Osteochondritis dissecans (OCD) is a joint condition that primarily affects children, teenagers, and young adults. It occurs when blood supply to a specific section of bone end is cut off, causing that area to soften and eventually die. As the bone weakens, it can separate from the surrounding healthy bone, taking a piece of cartilage with it. This leaves a lesion or “pothole” in the joint surface.

While it can affect elbows, ankles, shoulders, and hips, OCD is most commonly found in the knee, specifically on the inner edge of the thigh bone (medial femoral condyle). The loose fragment may stay in place, or it can detach completely and float inside the joint space, causing instability.

Symptoms

Symptoms often develop slowly over months or years. Early on, pain might only appear during intense activity. However, if the bone fragment loosens or detaches, symptoms become more pronounced and can include:

• Locking or Catching: A distinct clicking sound or a sensation that the joint is stuck.
• Swelling and Stiffness: Reduced range of motion after exercise.
• Instability: A feeling that the knee or joint is “giving way.”

Sporadic OCD is often caused by repetitive stress – small, unnoticed injuries from high-impact activities like running or jumping that accumulate over time. A rarer form, Familial OCD, is genetic and linked to a mutation in the ACAN gene, which affects cartilage strength.

Diagnosis and Treatment Options

Diagnosis typically involves X-rays or MRIs to visualize the bone and cartilage. Treatment depends on the severity of the lesion.

• Conservative Care: Since young bones heal well, many cases in children resolve with rest, bracing, or crutches to remove pressure from the joint. Physical therapy is crucial to restore strength.
• Surgical Intervention: If conservative methods fail or the fragment detaches, surgery may be required. Surgeons can drill into the bone to stimulate new blood flow, pin the loose fragment back in place, or use bone grafts to repair the damaged area.

Early diagnosis is key to preventing long-term complications like early-onset arthritis. If your child complains of persistent joint pain or locking, it’s worth a closer look.