How does it feel?
Generally pain will be felt when the ankle bears weight but can also be painful at rest. It may often result from a sprained ankle which has failed to settle, creating long term pain and instability. Osteochondral defects(OCD) are very localised areas of joint damage. Unlike arthritis the damage exhibits as joint surface softening, rather than arthritic hardening.
These conditions usually occur on the talus and are a region where the cartilage and underlying bone have been disrupted, usually after injury. The degree of disruption can range from 'bruising' to a crater or deep defect on the surface of the joint, lacking the underlying bone as well as cartilage.
An OCD may or may not progress to osteoarthritis and a decision to have treatment will depend upon just how persistent and painful your symptoms may be.
What is an OsteoChondral Defect?
An osteo chondral defect is a very localised area of joint damage. This involves both the underlying bone (osteo) as well as the overlying cartilage (chondral). In the ankle an osteo chondral defect usually occurs on the talus. The characteristic areas are either antero-medial (on the inner side of the ankle and to the front) or postero-lateral (to the outer side of the ankle and to the back)
What Symptoms Might I Expect From an Osteo Chondral Defect
Generally pain is the main symptom. This is usually on weight bearing and usually, though not always, is localised to the side of the joint on which the osteo chondral defect exists. It is also not uncommon to have feelings of instability from the joint, despite the fact that there may be no actual laxity of the normal restraints. This is known as functional instability.
What Treatments are Available For Osteo Chondral Defects?
The treatments available are either non-operative, debridement and drilling of the defect or cartilage transplantation.
Non-operative management involves restricting activities not weight bearing. This may require the use of a plaster cast or an Aircast walking boot and may need to be worn for up to four months. This type of management is really only appropriate for very minimal cartilage and bone changes and only really if they have been detected early. In such early cases the chance of success is in the region of 40-50%.
Arthroscopic Debridement and Micro Fracture of Osteo Chondral Defects
This is the first line of treatment for most osteo chondral defects. Once the defect has been diagnosed with an MRI scan it is important to know that following this operative treatment you will be non-weight bearing on the affected ankle for six weeks and will be restricted in terms of sporting activity for five months.
Using a standard ankle arthroscopy, performed as a day case surgery, the defect is better assessed. Very occasionally a fragment of bone and cartilage exists as a single well defined piece which can be fixed back into place with an absorbable pin. More commonly this technique is not technically possible and there are many loose fragments in the base of the defect with a detached piece of cartilage and possibly some bone. Any loose fragments of bone and any other material within the defect are best removed arthroscopically and then the base of the defect drilled arthroscopically with fine wires or micro fractured.
A talar osteochondral defect. The normal cartilage rim(1), underlying healthy subchondral bone(2, after the defect has been debrided) and pick tool for microfracturing(3).