Radiology Case


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Click on the image for magnification

 

Radiographic findings: There is moderate cranial compression of the infrapatellar fat pad and impingement on the caudal fat stripe (arrows). There are small osteophytes on the proximal femoral trochlea, apex of the patella, supracondylar tuberosities, sesamoid bones of the gastrocnemius muscle, and caudal edge of the tibial
articular surface

Radiographic impression: The radiographic findings are consistent with a stifle effusion and a degenerative osteoarthritis most likely secondary to a partial or complete cranial cruciate ligament rupture, other ligamentous injury, or meniscal damage.

Comments: The impingement on the infrapatellar fat pad and caudal fat stripe is caused by increased synovial mass that may be due to effusion, synovial capsular thickening, or both (likely in this case). The periarticular remodeling in this case represents a chronic process in the joint. Palpation of the joint, under sedation, for instability would be recommended in this case. If no instability is detected, an arthrocentesis and/or MRI would be recommended for further evaluation. Knowledge of the anatomy of the stifle joint is important to make an accurate radiographic diagnosis.1 A labeled image of a normal stifle has been included for a radiographic anatomy review.

Key

  1. Femur
  2. Patella
  3. Infrapatellar fat pad
  4. Joint capsule
  5. Tibial tuberosity
  6. Lateral and medial supracondylar tuberosities (muscular attachments of the gastrocnemius muscle)
  7. Medial and lateral sesamoid bones of the gastrocnemius muscle (fabellae)
  8. Femoral condyles
  9. Caudal fat stripe
  10. Intercondylar tubercles
  11. Sesamoid bone of the popliteus muscle
  12. Fibula
  13. Tibia

The images are courtesy of Washington State University, College of Veterinary Medicine, Department of Radiology.

References

  1. Vasseur P. Stifle Joint In: Slatter D, ed. Textbook of small animal surgery. 2nd ed. Philadelphia: W.B. Saunders, 1993;1817-1831.

Dr. John Feleciano, DVM, DACVR
Dr. Renee Leveille, DVM, DACVR

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