Osteochondritis of the Knee

Osteochondritis dissecans (OCD) of the knee is a joint condition in which a segment of bone and cartilage separates from the end of the bone. This occurs often due to a lack of blood flow, which can result from overuse of the joint.

The condition manifests as knee dysfunction and pain. The affected bone and its adjacent cartilage can crack and loosen, sometimes detaching completely, leading to premature osteoarthritis and may necessitate surgical intervention. When a piece of bone dies and separates from the rest of the bone, it is called a lesion. Lesions may occur in one or both knees.

Individuals with this condition may present with knee pain as the primary symptom or incidentally discover the condition during x-rays for an unrelated injury.

The exact cause is not known but is believed to be repetitive stress on the knee joint, poor blood flow, and sometimes a genetic predisposition. However, in some cases, it can result from an isolated injury. People with extreme obesity and elevated body mass index are at increased risk. Rapid growth during adolescence may be a contributing factor.

The symptoms of osteochondritis dissecans can vary depending on the severity of the condition and whether the loose fragment stays in place or becomes detached.

Patients generally present with vague, poorly localized knee pain that is aggravated by weight-bearing activity. Stiffness and occasional swelling during or after activity are common as the disease progresses. Locking and catching can indicate advanced disease.

Dr. Waterman will review the patient’s history of knee trauma and inquire about any recent increase in activity levels, previous knee injuries, the duration of symptoms, and family history.

He will perform a thorough orthopedic examination, looking for signs of swelling, deformity, and changes in the knee’s appearance. Dr. Waterman will feel tenderness, assess a range of motion, and perform special tests to identify mechanical symptoms such as joint locking and instability.

X-rays will reveal abnormalities, and an MRI will provide a detailed image of the bone and cartilage. An MRI can help to determine the stage of the disease by the size of the lesion

and the condition of the cartilage. CT scans offer a more detailed view of the bone and can help plan surgical interventions if needed. Occasionally, a special bone scan can assess blood flow, which can help detect osteochondritis early.

In some cases, if the diagnosis remains uncertain after noninvasive imaging, arthroscopy might be performed. This minimally invasive surgical procedure allows direct visualization of the joint surfaces and the affected area. If loose fragments are found during the procedure, it can also serve as a therapeutic intervention.

Treatment options for osteochondritis dissecans depend on the patient’s age, the severity of the condition, and whether the bone fragment is still attached or has become loose. Treatments include:

• Nonsurgical treatment involves cessation of sports and immobilization with a cast, splint, or hinged brace for 4-6 weeks. Pain is treated with non-steroidal anti-inflammatory medications. Physical therapy is initiated after immobilization and when healing is evident on X-rays. Physical therapy is necessary until the patient becomes pain-free and has restored full range of motion. Sports can be gradually resumed when symptoms are gone, physical therapy has been completed, and there is no pain during running, sprinting, or cutting. The entire process takes about 6 months.
• Studies report that 50%-75% of patients will heal with nonsurgical treatment.
• Surgical treatments may be recommended if conservative measures are unsuitable or ineffective after 3-6 months. In adults, surgical intervention is the primary treatment. Surgical treatments include:
  • Minimally invasive arthroscopic surgery to remove loose fragments of bone and cartilage or secure them back to the bone.
  • When the condition appears stable during arthroscopy, the patient may undergo microfracture or marrow stimulation. This involves drilling into the bone to stimulate blood flow, which can lead to the formation of new cartilage. This can be done from behind (retrograde drilling) or through the cartilage (transchondral drilling).
  • When the lesion is unstable or large, it must be repaired.
  • In severe cases, bone grafting may be necessary to replace bone and cartilage. The osteochondral allografts (OCA) may be from a donor or another part of the joint to replace the damaged tissues.

Early diagnosis and appropriate treatment are critical to preventing further joint damage and ensuring the best possible outcome for individuals with osteochondritis dissecans of the knee.