Osteochondritis Dissecans
Introduction
Osteochondritis Dissecans is a condition in which the area of bone just under the Cartilage surface is injured, leading to damage to the blood vessels of the bone. Without blood flow, the area of damaged bone actually dies. This area of dead bone can be seen on an X-ray and is sometimes referred to as the Osteochondritis lesion.
The lesions usually occur in the part of the Joint that holds most of the body's weight. It is more common for the lesions to occur on the medial Femoral Condyle, because this is the part of the Knee which bears more weight. This area is under constant stress and doesn't get time to heal.
Pathophysiology:
- Avascular subchondral bone necrosis
- Articular fragments may also separate
Salient Features:
- Incidence : 30 to 60 per 100,000
- Bilateral Knee involvement in 30 to 40%
- Males affected 3 times more often than females
- Peak incidence
- Children under age 12 years
- Young adults
- Often missed at time of injury when it occurs and may be found later on x-ray
Clinical Features:
- Knee pain
- Morning stiffness in Knees
- Knee locking, catching
- Effusion
- Quadriceps atrophy
- Tenderness at affected Femoral Condyle
Special Test :
Wilson’s Test:
- Indication
- Assessment Knee OCD of medial Femoral Condyle
- Technique
- Examiner positions Knee in 90 degrees flexion
- Examiner internally rotates Tibia
- Patient slowly extends Knee
- Interpretation: Positive for Knee OCD
- Pain worse on Knee Extension to 30 degrees flexion
- Pain relieved with external rotation of Tibia
Investigations:
Conservative Management:
- Rest initially for 2-3 weeks
- Knee immobilization
- Non weight bearing
- Modify activity level from 3 weeks to 12 weeks
- Avoid rapid or strenuous activity (High Impact)
- Running
- Cutting
- Jumping
- Isometric quadriceps exercises
- Anticipate healing over time
Criteria for return to full activity
- No pain
- Normal physical exam
- X-ray shows signs of heeling
Surgical Management :
If the lesion becomes totally or partially detached, surgery is needed to remove the loose body or to fix it in place.
Arthroscopic Method
In most cases, the procedure is done by Arthroscopy.
Open Method
In some cases open surgery may be required when it difficult to fix the fragment arthroscopically.
Fragment Repair
Repair has the best results only if done early within 3 weeks of the injury. If the loose bone fragment is in a weight bearing area of your bone, your surgeon will try to reattach it if at all possible. Your surgeon may use tiny metal pins or screws to hold the fragment in place.
Osteochondral Autograft
An Autograft is a procedure for grafting tissue from the patient's own body. The place where the graft is taken is called the donor site. In this case, surgeons graft a small amount of bone (osteo) and Cartilage (chondral) from the donor site to put into the lesion. Usually, the donor site for this procedure is on the Joint surface of the injured Knee. Surgeons are careful to take the graft from a spot that won't cause a lot of problems, usually on the top and outside border of the Knee Cartilage.
Autologous Chondrocyte Implantation
A new technology called Autologous Chondrocyte implantation is currently being developed. It involves using Cartilage cells (chondrocytes) to help regenerate Articular Cartilage. This technology looks promising for treating JOCD and OCD but is still very much experimental.