Wilson Test: How to Detect Osteochondritis Dissecans of the Femoral Condyle

Osteochondritis dissecans is one of those conditions worth keeping on your radar when working with adolescents and young athletes who present with knee pain without a clear traumatic mechanism. The Wilson Test is a specific, lesser-known maneuver, but very useful for pointing suspicion toward the medial femoral condyle, the most common location for this injury.

What Does This Test Measure?

The Wilson Test aims to reproduce pain through a position that increases contact between the tibial spine and the affected area of the medial femoral condyle during active knee extension with internal tibial rotation. If pain appears at a specific angle and disappears when the tibia is rotated externally, that's a fairly characteristic sign.

Equipment Needed

• Treatment table
• No additional tools needed

How to Perform the Test

1. The patient lies supine or sits on the edge of the table, with the knee flexed to 90°
2. Ask them to internally rotate the tibia and hold that position
3. Next, ask them to actively extend the knee slowly, while maintaining internal tibial rotation
4. Watch for pain around 30° of flexion (approximately)
5. If pain appears, ask the patient to externally rotate the tibia without changing the flexion angle: if the pain clearly disappears or decreases, the test is considered positive

Common Mistakes

• Not maintaining internal tibial rotation throughout the active extension
• Not checking for "relief" with external rotation, which is the part that gives the test its specificity
• Confusing pain from other causes (patellofemoral, meniscal) with this test's specific pattern

How to Interpret the Results

Result	Interpretation
Pain around 30° of active extension with internal rotation that improves with external rotation	Positive — suggests osteochondritis dissecans of the medial femoral condyle
Pain present that doesn't change with external rotation	Inconclusive — likely another cause of pain (patellofemoral, meniscal)
No pain throughout the range of motion	Negative

The Wilson Test is a clinical screening tool, particularly relevant in adolescents with persistent knee pain and no clear trauma. A positive result, combined with context (age, exertional pain, possible intermittent swelling), justifies referral for medical assessment with imaging (X-ray/MRI).

Related Tests

When assessing knee pain in young athletes, it's also worth checking:

• Clarke's test (patellar grind test) — to rule out a patellofemoral component as the cause of pain
• McMurray test — to rule out associated meniscal involvement

Why Tracking Matters in Young Populations

Osteochondritis dissecans in growing adolescents can progress very differently depending on the case, so periodic monitoring of pain and function is important. In Movalytics you can record the Wilson Test result alongside the progression of pain and sports activity for the young athlete, keeping a clear history to share with a pediatrician or orthopedist if needed.

Frequently Asked Questions

At what ages is osteochondritis dissecans most common? It's most common in growing children and adolescents, especially those who play sports involving intense jumping, running, or changes of direction. Does a negative Wilson Test rule out osteochondritis dissecans? Not definitively. It's a screening test with limitations, so for persistent knee pain in young people without a clear cause, imaging is usually recommended regardless of the test result. What happens if the test is positive? The usual course is referral for imaging (X-ray, and MRI if needed) and adjusting sports load while the diagnosis is confirmed, avoiding impact activities that worsen the pain.