Osteochondral Injury of the Talus (Osteochondritis Dissecans, OcD)

The cartilage lining of the anklebone can be bruised when a sprain of the ankle occurs. As the anklebone (the talus) twists inside its box-like housing, the edge of the talus rubs up and hits the end of the tibia. This causes a bruise and leads to softening of the cartilage. It may lead to a small crack in the cartilage and a cyst forming in the talus bone. This we refer to as an osteochondral injury of the talus. An older term for this, which we do not use any longer, is called Osteochondritis Dissecans.

This is the typical appearance of an osteochondral injury of the talus. It is difficult to see on the X-ray.

These are MRI images of the ankle. The round black hole on the right MRI is typical of this problem.

There are many grades of severity of this osteochondral injury to the talus. Minor events lead to bruising of the talus. If the injury is more severe, large pieces of bone and cartilage can break off and lie loose in the ankle joint.

The treatment depends on the severity of the osteochondral injury. The more severe types require surgery. If bruising of the bone is present, resting the ankle may be all that is required to alleviate the process. Most of the time, however, the initial injury to the talus is not recognized early enough. By the time the diagnosis is made a cyst has formed in the talus itself. These cysts or osteochondral defects are invariably symptomatic and require treatment.

The treatment for an osteochondral defect of the talus is extremely varied and depends on the size of the defect and the extent of bone and cartilage loss. The simplest surgical treatment is arthroscopy. Multiple tiny punctures are made around the ankle. Through these punctures a small telescope is inserted and the inside of the joint becomes visible. Microscopic operative instruments are then inserted into the joint to clean out the cyst. There are other, more extensive surgeries that occasionally need to be performed. These can range from bone grafting to more sophisticated treatments in which portions of the talus have to be replaced using large grafts. These grafts can be obtained from the patient’s own body or from a cadaver. Recovery from these procedures depends upon the extent of the defect and whether it can be treated arthroscopically or through open means with grafting. If the defect in the talus is significant, the ankle may need to be fused to eliminate the pain.