The Wilson Test is a knee orthopaedic test commonly associated with osteochondritis dissecans of the medial femoral condyle. A positive result may involve familiar knee pain during extension with tibial internal rotation that reduces when the tibia is externally rotated. The test may support assessment reasoning, but it does not confirm osteochondritis dissecans on its own.

Introduction

Osteochondritis dissecans, often shortened to OCD, is an osteochondral condition involving subchondral bone and the overlying articular cartilage. It most commonly affects the knee, particularly in adolescents and young active people, and may present with vague activity-related pain, swelling, stiffness, catching or locking.  

The Wilson Test is a provocative knee test traditionally associated with OCD lesions of the medial femoral condyle.

It is commonly used alongside:

• knee history and symptom behaviour
• observation for swelling
• Sweep Test or patellar tap
• knee range of motion
• joint-line palpation
• meniscal testing
• functional squat or step-down assessment
• imaging where clinically appropriate

Current clinical resources emphasise that OCD diagnosis and lesion stability are usually assessed using radiographs and MRI rather than a physical test alone.  

Quick Summary

• Test name: Wilson Test
• Also known as: Wilson’s Test, Wilson Sign
• Body region: Knee
• Purpose: Assess pain response associated with possible osteochondritis dissecans of the knee
• Commonly associated presentation: Osteochondritis dissecans of the medial femoral condyle
• Positive finding: Familiar pain during knee extension with tibial internal rotation that reduces when the tibia is externally rotated
• Negative finding: No familiar pain, locking or symptom change during the test movement
• Best used with: History, swelling assessment, knee ROM, functional testing and imaging where appropriate
• Key limitation: Diagnostic accuracy values for the Wilson Test are not well established, and imaging is usually needed to assess OCD lesions

What Is the Wilson Test?

The Wilson Test is a knee special test used to assess symptom response during knee extension with tibial rotation.

The traditional rationale is that internal tibial rotation during knee extension may bring the tibial spine into contact with a classic OCD lesion location on the lateral aspect of the medial femoral condyle. External tibial rotation may reduce this impingement and reduce symptoms.

The test may assess:

• pain during knee extension
• pain change with tibial rotation
• possible mechanical irritation
• symptom reproduction near terminal extension
• side-to-side symptom difference
• catching or locking response

The Wilson Test should not be used as a stand-alone diagnostic test.

Why It Is Used

The Wilson Test may help support assessment reasoning when OCD of the knee is suspected.

It may help professionals:

• assess familiar knee pain during extension
• identify whether tibial rotation changes symptoms
• compare the symptomatic and non-symptomatic knee
• document pain, catching or locking
• guide further assessment selection
• support referral or imaging discussion where appropriate
• monitor symptom irritability over time

The test is most useful when it reproduces the client’s familiar symptoms and when the history is consistent with OCD.

What It Assesses

The Wilson Test assesses symptom response during a specific knee movement pattern.

It may provide information about:

• pain during knee extension
• symptom change with tibial internal rotation
• symptom relief with tibial external rotation
• possible mechanical irritation around the medial femoral condyle
• catching or locking response
• side-to-side difference

It does not directly identify:

• osteochondral lesion size
• lesion stability
• cartilage integrity
• loose body presence
• meniscal injury
• ligament injury
• exact cause of pain
• readiness to return to sport

Who It Is Useful For

This test may be useful for:

• exercise professionals
• rehabilitation practitioners
• strength and conditioning coaches working with allied health teams
• performance coaches
• movement assessment professionals
• students learning knee assessment
• professionals using Measurz or MAT for structured assessment recording

It may be relevant for clients who report:

• activity-related knee pain
• vague deep knee pain
• recurrent knee swelling
• stiffness after activity
• catching or locking
• pain during knee extension
• reduced confidence with running, jumping or sport
• adolescent or young athlete knee symptoms

OCD is often discussed in adolescent or young adult athletic populations, but symptoms and assessment findings should still be interpreted with caution and referred appropriately when suspected.  

When to Use This Test

Use the Wilson Test when the history suggests possible osteochondral involvement and controlled knee movement testing is appropriate.

It may be useful when the client reports:

• vague activity-related knee pain
• deep knee pain
• recurrent effusion
• stiffness
• catching
• locking
• pain near terminal knee extension
• symptoms during running, jumping or stairs
• symptoms that are not clearly explained by simple soft tissue irritation

The test is more meaningful when symptoms are familiar and change with tibial rotation.

