The CFL is the second lateral ankle ligament to fail in ankle sprains, torn in Grade II-III injuries. Unlike the ATFL, the CFL crosses both the ankle and subtalar joints, providing combined talocrural and subtalar stability. It runs deep to the peroneal tendons and their sheath — CFL tears are associated with peroneal tendon sheath tears in Grade III sprains. The talar tilt test assesses CFL integrity.
| Origin | Inferior tip of the lateral malleolus (just anterior to the PTFL origin) |
|---|---|
| Insertion | Lateral calcaneus (lateral surface — to the peroneal tubercle area) |
| Actions | Primary restraint against talar tilt in the neutral and dorsiflexed positions; crosses both the ankle and subtalar joints providing stability to both |
|---|
CFL integrity assessment: the talar tilt test under local anaesthesia or fluoroscopic stress radiography shows increased talar tilt (greater than 10 degrees or more than 5 degrees compared with the opposite side). MRI confirms CFL tear as absence of the normal fibular to calcaneal ligament with surrounding oedema. Brostrom-Gould repair addresses both ATFL and CFL simultaneously.
Grade III lateral ankle complex tear involving CFL and peroneal tendon sheath requiring assessment for concurrent peroneal tendon pathology during Brostrom repair.
