Knee – Ganglion

CASE HISTORY

Chondromalacia patellae. MMT. Left knee pain.

TECHNICAL FACTORS

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

KEY IMAGES

This case has no key images.

CASE FINDINGS

• Skeletal:
  • No acute fracture osseous contusion or macrofracture. Subchondral osseous edema central aspect of the posterior lateral condyle. Small bone island in the distal femur. 
• Patellofemoral Compartment:
  • Advanced chondromalacia within the apex and medial articular facet. Lateral spurring lateral subluxation; tricompartmental spurring. 
• Retinaculum and Tendons:
  • Lateral retinaculum and MPFL intact. Extensor and flexor mechanism unremarkable. 
• Cruciate and Collateral Ligaments:
  • Intact. No ACL or PCL tear. Note moderate sized cyst in immediate proximity to the ACL origin with regional subchondral osseous edema. Periligamentous cyst as sequelae of mucoid degeneration or ganglion is favored over infiltrative gouty erosion. 
• Menisci:
  • No acute meniscus tear. Notch spurring. Focal erosion weightbearing medial condyle class 3. Scattered class 2-3 chondromalacia of the lateral tibia. 
• Joint Space:
  • No intraarticular body. 
• Femorotibial Compartment:
  • Medial and lateral weightbearing portions of the femorotibial articulation demonstrate nominal cartilage signal heterogeneity without penetrating high-grade chondromalacia. 
• Other Soft Tissue / Popliteal Fossa:
  • Normal signal intensity within surrounding muscles without muscular or soft tissue mass. No distended bursal cyst or evidence of entrapment neuropathy. Semimembranosus bilobed pseudocyst.

CASE CONCLUSION

• Class 4 patellofemoral chondromalacia. 
• Notch spurring and intrasubstance ACL mucoid degeneration or ganglion. Intraarticular gout with erosion of the posterior lateral condyle unlikely. 
• Focal multicentric class 3 chondromalacia medial weightbearing compartment. No acute meniscal tear.