Necrosis of the femoral condyles in a four-week-old foal: clinical, imaging and histopathological features.

This study presents a case of a 4-week-old Thoroughbred filly foal suffering from necrosis of the femoral condyles, the cause of which was suggested to be ischaemic in nature. This case was observed with symptoms of lameness, joint abnormalities, and extensive separation of the articular-epiphyseal cartilage complex in the subchondral bone, leading to recommendation of euthanasia.

Overview of the Study

In this research, the authors examined a peculiar case involving a young Thoroughbred filly foal. The foal presented with symptoms of lameness in the right hindlimb and a history of sepsis, which led researchers to conduct further clinical evaluations and imaging examinations.

Clinical Observations and Imaging Results

• The foal was found to have swelling in both the femoropatellar and femorotibial joints, evident of effusion.
• Upon ultrasonography and radiography of the right stifle, signs of joint collapse and periarticular swelling were observed, further indicating damage and inflammation.
• Computed tomography exhibited abnormalities in bone density, specifically in the medial femoral condyle of the right hindlimb and the lateral femoral condyle of the left hindlimb. This abnormality is suggestive of possible bone decay or necrosis, but does not explicitly confirm it.

Diagnosis and Euthanasia

• Due to the severity of the observed lesions, the researchers considered the condition of the foal to be critical. The severity of the disease, along with likely poor quality of life as a result, led the team to recommend euthanasia.
• Upon post-mortem examination, gross examination and microscopy revealed extensive separation of the articular-epiphyseal complex from the subchondral bone of the condyles in the femur. Such separation is indicative of extensive damage and necrosis of the bone.

Conclusion: Ischaemic Aetiology

• The condition of the foal’s bones and the femoral condyles in particular, as assessed through histology, suggested an ischaemic origin for the disease — that is, the skeletal damage was likely caused by inadequate blood supply to the bone.
• Similarities were drawn between the observed condition of the foal’s femoral condyles and cases of osteochondrosis and avascular necrosis of bone. The similarities may hint at common pathological mechanisms or common influences in the progression of these diseases.