Knee – Pigmented villonodular synovitis

CASE HISTORY

49-year-old male evaluate osteoarthritis. Injured 10 years ago while playing soccer.

TECHNICAL FACTORS

Long- and short-axis fat- and water-weighted images were performed. 

KEY IMAGES

This case has no key images.

CASE FINDINGS

• No recent bony macrofracture. 
• A chronic-appearing about 2.5cm flap tear primarily involving outer half of the posterior horn of the medial meniscus. Foci of osteochondral erosion at peripheral medial tibial plateau. Subtle chondral fissuring at medial femoral condyle. 
• Pseudoextruded lateral meniscus with truncated posterior horn. Confluent degenerative change at the anterior horn. No displaced meniscal fragment localized. Confluent chondral fissuring with subchondral erosion at lateral femoral condyle. Stress edema at lateral tibial plateau. Foci of osteochondral erosion at peripheral aspect of lateral tibial plateau. 
• Chronic ACL tear. PCL no acute injury. No acute sprain of the collateral ligaments. Spur at femorotibial compartments. Foci of osteochondral erosion at the posterior nonweightbearing lateral femoral condyle. 
• Patellofemoral alignment within normal limits. No substantive chondral loss at the patellofemoral articulation. Quadriceps and patellar tendons intact. 
• Large joint effusion with hypointense synovial metaplasia and blooming artifact. Multilobulated small gastrocnemius-semimembranosus reflection cyst with synovial metaplasia. A moderate amount of fluid dissecting to the popliteal muscle with synovial metaplasia. 
• Muscles intact.

CASE CONCLUSION

• Severe diffuse pigmented villonodular synovitis of the knee. 
• Chronic ACL tear. 
• Truncated lateral meniscus. Differential includes prior partial lateral meniscectomy and bucket-handle tear. 
• A longitudinal oblique tear at red-red zone of posterior horn of the medial meniscus. 
• Grade 4 chondromalacia at the weightbearing and posterior nonweightbearing lateral femoral condyle.