Many parents face this challenge of a noncompliant child who has osteochondritis dissecans (OCD). There’s a very good chance that healing can occur when treated with nonoperative care. But that does mean limiting activities — especially weight-bearing, high-impact, twisting, and turning.
OCD mostly affects the femoral condyles of the knee. The femoral condyle is the rounded end of the lower thighbone, or femur. Each knee has two femoral condyles, referred to as the medial femoral condyle (on the inside of the knee) and the lateral femoral condyle (on the outside). Like most joint surfaces, the femoral condyles are covered in articular cartilage. Articular cartilage is a smooth, rubbery covering that allows the bones of a joint to slide smoothly against one another.
The problem occurs where the cartilage of the knee attaches to the bone underneath. 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. This means that the problem area is under constant stress and doesn’t get time to heal. It also means that the lesions cause pain and problems when walking and putting weight on the knee. It is more common for the lesions to occur on the medial femoral condyle, because the inside of the knee bears more weight.
The nonoperative treatment is rest and inactivity until the bone heals. But the physical, social, and emotional downside of inactivity for these sports-minded youth can be a problem. Parents, children, and surgeons have asked the same question: is there some way to preserve the bone without prolonged immobility that gets these athletes back on their feet and playing or performing again?
A technique called extraarticular drilling may be possible. Drilling is done using arthroscopy and fluoroscopy. These techniques allow the surgeon to see inside the joint while guiding surgical tools and completing the drilling process. Drilling is done with K-wires that poke holes through the hardened rim of bone that develops around the softened lesion in the bone.
Once the hard shell around the lesion has been breached, new blood supply to the area starts the healing process. The surgeon must be careful not to drill into the knee joint or into areas of healthy knee joint cartilage. That type of drilling approach is referred to as intraarticular technique. Extraarticular drilling avoids the cartilage.
One of the advantages of the extraarticular drilling technique is that motion is not restricted. After the procedure, patients are allowed to stand and walk with crutches. Weight-bearing may be limited on that side for six weeks. Physical therapy to restore motion and stimulate bone healing through the proper exercises and activities can be started. When signs of healing are observed on X-ray, the exercise program is progressed to include light resistance and gradual impact loading.
Swimming and cycling are allowed but running, jumping, and twisting are limited until MRI or CT scan show evidence of good healing. Once the patient is pain free with good leg muscle strength, then the training program can be stepped up to include full return to activities. It still takes some time, but it may speed up the process by months to even a full year.