Osteochondritis dissecans (OCD) of the knee is a focal disruption of the subchondral bone with overlying cartilage that most often affects adolescents and young adults. The condition progresses from a stable bone defect under intact cartilage to, in some cases, separation of the bone and cartilage fragment into the joint. Early recognition preserves treatment options and outcomes.
What Is Knee OCD?
OCD is a condition in which a segment of subchondral bone loses its blood supply, softens, and can separate from the surrounding bone. The overlying cartilage, nourished by joint fluid, may remain intact or may detach with the bone fragment.
In the knee, OCD most commonly affects the medial femoral condyle (approximately 70 percent of cases), followed by the lateral femoral condyle, the patella, and, less often, the trochlea.
OCD lesions are staged by stability:
- Stage I: subchondral bone injury with intact articular cartilage
- Stage II: stable fragment with partial separation, cartilage intact
- Stage III: unstable fragment in situ, partial detachment
- Stage IV: displaced fragment (loose body), crater in the joint surface
Stage at presentation determines treatment. Early recognition and protection of stable lesions in young patients allow healing. Delayed diagnosis converts healable stable lesions into displaced fragments requiring more invasive treatment.
Causes and Risk Factors
- Adolescent age (10 to 17 years old is the highest-risk group)
- Repetitive sports involving running, jumping, and cutting
- Possible genetic predisposition, with bilateral cases in some patients
- Prior knee injury in some cases, though many OCD lesions occur without trauma
- Skeletal immaturity, which affects healing potential (juvenile OCD has better prognosis than adult OCD)
Symptoms
- Vague knee pain with activity, initially low-grade
- Swelling with activity
- Catching, clicking, or locking if a fragment becomes unstable
- Stiffness after rest
- In displaced lesions, a mechanical block to motion from a loose body
Diagnosis
Dr. Chudik’s evaluation includes the age, activity pattern, and symptom duration. Physical examination looks for effusion, tenderness, and mechanical signs. Wilson’s test (pain with internal rotation during extension) can reproduce symptoms in medial femoral condyle lesions. X-rays identify classic OCD lesions, with specific views (notch view) improving sensitivity. MRI is the imaging study of choice for staging lesion stability, cartilage status, and any associated subchondral edema. Skeletal age assessment with X-rays of the opposite knee or hand helps stratify juvenile versus adult OCD. The Westmont office has on-site high-field MRI and X-ray.
Treatment
Non-surgical treatment is the first line for stable lesions in skeletally immature patients. It involves:
- Activity modification or rest from impact sports
- Bracing in selected cases
- A targeted physical therapy program once symptoms allow
- Serial imaging to monitor healing, typically every three to six months
Most juvenile stable lesions heal with six to 12 months of appropriate rest and follow-up.
Surgical treatment is indicated for unstable or displaced lesions and for stable lesions that fail to heal with non-surgical treatment. Dr. Chudik performs arthroscopic procedures including:
- Drilling of stable lesions to stimulate revascularization and healing
- Fixation of in-situ unstable fragments with bioabsorbable implants or metal fixation
- Osteochondral autograft transfer (OATS) for displaced lesions with small to medium defects
- Osteochondral allograft transplantation for larger defects in older patients
- Removal of loose bodies when the fragment is not salvageable
Recovery and Outcomes
Recovery with non-surgical treatment ranges from six to 12 months with gradual return to sport after imaging confirms healing. Recovery after arthroscopic fixation or grafting involves protected weight-bearing for four to six weeks, progressive motion and strengthening, and return to sport at four to nine months depending on procedure.
Outcomes in juvenile OCD are good when the lesion is stable and treatment is initiated early. Adult OCD and displaced lesions have less predictable outcomes, particularly for long-term cartilage health.
When to See Dr. Chudik
Schedule an evaluation if an adolescent or young adult has persistent knee pain, swelling, or catching that does not resolve with rest, or if prior imaging has identified an OCD lesion. Call 630-324-0402 or request an appointment online.