Osteochondral defects(OCD) are very localised areas of joint damage. These conditions usually occur on the talus and are a region where the cartilage and underlying bone have been disrupted. How disrupted can vary from 'bruising' to a crater or deep defect on the surface of the joint, lacking the underlying bone as well as cartilage (See 'X section of idealised joint' in the anatomy section). These most often, though not exclusively, occur after some injury to the joint.
A posteromedial osteochondral defect(arrow) of the talus.
An MRI scan of the same defect
What sort of injury may result in an osteochondral defect?
A not uncommon history is that of a sprained ankle which has failed to settle and gives symptoms (pain/instability) long after it should (see 'The sprained ankle' section for a more comprehensive review of this problem).
How is this condition different from arthritis?
The changes in the joint surface are very localised (often widespread in arthritis), are almost always just on the talar side of the joint (usually on both sides of the joint in arthritis) and result in softening of the joint surface (usually significant hardening in arthritis).
What symptoms might I expect to have with a osteochondral defect?
Generally pain is the main symptom, on weight bearing and not infrequently when resting as well. It is not uncommon to also have feelings of instability from the joint.
Do I need to have an osteochondral defect treated ?
It is unclear if an OCD will necessarily progress to osteoarthritis or what its natural history is.
A decision to have treatment can be made on the basis of whether the patient has persisting and troublesome symptoms or not.