When Not to Use or When to Be Cautious

Use caution with:

• acute traumatic knee injury
• large swelling or suspected haemarthrosis
• suspected fracture
• locked knee
• severe pain
• high irritability
• suspected unstable osteochondral fragment
• recent knee surgery
• inability to safely flex or extend the knee
• marked guarding

Stop testing if:

• sharp pain occurs
• the knee catches or locks
• symptoms escalate quickly
• the client feels unsafe
• guarding prevents controlled movement
• the client asks to stop

If the client has a locked knee, sudden swelling, significant trauma, severe night pain, fever, redness, unexplained systemic symptoms or major loss of function, the finding should be escalated for appropriate medical review.

Equipment Required

• Treatment table or chair
• Pain scale
• Symptom location notes
• Measurz recording workflow
• Optional comparison-side notes
• Optional referral or imaging notes where appropriate

Step-by-Step Protocol / Practice

Setup

Position the client sitting with the lower legs hanging over the edge of a table, or lying supine if that version is preferred.

The seated version is commonly described in clinical teaching resources.  

Explain the test before starting.

The client should understand that the test involves controlled knee movement with lower-leg rotation and that it will stop if symptoms become uncomfortable or unsafe.

Client Position

• Client sits on the edge of a table
• Hip is flexed
• Knee begins flexed to approximately 90 degrees
• Lower leg hangs freely
• Thigh remains supported
• Client stays relaxed

Examiner / Professional Position

• Stand or sit beside the tested knee
• Support the lower leg
• Control tibial rotation
• Observe pain response, guarding, catching or locking

Hand Placement

Common hand placement includes:

• one hand stabilising or supporting the knee or distal thigh
• one hand controlling the lower leg, ankle or foot
• optional palpation around the medial femoral condyle or joint region if appropriate

Avoid forceful pressure over painful tissue.

Stabilisation

Monitor for:

• hip rotation
• thigh movement
• quadriceps guarding
• hamstring guarding
• ankle substitution
• facial expression
• withdrawal response

The movement should be controlled and symptom-limited.

Movement or Force Direction

A commonly described Wilson Test sequence is:

• Flex the knee to approximately 90 degrees.
• Internally rotate the tibia.
• Slowly extend the knee.
• Observe whether pain occurs, especially around 30 degrees from full extension.
• If pain occurs, externally rotate the tibia.
• Continue or repeat extension and observe whether symptoms reduce.

A positive response is classically described as pain during extension with tibial internal rotation that is relieved by tibial external rotation.

Instructions

Ask the client to:

• keep the leg relaxed
• report pain, catching or locking
• identify the exact symptom location
• say whether the symptom is familiar
• rate pain from 0–10
• tell you immediately if they want the test stopped

Example instruction:

“I’m going to gently rotate your lower leg and straighten your knee. Tell me if this reproduces your familiar knee pain, catching or locking, and whether the feeling changes when I rotate your leg the other way.”

Positive Finding

A positive Wilson Test may include:

• familiar knee pain during extension with tibial internal rotation
• pain around the medial femoral condyle region
• pain near the final part of knee extension
• catching or locking during the movement
• symptom reduction when the tibia is externally rotated
• clear side-to-side difference

The most meaningful finding is familiar pain that changes with tibial rotation.

Negative Finding

A negative finding involves:

• no familiar pain during the movement
• no catching
• no locking
• no meaningful symptom change with tibial rotation
• no clear side-to-side difference

Stopping Criteria

Stop if:

• sharp pain occurs
• the knee catches or locks
• symptoms escalate quickly
• guarding prevents safe movement
• the client feels unsafe
• the client asks to stop

Safety Notes

• Use slow and controlled movement
• Do not force knee extension
• Do not force tibial rotation
• Avoid repeated provocation in irritable knees
• Record whether external rotation relieved symptoms
• Consider referral or further assessment if OCD is suspected

Positive and Negative Test Interpretation

A positive Wilson Test may increase suspicion of osteochondral involvement, particularly OCD of the medial femoral condyle, when it reproduces familiar pain during extension with tibial internal rotation and symptoms reduce with tibial external rotation.

