II. Epidemiology
- Knee is most common site for Osteochondritis Dissecans
- Incidence: 30 to 60 per 100,000
- Bilateral knee involvement in 30 to 40%
- Males affected 3 times more often than females
- Peak Incidence
- Children under age 12 years
- Young adults
- Often missed at time of injury when it occurs
- Found later on Knee XRay
III. Pathophysiology
- Avascular subchondral bone necrosis
- Articular fragments may also separate
IV. Types: Sites involved
- Medial femoral condyle (80 to 85%)
- Lateral aspect most often affected
- Lateral femoral condyle (10 to 15%)
- Patella (5%)
V. Symptoms
- Poorly localized aching Knee Pain and swelling
-
Knee Locking, catching or giving-way Sensation
- Occurs if loose body present
- Morning stiffness
- Knee Effusion may be recurrent
-
Knee Pain provocative factors
- Strenuous activity
- Twisting knee motion (tibia internal rotation)
VI. Signs
- Full knee range of motion
- Quadriceps atrophy on affected side
- Decreased thigh circumference
- Tenderness at affected femoral condyle with knee flexed
- Wilson Test
VII. Imaging
VIII. Management: Conservative (esp. if Growth Plates open)
- Relative rest initially for 1-2 weeks
- Knee Immobilization
- Minimal weight bearing
- Modify activity level for 6 to 12 weeks
- Criteria for return to full activity
- No subjective pain
- Normal physical exam
- XRay shows signs of heeling
- Isometric quadriceps Exercises
- Anticipate healing over time
- Surgical arthrotomy or arthroscopic surgery
- Indicated if Fracture fragments > 1 cm diameter
- Lateral femoral condyle