Osteochondritis Dissecans

Osteochondritis dissecans is a joint condition in which a piece of cartilage, along with a thin layer of the bone separates from the end of the bone because of inadequate blood supply.  These fragments may be localized, or may detach and fall into the joint space causing pain and joint dysfunction.

Anatomy

The femoral condyles of the knee are most commonly affected. The two femoral condyles make up for the rounded end of femur (thigh bone). Each knee has two femoral condyles, the medial femoral condyle on the inside of the knee and the lateral femoral condyle on the outside of the knee. Osteochondritis dissecans occurs most commonly on the lateral aspect of the medial femoral condyle. The condition can also occur in other joints, including elbows, ankles, shoulders and hips.

Incidence

Osteochondritis dissecans is more common among boys and young men between 10 and 20 years who actively take part in sports Athletes participating in sports such as gymnastics and baseball may develop osteochondritis dissecans.

Causes

The exact cause of osteochondritis dissecans remains unknown, but factors such as trauma, fractures, sprains, or injury to the joint are considered to increase the risk of developing the condition. Osteochondritis dissecans may be caused by restricted blood supply to the end of the affected bone that usually occurs in conjunction with repetitive trauma. Following injury, the bone may be deprived of blood flow leading to necrosis and finally the bone fragment may break off.  Articular cartilage may become compressed, flattened, and a subchondral cyst can develop. All these changes ,in addition to increased joint pressure, can lead to failure of joint healing.

The appearance of osteochondritis dissecans in several family members may indicate that the condition is inherited.

Symptoms

Patients with osteochondritis dissecans usually have joint pain, swelling, stiffness, decreased range of motion, and joint popping or locking. Pain usually increases after activity.

Diagnosis

Dr. Fischer will likely start with an X-ray of both knees to see the abnormality in the joint space and to compare them. You will likely also benefit from an MRI to reveal the joint damage in more detail.

Treatment

Dr. Fischer will recommend treatment depending on the imaging results, age, severity, stability of the cartilage and your specific activity goals. Treatment is tailored to relieve the symptoms and stop or impede the progression of joint degeneration. Conservative treatment approaches such as protected weight bearing, pain medication, and joint stabilization are recommended if the condition is diagnosed at the early stages and if the condition is mild. However, surgery is required if the condition is diagnosed at advanced stage or if the condition is moderate to severe.

Surgical treatment of osteochondritis dissecans can be performed by open or arthroscopic techniques. Some of the surgical procedures include drilling, bone grafting, open reduction internal fixation, osteochondral grafting, or autologous chondrocyte implantation (ACI).

  • Drilling/Microfracture - In this method multiple small holes are drilled/tapped into the bone which stimulates the growth of new blood vessels in the defect area. This promotes blood flow into defect area thereby promoting the healing response and formation of new cartilage cells inside the lesion
  • Open reduction internal fixation - Open surgery is performed in cases where the affected area is difficult to reach with arthroscope or a relatively large fragment.  In this procedure, an incision is made in front of the joint to allow the surgeon to see the joint and the loose bodies are removed. Internal fixation involves fixing the fragments using internal fixation such as screws, pins, or wires
  • Osteochondral grafting - The procedure involves transfer of healthy cartilage plugs into the damaged areas of the joint. It allows the newly implanted bone and cartilage to grow in the defected area. Grafts may be taken from the same individual (auto graft) or from a donor (allograft)
  • Autologous chondrocyte implantation (ACI) - In this procedure healthy cartilage cells are harvested from the non-weight-bearing joint of the patient and cultured in the lab The cultured cartilage tissue will be implanted into the defected area which promotes the growth of new cartilage