Osteochondral lesions, also known as osteochondritis dissecans, are areas of damaged bone and cartilage on the surface of the ankle bone (the talus), usually caused by an ankle injury.
If you suffer an ankle sprain (or any kind of trauma to the ankle) and the cartilage fails to heal properly, bits of cartilage may break off and float around in the space between the bones in your ankle.
This kind of injury can sometimes lead to the formation of a cyst in the talus bone.
The area most directly affected by osteochondral lesions is the talar dome, which is the part of the talus that articulates with the tibia and fibula to form the ankle joint. The talar dome plays an important role in ankle motion and weight bearing.
What Are The Symptoms of Osteochondritis Dissecans?
Symptoms of osteochondritis dissecans may include:
- Recurrent ankle sprains, or a sprain that does not seem to heal
- A feeling of looseness or instability in the ankle
- Antalgic gait
- Ankle pain that does not go away and becomes worse with activity
- Catching or clicking sensation when walking
- Clicking or popping noises
If the lesions have been caused by an injury, there may be some tenderness in the injured spot, and the patient may experience pain when flexing the foot. In many cases, however, osteochondritis dissecans presents with no symptoms, and may go undiagnosed until it is noticed on an x-ray or MRI conducted for some other reason.
What are the Causes of Osteochondritis Dissecans?
Fractures of the talar dome are usually the result of inversion injuries—that is, an inward twisted ankle—and when injury is the cause of osteochondritis dissecans, it is usually this type of injury. Lesions that appear on the top outside part of the talus are most often caused by injury.
Medial osteochondral lesions, however (lesions on the inside part of the talar dome), can be caused either by injury or by chronic weight overload, which can be caused, in part, by very high arches, or by chronic ankle instability.
Risk Factors of Osteochondritis Dissecans To Know About
Osteochondral lesions are often caused by sprains or similar injuries, and therefore athletes and dancers are more at risk than the general population. To find out which sports may put you at greatest risk of osteochondritis dissecans, read our article about dangerous sports for your feet and ankles.
Complications of Osteochondritis Dissecans
It is important to get any ankle injury looked at by a doctor as soon as possible, as a long enough delay in obtaining treatment can potentially lead to long-term disability.
How is Osteochondritis Dissecans Diagnosed?
Osteochondral lesions of the talus are often missed by doctors treating rotational ankle injuries. CT scans or MRI (magnetic resonance imagining) may be necessary because often osteochondritis dissecans does not show up on x-rays.
Another problem is that many people ignore ankle sprains unless the pain persists for several weeks, and by the time a diagnosis is made, a cyst may have formed within the talus.
How is Osteochondritis Dissecans Treated?
Nonsurgical treatment of talar fractures usually involves keeping weight off the affected foot and wearing a cast. If lesions are present, however, further treatment will be necessary.
If the osteochondral lesion is stable—that is, if there are no loose pieces of bone or cartilage—then conservative, non-surgical treatment may be attempted. This usually consists of an ankle brace, or possibly a cast to completely immobilize the ankle.
The patient will be advised to take NSAIDs (non-steroidal anti-inflammatory drugs), and will undergo physical therapy after the lesion has healed in order to restore strength and range of motion.
If surgery is required, osteochondritis dissecans will often be addressed with ankle arthroscopy, a procedure involving the insertion into the ankle of a small flexible tube with a light, camera, and surgical instruments attached to it.
In severe cases of osteochondritis dissecans, it may be necessary to resort to a procedure known as bulk allograft transplantation, which involves taking bone and cartilage from a cadaver and grafting it into the damaged talus of the injured person.
This is only done when more conservative treatments have failed. Ankle fusion is also used in some cases, if the talus is very badly damaged.
How Can I Prevent Osteochondritis Dissecans?
The best way to prevent osteochondral lesions is to avoid sustaining serious ankle injuries. Wear appropriate shoes when playing sports or working with heavy machinery, and always exercise caution.