Non-traumatic avascular necrosis of the talus

Talar fractures are unfortunately all to common. Talar fractures can be quite debilitating and lead to a loss of career or limitations in activities. Talar fractures are a common sequelae of motor vehicle accidents and falls from a height. We see talar fractures in rock climbers and roofers.

One complication of a talar fracture is avascular necrosis (AVN). AVN occurs when the blood supply to the talus is disrupted. Avascular simply means no blood and necrosis means that the bone dies as a result of this loss of blood.

But AVN can also occur in the talus in the absence of trauma. I saw a case today of non-traumatic AVN in a pleasant 72 y/o housewife. She described a mild sprain several months ago but didn’t seem to relate the sprain to her current pain. Plain films were negative for change. MRI indicated extensive necrosis of the distal tibia and neck of the talus suggesting a dorsiflexion injury of the ankle.

AVN can occur at a number of locations in the body, most commonly the hip. Due to load bearing of the hip, fracture is a common outcome of AVN in the hip.

We know that the talus is particularly susceptible to AVN due to the fact that it is 3/5 covered with cartilage. This cartilage makes up the joint surfaces of the ankle and subtalar joints. And anywhere we find cartilage, we cannot have a blood vessel enter the bone. Therefore, the more cartilage, the less vascular inflow and increased risk for AVN.

But without a history of trauma, how does AVN occur? A direct correlation between steroid use and AVN of the hip is found in the literature. Why steroids? We’re not really sure. Occlusion by embolis is another possibility. But I think we have a lot to learn about the etiology of non-traumatic AVN.

We’ll keep this patient partial weight bearing in a walking cast and keep her on a walker. She knows that it’ll be a number of months before I feel comfortable with her bearing full weight on the foot. She also realizes that as the AVN progresses, the possibility of collapse of the talus ever present.

Jeffrey Oster, DPM
Medical Director
Myfootshop.com

Treatment for avascular necrosis of the sesamoids.

Avascular necrosis, also called AVN, describes the loss of blood flow to a particular area of bone. The sesamoid bones are often effected by ANV and can have varying degrees of pain. What’s the best course of treatment? Join us in this discussion for more information.

Jeff Oster, DPM
Medical Director
Myfootshop.com