- Clinical science
Osteochondritis dissecans (OCD, OD) is a focal aseptic necrosis of subchondral bone in which a bone-cartilage fragment detaches and becomes displaced in the joint space. School-aged children and adolescents are most commonly affected. OCD occurs as a result of overuse or trauma, and 75% of cases affect the knee. Symptoms include pain and joint locking or catching. X-ray is the best initial test for suspected OCD, but MRI is better able to detect early disease. First-line treatment includes reducing physical activity. Surgery is indicated if the bone-cartilage fragment is completely displaced and includes arthroscopic extraction, open fixation, and transplantation procedures.
- Sex: ♂ > ♀
- Peak incidence: 10–20 years old
Epidemiological data refers to the US, unless otherwise specified.
- The etiology is unknown. Proposed theories include mechanical stress and repetitive trauma.
- Most frequently affected joint: knee (medial condyle of femur)
- In early lesions, nonlocalized pain during physical activity in school-aged children or adolescents
- Gradual stiffness with joint locking or catching
- Antalgic gait with lateral rotation of the ipsilateral foot
- Pain on palpation of the femoral condyles when the knee is in flexion
- Full range of motion is retained
Patients typically retain the full range of motion in the affected joint!
- Initial test
- May be normal in early stages
- More advanced lesions appear as a subchondral bony fragment surrounded by radiolucency.
- Used for early diagnosis in patients with persistent symptoms and normal x-rays and for precise staging
- May show articular cartilage thickening or partial detachment in early stages
Osteochondritis dissecans is a radiographic diagnosis!
Conservative therapy: first-line treatment
- Conservative therapy may be attempted first in patients who do not have detached or displaced intra-articular fragments.
- Children are more likely to improve with conservative management than adults.
- Initially, rest and limited physical activity
- Physical therapy
- Children with completely detached and displaced intra-articular fragments
- Children who have not responded to 4–6 months of conservative therapy
- Most adult patients with OCD, although conservative therapy can be attempted for small or stable lesions
- Arthroscopic extraction of the intra-articular loose fragment
- Other options depend on the stage and size of lesion, as well as skeletal maturity.
- Most patients, especially children without a loose body, heal completely without complications.
- Chronic pain
- Mechanical symptoms
We list the most important complications. The selection is not exhaustive.