What is 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. The separated fragments are sometimes called “joint mice”. These fragments may be localised, or may detach and fall into the joint space, causing pain and joint instability.
Osteochondritis dissecans can occur in any of the joints including your elbows, ankles, shoulders and hips.
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 of osteochondritis dissecans
The exact cause for osteochondritis dissecans remains unknown and certain 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 the injury or trauma, the bones in the area may be deprived of blood flow, leading to necrosis and finally, the bone fragment may break off. This may initiate the healing process; however, by this time, articular cartilage will be compressed, flattened and a subchondral cyst will be developed. All these changes, in addition to increased joint pressure, cause failure in the healing of the joint.
Symptoms of osteochondritis dissecans
Patients with osteochondritis dissecans usually have elbow joint pain, swelling, stiffness, and decreased range of motion. Pain usually increases after activity.
Diagnosis of osteochondritis dissecans
Your doctor will probably order an X-ray of both the right and left elbow to look for any abnormality in the joint space. You may also have a CT or MRI scan that is useful in determining the location of loose fragments within the joint.
Treatment of osteochondritis dissecans
Your physician may recommend various treatments depending on the reports of the diagnostic scans, age, severity, stability of the cartilage and other factors. Goals of treatment are to relieve the symptoms and stop or impede the progression of degeneration of the joint. Conservative treatment approaches, such as wait and watch approach, pain medications and immobilisation for 1-2 weeks are recommended if the condition is diagnosed at an early stage and if the severity is mild. However, surgery is required if the condition is diagnosed at an advanced stage or if the condition is severe.
Surgical correction of osteochondritis dissecans can be done by open an approach or arthroscopic technique. Some of the surgical procedures include drilling, bone grafting, open reduction internal fixation, osteochondral grafting or autologous chondrocyte implantation (ACI).
- Drilling: In this method, multiple small holes are drilled into the bone to allow the growth of new blood vessels in the defect area. This promotes blood flow into the defect area, thereby initiating the healing response and formation of new cartilage cells inside the lesion.
- Open reduction internal fixation: Open surgery is performed in cases where the defective area is difficult to reach with an arthroscope. Hence, an open incision may be required. In this procedure, an incision is made in front of the joint to allow the surgeon to view the joint and the loose bodies are removed. Internal fixation involves fixing the fragments using internal fixators such as metal screws, pins or wires.
- Bone grafting: It helps to fill the gap after the removal of the dead or necrotic bone. In this procedure, bone graft is placed on the damaged site. This procedure may be performed to repair the damaged area or replace the missing bone. Autograft (harvested from the same individual) or allograft (taken from a bone bank) may be required to help in the growth of a new bone.
- Osteochondral grafting: The procedure involves transferring healthy cartilage plugs from non-weight bearing areas of the joint and transferring them into the damaged areas of the joint in a mosaic pattern. It allows the newly implanted bone and cartilage to grow in the defected area. Grafts may be taken from the same individual (autograft) or from a donor or bone bank (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 laboratory. The cultured cartilage tissue patch will be implanted into the defected area, which promotes the growth of new cartilage.