A positive result is more meaningful when it matches:

• adolescent or young active client history
• activity-related knee pain
• recurrent effusion
• stiffness
• catching or locking
• pain near terminal knee extension
• reduced sport tolerance
• imaging findings where available

A positive result does not confirm OCD on its own.

Other factors may contribute to symptoms during the test, including:

• meniscal irritation
• patellofemoral pain
• synovitis
• cartilage irritation
• ligament-related pain
• bone bruising
• capsular sensitivity
• general knee irritability
• poor relaxation during testing

A negative test may suggest this specific rotational extension movement does not reproduce symptoms.

However, a negative Wilson Test does not exclude OCD or other osteochondral pathology.

Some clients may only report symptoms during:

• running
• jumping
• stairs
• deep squatting
• sport-specific loading
• fatigue
• repeated activity
• mechanical catching episodes

Interpretation is stronger when combined with history, swelling assessment, range of motion, functional testing and imaging where clinically appropriate.

Sensitivity, Specificity and Diagnostic Accuracy

High-quality diagnostic accuracy values for the Wilson Test as a stand-alone test appear limited.

At the time of writing:

• Sensitivity: no high-quality published value found for this exact test and population
• Specificity: no high-quality published value found for this exact test and population
• Positive likelihood ratio: not well established
• Negative likelihood ratio: not well established
• Reference standard: not consistently established for the clinical test

Current OCD guidance places more emphasis on imaging than on any single physical test. Orthobullets summarises that diagnosis may be made radiographically, while MRI is usually required to determine lesion size, stability and cartilage injury.  

A 2022 update on knee OCD similarly states that MRI is indicated in young active people with knee pain and/or effusion to support early diagnosis and treatment planning, particularly by assessing lesion stability.  

Practical interpretation:

• A positive Wilson Test may increase suspicion when it reproduces familiar symptoms.
• A negative Wilson Test does not exclude OCD.
• The test should not be used to determine lesion stability.
• Imaging is usually needed when OCD is suspected.
• The result should be interpreted with history, swelling, mechanical symptoms, age, activity profile and other assessment findings.

Reliability and Validity

Specific reliability values for the Wilson Test appear limited.

Reliability may be influenced by:

• client position
• knee flexion angle
• tibial rotation amount
• movement speed
• symptom irritability
• examiner hand placement
• whether familiar pain is required
• whether symptom relief with external rotation is tested
• client guarding
• comparison-side testing

Validity is stronger when:

• symptoms are familiar
• pain occurs during extension with tibial internal rotation
• symptoms reduce with tibial external rotation
• the client has activity-related knee pain
• swelling or mechanical symptoms are present
• imaging findings support OCD where available

Validity is weaker when:

• pain is vague or unfamiliar
• pain location is unclear
• symptoms do not change with tibial rotation
• the knee is highly irritable
• symptoms are better explained by meniscal, patellofemoral, ligament or inflammatory factors

Because OCD lesion diagnosis and stability assessment rely heavily on imaging, the Wilson Test should be viewed as an assessment reasoning tool rather than a definitive clinical test.  

Common Errors and Limitations

Common errors include:

• forcing knee extension
• forcing tibial rotation
• moving too quickly
• not asking whether pain is familiar
• not checking whether external rotation relieves symptoms
• interpreting any knee pain as positive
• failing to record the angle where pain occurs
• not documenting catching or locking
• not considering meniscal or patellofemoral sources
• using the test as a stand-alone diagnosis

Limitations include:

• limited diagnostic accuracy evidence
• limited published reliability data
• symptom overlap with other knee conditions
• does not identify lesion size or stability
• does not replace radiographs or MRI
• may be negative despite OCD
• may be positive due to other knee pathology
• less useful in very painful, swollen or locked knees

Practical Applications

The Wilson Test may help professionals:

• assess symptom response during knee extension with tibial rotation
• document whether symptoms change with rotation
• compare symptomatic and non-symptomatic knees
• identify whether further osteochondral assessment may be needed
• support referral or imaging discussion where appropriate
• monitor symptom irritability over time

For athletes, it may be used alongside:

• training load review
• jumping and landing history
• running symptom history
• knee swelling assessment
• range of motion testing
• squat or step-down assessment
• return-to-sport confidence measures

For younger clients, recurrent swelling, activity-related pain, catching or locking should be taken seriously and escalated when appropriate.

For Measurz users, the main value is structured recording of symptom reproduction, tibial rotation response, pain angle, mechanical symptoms and related findings.

