What are osteochondral defects?
These are localised areas of damage to the cartilage surface of the knee joint. It’s like a pothole on an otherwise good road surface, unlike (osteo)arthritis which is like a worn road surface. The bone underneath the region of cartilage can also be damaged. Focal cartilage defects can be caused by trauma, repetitive overload and are often associated with ligament injuries. Cartilage injuries usually do not heal spontaneously and can worsen over time.
What are the symptoms of osteochondral defects?
These injuries tend to cause pain and swelling but can sometimes be pain-free. If a fragment of cartilage breaks away it can float around in the knee and cause a sudden painful limitation in knee movement, known as “mechanical locking”.
How are osteochondral defects diagnosed?
Usually the symptoms and a careful examination will suggest the diagnosis. This is usually confirmed with an x-ray or MRI scan. Sometimes a CT scan can be helpful.
How are they treated?
Very small areas of damage that aren’t causing many symptoms can be managed with over the counter pain killers and exercises under the guidance of a physiotherapist. Impact activities should be avoided. Weight loss can be helpful. Unfortunately, larger symptomatic defects often require surgery. The options are dictated by the size and location of the injury: smaller areas are treated by techniques such as microfracture or osteochondral plug transfer; larger areas are treated by techniques such as autologous chondrocyte implantation or stem cell therapy. An alternative is to use a small metallic or polymer implant to resurface the defect. Whichever treatment is chosen, it is very important to assess and address underlying knee problems such as abnormal leg alignment, ligament instability or significant loss of meniscal tissue. These issues could increase the chance of failure of treatment and could have contributed to the cartilage injury in the first place.