1. The Talus Is the Key to the Ankle Joint
The talus sits between the heel bone (calcaneus) and the end of the legs bones (tibia and fibula). It is crucial to the function of the ankle. The tibiotalar joint moves the ankle up and down. The top of the talus bone is shaped like a dome, which allows it to flex and extend within the mortise joint formed by the ends of the tibia and fibula. The subtalar (below the talus) joint allows the calcaneus to move sideways below the talus. The two joints help you to walk on uneven ground, by providing a shock-absorbing function.
2. The Talus Is Covered Mostly with Cartilage
Cartilage covers bones and allows smooth motion. The talus is covered mostly with cartilage to allow a great deal of movement around it. This is why talus fractures are so devastating: the bone breaks, but there is often cartilage injury as well. Sometimes there are divots formed, sometimes the cartilage is scratched up by the sharp fracture ends, and sometimes the cartilage is peeled off (delaminated). This affects the motion of the tibiotalar and subtalar joints.
3. The Talus Has an Odd Blood Supply
Because the talus is covered with so much cartilage, there are very few places where a blood vessel can get into the bone. The talus is odd in that it has a retrograde blood supply. Most bones get their blood supply from nutrient arteries which enter the part of the bone closest to the heart (anterograde). A few bones in the body get their blood supply from arteries which enter the bone further away from the heart. However, because of this, the part of the bone closer to the heart is vulnerable to disruptions in blood supply that can happen with fractures. When this happens, this can result in avascular necrosis. This is a condition in which the bone dies because the blood supply is cut off.
4. Talus Fractures Rarely Can Be Treated Without Surgery.
It is crucial to line up the pieces of a talus fracture, because of its important function in motion and because of the tenuous blood supply. Rarely can this type of fracture be treated with a cast. The fracture must be non-displaced, otherwise the joint surfaces will not be smooth. Even with treatment in a cast, the fracture should be x-rayed fairly frequently to make sure it does not begin to shift.
5. Most Talus Fractures Need Screws
Typically, talus fractures need surgery to place screws across the fracture site. They may be placed from the front or back of the ankle. You will need to be on crutches for at least eight to twelve weeks, during which you cannot put weight on the ankle.
