Osteochondritis Dissecans – Knee

Lower Limb

Overview

Osteochondritis dissecans (OCD) is a condition where a segment of articular cartilage and underlying bone becomes separated from the femoral condyle, typically affecting the medial femoral condyle of the knee. This condition occurs most commonly in adolescents and young adults and can progress from stable lesions to loose bodies within the joint. Early diagnosis and appropriate management are critical to prevent premature osteoarthritis and preserve knee function.

Pathophysiology

OCD develops through repetitive microtrauma and impaired blood supply to the subchondral bone, leading to localized necrosis of bone beneath the articular cartilage. The medial femoral condyle is most vulnerable due to its tenuous blood supply and the compression forces it experiences during weight-bearing and knee flexion activities. Progressive separation occurs when mechanical forces exceed the healing capacity, potentially resulting in a loose osteochondral fragment within the joint.

Patient Education

Early detection and activity modification are crucial to prevent progression; maintaining appropriate strength and flexibility through guided exercise can help stabilize the knee and reduce symptoms while healing occurs.

Typical Presentation

Site

Medial femoral condyle (70% of cases), lateral femoral condyle, or patellofemoral joint; symptoms localized to anteromedial or anterolateral knee

Quality

Poorly localized, dull ache or sharp pain with mechanical symptoms; catching or locking sensations if fragment is loose

Intensity

Variable (2-7/10) depending on stability of lesion; may be minimal at rest but increases with activity

Aggravating

Weight-bearing activities, running, jumping, squatting, pivoting movements, prolonged standing, downhill walking, knee flexion under load

Relieving

Rest, ice application, activity limitation, knee extension, non-weight-bearing positions

Associated

Effusion, quadriceps atrophy, reduced knee range of motion, hamstring tightness, mechanical symptoms (catching/locking) if loose body present, Wilson's sign (pain with knee flexion and internal tibial rotation), functional instability

Orthopaedic Tests

Test descriptions are written with AI assistance from standard clinical texts. Where a test lists Sources, its description has been checked against them; those sources are independent and do not endorse OsteoKit. Accuracy figures and grades (A–D) appear only when checked against the published study; tests without one are marked “No accuracy study”.

Further reading: full test procedures are described in standard clinical examination texts, e.g. Magee & Manske, Orthopedic Physical Assessment (7th ed.), and Cook & Hegedus, Orthopedic Physical Examination Tests: An Evidence-Based Approach (2nd ed.).

Grade A
A+ABCDStrong clinical value: substantially changes the diagnosis (LR ≥10 or ≤0.1)
useful both to rule in and rule out.

Lachman Test

Procedure

Patient supine, knee bent to 20–30°. Stabilise the lower femur with one hand and pull the upper tibia forwards with the other, comparing the amount of movement and the end-feel with the other knee.

Positive Finding

More forward movement than on the other side, with a soft or absent end-point.

Sensitivity / Specificity

85%/94%

Reference: Benjaminse A et al., J Orthop Sports Phys Ther 2006; PMID 16715828

Interpretation

Tests the anterior cruciate ligament, not osteochondritis dissecans. It is included to check for a coexisting ligament injury when a young athlete presents with knee pain and swelling. Note: the Lachman test assesses anterior cruciate ligament integrity; its figures derive from ACL-rupture populations (Benjaminse 2006) and it appears here only to screen for a concomitant ACL injury, not osteochondritis dissecans itself.

Sources

Grade B
A+ABCDGood clinical value: meaningfully changes the diagnosis in one direction (LR 5–10 or 0.1–0.2)
best for ruling IN (confirmation).

Thessaly Test (at 20° and 5° flexion)

Procedure

Patient stands on the affected leg, holding your hands for balance, knee bent to 5°. Ask the patient to rotate the body and knee in and out three times. Repeat with the knee bent to 20°. Test the good knee first.

Positive Finding

Joint line pain, locking or catching during rotation.

Sensitivity / Specificity

75%/87%

Reference: Smith BE et al., Evid Based Med 2015; PMID 25724195

Interpretation

A meniscal test. In osteochondritis dissecans, catching or locking can come from an unstable fragment or loose body, which needs orthopaedic referral. Thessaly test at 20° for meniscal tears: pooled sensitivity 75%, specificity 87% (Smith 2015). Low evidence quality; a meniscal test rather than one specific to osteochondritis dissecans.

Sources

Grade C
A+ABCDModest value: a small but usable shift in probability (LR 2–5 or 0.2–0.5)
modest, supportive value.

Joint Line Tenderness Test

Procedure

Patient supine, knee bent to 90°. Palpate along the medial and lateral joint lines from front to back, and compare with the other knee.

Positive Finding

Focal tenderness at the joint line that reproduces the familiar pain.

Sensitivity / Specificity

83%/83%

Reference: Smith BE et al., Evid Based Med 2015; PMID 25724195

Interpretation

Used mainly for meniscal tears. In osteochondritis dissecans, tenderness is often over the femoral condyle itself (felt with the knee bent) rather than the joint line. Joint line tenderness for meniscal tears: pooled sensitivity 83%, specificity 83% (Smith 2015 meta-analysis). In osteochondritis dissecans this is a non-specific finding.

