Definition
Osteochondral lesions (OCLs), also called osteochondral defects (OCDs), are areas where significant damage has occurred to the joint surface (articular cartilage) of the talus, often involving the underlying bone. They may cause pain, usually felt deep within the ankle, as well as stiffness, swelling and locking or catching of the ankle joint. Most OCLs are thought to be cause by injuries such as ankle sprains, especially if they are on the lateral (outer) side of the joint. Some, however, appear without injury.
Diagnosis
Your doctor may suspect an OCL of the talus on the basis of your symptoms and tenderness of the ankle. It is, however, difficult to make the diagnosis on clinical grounds alone and usually an MRI scan is required. The scan also gives information about the size and type of the OCL. CT scanning can also provide useful information, particularly if there is bone involved.
Conservative Treatment
Talar OCLs that do not cause symptoms do not necessarily require treatment, although follow-up may be advised. How these lesions develop in the long term is not well understood.
Conservative treatments aim to offload the lesion in order to help it to heal. These include the use of crutches or boots, physiotherapy and injections of steroids or platelet rich plasma.
Surgical Treatment
The main surgical treatment of talar OCLs is usually performed arthroscopically (keyhole).
If the lesion is very new it is sometimes possible to fix it back to the main talus bone.
If this is not possible, and for older lesions the damaged cartilage is removed and the underlying bone marrow stimulated to encourage it to heal the defect. This is usually done by microfracture: punching small holes through the floor of the lesion and into the bone marrow. These techniques have shown good results in up to 85% of cases in recent studies.
If they prove unsuccessful different forms of cartilage transplant using the patient’s own cells (such as OAT mosaicplasty, ACI and MACI) may be of benefit although these techniques are not suitable for all patients or for all types of OCL. Your surgeon will be able to discuss whether or not they may be appropriate for you.