PVNS Diagnosis

Nov 07, 2011: MRI - Lower Extremity Joint w/o contrast
History: Mild Left Knee pain, lateral swelling

Findings: 
Ligaments: The ACL, PCL, MCL and colateral ligamentous complex are intact.

Menisci: There  is globular degenerative-type horizontal pattern tear body lateral meniscus with extension to the free edge. The medial meniscus is intact. The posterior meniscal roots are preserved.

Osseous Structures and Articular Surfaces: There is no acute fracture. No focal bone marrow contusions are identified. There are changes of grade 2 medial compartment chondromalacia along the posterior inner and peripheral medial femoral condylar and opposing medial tibial plateau articular surfaces. There are changes of grade 2 lateral compartment chondromalacia along the central to posterior and peripheral lateral femoral condylar and opposing lateral tibial plateau articular surfaces. There are changes of grade 2 chondromalacia patella along the medial patellar facet and adjacent patellar medial eminence, as well as along the medial femoral trochlear articular surface and adjacent femoral trochlear groove.

Extensor Mechanism: The extensor mechanism is intact. The medial and lateral patelar reticula are within normal limits.

Miscellaneous: There is small knee joint effusion. There is a small to moderate-sized complex Baker's cyst. There is diffuse internal joint space synovitis with hypointense signal throughout the synovium, suggesting hemosiderin deposition. This appearance is compatible with underlying PVNS. There is a 5 cm x 3 cm complex cyst along the posterolateral joint line, which may reflect ganglion, synovial cyst or atypical parameniscal cyst. The popliteal neurovascular structures are maintained. There is no evidence of muscular atrophy, nor signal alteration to suggest denervation-type injury. No high-grade musculotendinous injury is seen.

Impression:
1. Intact ligaments.
2. Globular degenerative-type horizontal pattern tear body lateral meniscus with extension to free edge.
3. Intact medial meniscus.
4. Grade 2 medial compartment chondromalacia, lateral compartment compartment and chondromalacia patella.
5. Small knee joint effusion and small to moderate-sized complex Baker's cyst. There is diffuse internal   joint space synovitis with hypointense signal throughout the synovium, suggesting hemosiderin deposition. The appearance is compatible with underlying PVNS. There is a 5 cm x 3 cm complex cyst along the posterolateral compartment joint line, which may reflect a ganglion synovial or atypicl parameniscal cyst.

Index and Glossary of terms: 
What is Pigmented Villonodular Synovitis: 
Knee Anatomy Movie:


Grade Chondromalacia:  
Grade 0: healthy cartilage 
Grade 1: the cartilage has some soft spots 
Grade 2: minor cartilage tears are visible 
Grade 3: deep lesions in the cartilage that are more than 50% of the cartilage layer 
Grade 4: the cartilage tear goes all the way to the bone