle in the image above)
- Inversion stress of the foot will result in stretch of this ligament or avulsion fracture of the anterior process.
- Often underdiagnosed by practioners outside of a foot and ankle specialty
SYMPTOMS:
- Pain to the outside middle portion of the foot
- Worse with pointing the foot downwards (plantarflexion) or rolling the foot outwards (supination)
DIAGNOSTIC EXAMS:
- Initial medial oblique x ray should be taken with every severe ankle sprain to rule out avulsion fracture of the anterior calcaneal process, especially when symptomatic over this specific region of the foot
- An MRI can confirm the diagnosis of bifucate ligament tear
TREATMENT:
- Most often immobilization with cast or CAM walker for at least 4 weeks is necessary, especially if ligament is torn
- Rarely is surgery indicated to reduce and fixate a displaced avulsion fracture of the anterior process of the calcaneus
- Physical therapy is usually required after immobilization to restore strength and balance to the injured foot and ankle