Osteochondritis

Osteochondritis is a term used to describe disorders that involve the bone beneath a joint’s cartilage and, in many cases, the cartilage itself. The conditions range from inflammatory or ischemic changes in the subchondral bone to fractures of the cartilage-cap region. The most widely recognized form is osteochondritis dissecans (OCD), in which a segment of subchondral bone and its overlying cartilage becomes weakened and may separate from the surrounding bone.

Etiology and risk factors: The exact cause is not always known. It is thought to reflect a combination of mechanical stress, repetitive microtrauma, and localized vascular insufficiency during growth. It most often affects children and adolescents, particularly during rapid growth, and is more common in those who participate in high-load sports. OCD can occur in several joints, most commonly the knee, followed by the elbow and ankle.

Symptoms and examination: Patients typically present with joint pain that worsens with activity, swelling, and sometimes mechanical symptoms such as catching or locking if a fragment is loose. Range of motion may be limited, and joint tenderness may be present.

Diagnosis: Evaluation includes history and physical examination, followed by imaging. X-rays can show changes in the subchondral bone; MRI provides detail about cartilage, stability of the lesion, and surrounding tissue.

Treatment: Stable, smaller OCD lesions may be managed nonoperatively with activity modification, bracing, and physical therapy. Unstable, progressive, or displaced lesions, or those not improving with conservative care, may require surgery, such as drilling to promote revascularization, fixation of the fragment, or cartilage restoration techniques like osteochondral grafting.

Prognosis: With appropriate treatment, many patients regain function, though large or unstable lesions carry a risk of persistent pain or early osteoarthritis.