Sources

Grade C
A+ABCDModest value: a small but usable shift in probability (LR 2–5 or 0.2–0.5)
modest, supportive value.

McMurray Test

Procedure

Patient supine. Fully bend the knee, then rotate the tibia out and straighten the knee while pressing on the inner side (medial meniscus); repeat with the tibia rotated in and pressure on the outer side (lateral meniscus). Keep a hand on the joint line.

Positive Finding

A painful click or clunk felt at the joint line, reproducing the familiar symptoms.

Sensitivity / Specificity

61%/84%

Reference: Smith BE et al., Evid Based Med 2015; PMID 25724195

Interpretation

A meniscal test. In osteochondritis dissecans, a click or catch may come from an unstable fragment rather than the meniscus. Mechanical symptoms need imaging and orthopaedic referral. McMurray test for meniscal tears: pooled sensitivity 61%, specificity 84% (Smith 2015 meta-analysis). Low evidence quality.

Sources

No accuracy study

Wilson Test

Procedure

Patient seated, knee bent to 90°. Internally rotate the tibia and slowly straighten the knee. If pain appears (usually around 30° of flexion), externally rotate the tibia and see whether it eases.

Positive Finding

Pain at the front and inside of the knee during extension with internal rotation, relieved by external rotation.

Interpretation

Designed for osteochondritis dissecans of the lateral part of the medial femoral condyle. It is often negative even when a lesion is present, so a negative test does not exclude it. In a young person with activity-related knee pain, effusion or locking, arrange X-rays including a tunnel view. No validated diagnostic-accuracy source supports the figures previously shown; the Wilson test is widely reported to have low sensitivity for osteochondritis dissecans.

Sources

No accuracy study

Effusion Bulge Sign (Ballottement Test)

Procedure

Patient supine, knee straight and relaxed. Stroke upwards along the inner side of the knee to empty that area, then stroke down the outer side and watch the inner side. For larger effusions, squeeze the suprapatellar pouch down and press the kneecap onto the femur (patellar tap).

Positive Finding

A bulge of fluid returning on the inner side (bulge sign), or the kneecap tapping onto the femur (patellar tap).

Interpretation

Shows fluid in the joint. In a young person with activity-related knee pain, a recurrent effusion is a reason to image for osteochondritis dissecans or other internal damage. The previously cited source did not support the figures shown; no validated sensitivity/specificity is established for the bulge/ballottement sign.

Sources

⚠ Red Flags

  • •Acute traumatic onset with immediate severe pain and hemarthrosis
  • •Progressive neurological symptoms including lower limb weakness or sensory changes
  • •Signs of infection: fever, severe warmth, redness, or systemic symptoms
  • •Acute locking with inability to extend knee (loose body causing mechanical block)
  • •Signs of compartment syndrome: severe swelling, pain out of proportion, pain with passive stretch
  • •Vascular compromise: absent distal pulses, severe cold limb, color changes

⚡ Yellow Flags

  • •Young athlete with excessive training load and perfectionist traits
  • •Significant fear-avoidance behavior limiting appropriate activity progression
  • •Low mood or depression secondary to activity restriction and functional loss
  • •Pressure from parents or coaches to return to sport prematurely
  • •Psychosocial stressors coinciding with symptom onset or exacerbation
  • •Overtraining syndrome or sports-related identity issues

Osteopathic Techniques

Refer first

Treatment depends on age, lesion stage and location. Juvenile lesions without a displaced fragment are treated by stopping sport and immobilising the knee for 4–6 weeks, then physiotherapy once healing shows on X-ray. Refer for orthopaedic assessment and imaging.

Rehabilitation Exercises

Supine Knee Flexion and Extension

Range of MotionBeginner

Supine Hamstring Stretch with Strap

StretchingBeginner

Quadriceps Stretch Prone or Standing

StretchingBeginner

Supine Quadriceps Sets with Isometric Hold

StrengtheningBeginner

Side-Lying Hip Abduction

StrengtheningBeginner

Prone Hip Extension

StrengtheningBeginner

Seated Knee Extension with Isometric Hold

StrengtheningIntermediate

Supine Bridge with Hip Activation

StrengtheningIntermediate

Single-Leg Stance on Stable Surface

BalanceIntermediate

Quadruped Rocking for Hip Mobility

PosturalIntermediate

Single-Leg Stance on Unstable Surface (Foam Pad or Balance Disc)

BalanceAdvanced

Single-Leg Mini Squat with Upper Limb Support

StrengtheningAdvanced

Referral Criteria

  • •Loose osteochondral fragment visible on imaging causing mechanical symptoms unresponsive to conservative care
  • •Progressive lesion enlargement or development of further separation on sequential imaging
  • •Failure to improve after 3-6 months of appropriate conservative management
  • •Recurrent effusion or swelling despite rest and activity modification
  • •Acute traumatic event with hemarthrosis or severe mechanical symptoms requiring urgent assessment
  • •Age consideration: skeletally immature patients with large lesions may require surgical evaluation to prevent progression
  • •Functional limitations affecting activities of daily living despite conservative treatment
  • •Concern regarding undiagnosed loose body or advanced cartilage degradation requiring MRI clarification