How to Record This in Measurz

Record:

• test name: Wilson Test
• side tested: left, right or both
• result: positive, negative, unclear or unable to test
• client position: seated or supine
• starting knee angle
• tibial rotation used: internal then external
• angle or range where pain occurred
• whether external rotation reduced symptoms
• pain score from 0–10
• symptom location
• symptom quality
• whether symptoms were familiar
• catching, locking or clicking if present
• guarding or apprehension
• comparison side
• irritability level
• reason for stopping if stopped early
• related findings, such as swelling, ROM, meniscal tests, patellofemoral tests or functional tests
• referral or imaging notes if appropriate
• interpretation notes
• planned retest date if monitoring change

Record whether the main response was:

• familiar pain with internal rotation
• symptom relief with external rotation
• catching
• locking
• pain in another location
• no symptoms
• unclear response
• unable to test safely

This improves:

• repeatability
• communication
• client education
• assessment reasoning
• team consistency
• progress monitoring
• referral communication
• reporting quality

Related Tests / Internal Links

• Sweep Test
• Knee Range of Motion Tests
• Thessaly Test
• McMurray Test
• Steinmann Test
• Patellar Grind Test
• Single-Leg Squat Test
• Step-Down Test

FAQs

What does the Wilson Test assess?

It assesses whether knee extension with tibial internal rotation reproduces familiar pain that may be associated with osteochondritis dissecans of the medial femoral condyle.

What is a positive Wilson Test?

A positive result may include familiar pain during knee extension with tibial internal rotation that reduces when the tibia is externally rotated.

Does a positive Wilson Test confirm osteochondritis dissecans?

No. A positive result may increase suspicion, but OCD is usually assessed using history, examination and imaging. The test does not confirm OCD on its own.

Does a negative Wilson Test exclude OCD?

No. A negative test does not exclude OCD or other osteochondral pathology.

Why does tibial rotation matter in the Wilson Test?

The traditional explanation is that internal tibial rotation may increase contact between the tibial spine and a classic OCD lesion location, while external rotation may reduce this contact.

Are sensitivity and specificity available for the Wilson Test?

High-quality published sensitivity, specificity and likelihood ratio values for the exact Wilson Test appear limited. Imaging is usually needed when OCD is suspected.

What should the Wilson Test be used with?

It is best used with history, swelling assessment, range of motion, mechanical symptom review, functional testing and imaging where clinically appropriate.

Key Takeaways

• The Wilson Test is commonly associated with OCD assessment of the knee.
• A positive finding may involve familiar pain during extension with tibial internal rotation.
• Symptom relief with tibial external rotation strengthens the clinical relevance of the finding.
• The test does not confirm OCD on its own.
• Diagnostic accuracy values for the exact test appear limited.
• Imaging is usually needed to assess OCD lesion size and stability.
• Measurz should record side, position, tibial rotation, pain angle, symptom relief, pain score, mechanical symptoms and related findings.

References

American Academy of Orthopaedic Surgeons. (2022). Osteochondritis dissecans clinical practice guideline. https://www.aaos.org/quality/quality-programs/osteochondritis-dissecans/

Accadbled, F., Vial, J., & Sales de Gauzy, J. (2018). Osteochondritis dissecans of the knee. Orthopaedics & Traumatology: Surgery & Research, 104(1S), S97–S105. https://doi.org/10.1016/j.otsr.2017.02.016

BMJ Best Practice. (2026). Osteochondritis dissecans: Symptoms, diagnosis and treatment. https://bestpractice.bmj.com/topics/en-gb/591

Bruns, J., Werner, M., & Habermann, C. (2018). Osteochondritis dissecans: Etiology, pathology, and imaging with a special focus on the knee joint. Cartilage, 9(4), 346–362. https://doi.org/10.1177/1947603517715736

Masquijo, J., & Kothari, A. (2019). Juvenile osteochondritis dissecans of the knee joint: Current concepts review. EFORT Open Reviews, 4(5), 201–212. https://doi.org/10.1302/2058-5241.4.180079

Mestriner, A. B., Ackermann, J., & Gomoll, A. H. (2022). An update on osteochondritis dissecans of the knee. Orthopedic Reviews, 14(5). https://doi.org/10.52965/001c.38829

StatPearls. (2024). Osteochondritis dissecans of the knee. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK538194/