Osteochondritis Dissecans (OCD) of the knee is a disorder in which fragments of bone break off from the knee joint surface. Unlike arthritis of the knee, the degeneration of the knee joint occurs quite quickly. It affects the articular cartilage (the smooth covering of the ends of bones) and subchondral bone (bone underneath the cartilage), which becomes separated from the rest of the bone. The fragments may be smooth and still sitting in their normal position - called a stable lesion - or it may become loosely attached to its bony base, or detach to become a loose body within the joint space - an unstable lesion.
At the present time, the cause of OCD remains uncertain but previous trauma and ischaemia (inadequate blood supply) have been implicated. OCD most commonly affects the knee, with other less common sites including the elbow and ankle.
80-85% of cases are reported to occur in the area of the knee called the Medial Femoral Condyle (the innermost part of the bottom of the thigh bone). 10-15% of cases occur in the Lateral Femoral Condyle, (the outermost part of the bottom of the thigh bone) and 5% of cases in the Patella (kneecap).
The incidence of OCD is reported at 30 to 60 cases per 100,000 people. The condition usually appears during the patient's teenage years (those who have OCD of the patella usually present later, in their 20s or 30s) but the disorder may appear in later life. However, the lesion is not always a cause of symptoms. 30-40% of patients will be affected in both knees, while males are 3 times more likely than females to develop OCD.
Patients with Osteochondritis Dissecans (OCD) of the knee usually have localised pain and swelling, which can also include the knee locking or giving way as the disease progresses. The knee pain can increase with strenuous activity and twisting motions and a particular form of OCD will exhibit a painful 'clunk' when bending or straightening the knee.
An X-ray should pick up the majority of OCD lesions if the correct views are taken (antero-posterior, lateral and tunnel views). An MRI scan is very useful in OCD management decisions because it helps determine the size and quality of the fragment and reveals information about fragment stability.
|Consult a sports injury expert|
|Apply ice packs/cold therapy|
|Wear a knee brace for protection|
|Use a buoyancy aid for pool exercises|
The goals of treatment for Osteochondritis Dissecans are to reduce pain, restore the continuity of the articular surface, and decrease the likelihood of future degenerative joint disease (osteoarthritis).
Treatment options are largely dependent upon the age of the patient and the position and stability of the lesion:
During surgery the knee specialist will examine the knee joint surface. Stable lesions will be left alone to heal, although unstable lesions may be surgically fixed back in place. Any loose bodies and bony fragments will be washed out.
Following surgery the knee pain and swelling can be minimised by using Ice Therapy. The Aircast Knee Cryo/Cuff is the most effective method of providing ice therapy and can be used for the home treatment of knee injuries and knee pain. It can provide continuous ice cold water and compression for 6 hours, to significantly reduce knee pain and knee swelling.
Rehabilitation is extremely important following surgery for Osteochondritis Dissecans. The exact instructions of the surgeon should be followed. This may require a period of restricted weight bearing, where impact exercises are not allowed. During this time, provided the surgeon sanctions it, knee function can be enhanced by performing non weight bearing exercises in the pool. The Aquajogger is a buoyancy belt that allows an early return to swimming pool exercises when there is an injury that would otherwise stop someone from exercising. It clips around the waist and keeps the feet off the bottom of the pool, allowing the user to run without putting weight through their injury.
There are no proven prevention strategies for Osteochondritis Dissecans.