Osteochondritis dissecans (os-tee-o-kon-DRY-tis DIS-uh-kanz) is a joint condition in which a piece of cartilage, along with a thin layer of the bone beneath it, comes loose from the end of a bone.
Osteochondritis dissecans occurs most often in young men, particularly after an injury to a joint. Osteochondritis dissecans is most common in the knee. But, osteochondritis dissecans can occur in other joints.
If the loosened piece of cartilage and bone stays close to where it detached, you may have few or no symptoms of osteochondritis dissecans, and the fracture may heal by itself. Surgical repair may be necessary if the fragment comes loose and gets caught between the moving parts of your joint, or if you have persistent pain.
Signs and symptoms of osteochondritis dissecans may include:
Pain. The most common symptom of osteochondritis dissecans, pain may be triggered by physical activity — walking up stairs, climbing a hill or playing sports.
Joint popping or locking. Your joint may pop or get stuck in one position if a loose fragment gets caught between bones during movement.
Joint weakness. You may feel that your joint is "giving way" or weakening.
Decreased range of motion. You may be unable to straighten your leg or arm completely.
Swelling and tenderness. The skin around your joint may become swollen and tender.
When to see a doctor
If you have persistent pain or soreness in your knee, elbow or another joint, see your doctor. Other signs and symptoms that should prompt a call or visit to your doctor include joint swelling or an inability to move a joint through its full range of motion.
The exact cause of osteochondritis dissecans is unknown. It may be caused by a reduction of blood flow to the end of the affected bone. This may occur from repetitive trauma — small, multiple episodes of minor unrecognized injury that damage the end of the affected bone. There may also be a genetic component involved, making some people more inclined to develop the disorder.
Age. Osteochondritis dissecans occurs most often in people between the ages of 10 and 20, with the average age around 11.
Sex. Males are more likely to develop osteochondritis dissecans than are females.
Sports participation. Sports that involve jumping, throwing and rapid changes in direction may increase your risk of osteochondritis dissecans.
Osteochondritis dissecans can increase your risk of eventually developing osteoarthritis in that joint.
Adolescents participating in organized sports may benefit from education on the risks to their joints associated with overuse. Learning the proper mechanics and techniques of their sport and participating in strength training and stability training exercises may help reduce the chance of injury.
While you may first consult with your family doctor, he or she may refer you to a doctor who specializes in sports medicine or orthopedic surgery.
What you can do
Before your appointment, you may want to write a list that answers the following questions:
What joint symptoms are you experiencing?
When did this problem begin?
Does anything make your symptoms better or worse?
Have you injured that joint? If so, when did the injury occur?
Do you play any sports? If so, which ones?
What to expect from your doctor
During the physical exam, your doctor will press on the affected joint, checking for areas of swelling or tenderness. In some cases, you or your doctor may be able to feel a loose fragment floating around inside your joint. Your doctor will also assess the status of other structures around the joint, such as the ligaments.
Your doctor will also ask you to move your joint in a variety of different directions, to see if the joint can move smoothly through its normal range of motion.
X-rays. X-rays can show abnormalities in the joint's bones. Your doctor may recommend that both joints be X-rayed (both the right and left knee, for example) to compare them.
Magnetic resonance imaging (MRI). Utilizing radio waves and a strong magnetic field, MRIs can provide detailed images of both hard and soft tissues. Doctors frequently use MRI to help decide whether healing will occur with conservative treatment or whether surgery is necessary. Because MRI can produce detailed images without radiation exposure, it's the preferred test for osteochondritis dissecans.
Computerized tomography (CT). This technique combines X-ray images taken from many different angles to produce cross-sectional images of internal structures. CT scans can visualize cartilage as well as bone. This is useful in pinpointing the location of loose fragments within the joint.
Treatment of osteochondritis dissecans is intended to restore the normal functioning of the affected joint and to relieve pain, as well as reduce the risk of osteoarthritis. No single treatment works for everybody. In children whose bones are still growing, the bone defect may heal with a period of rest and protection.
Initially, your doctor will likely recommend conservative measures, which may include:
Resting your joint. Avoid activities that put stress on your joint, such as jumping and running. You may need to use crutches for a time, especially if pain causes you to limp. Your doctor may also suggest wearing a brace to immobilize the knee for a few weeks.
Physical therapy. Most often, this therapy includes stretching and range-of-motion exercises, and strengthening exercises for the muscles that support the involved joint. Physical therapy is commonly recommended after surgery too.
If conservative treatments don't help after three to six months, you may need surgery to remove loose fragments or to reattach fragments to the bone. Depending on the size of the fragment, or the tiny fractures in the bone underlying the fragment, surgery may be used to try to fill in the defect with cartilage containing bundles of collagen fibers (fibrocartilage). In many cases, these procedures can be performed arthroscopically — by inserting a fiber-optic camera and surgical tools through small incisions around the joint.
The newest procedure uses the person's own bone marrow to help rebuild the damaged area in the knee. New tissue quickly begins to grow to fill in the space where the bone fragment was removed.