Osteochondral necrosis of the femoral condyles in Thoroughbred foals: eight cases (2008-2018).

The study explores clinical and histopathological traits linked to osteochondral necrosis in the femoral condyles of eight Thoroughbred foals. The findings suggest bacterial colonization as the likely cause, aiding the development of better preventative and therapeutic strategies.

Objective of the Research

In this investigation, the researchers aimed to examine and describe the clinical, imaging, gross, and histopathological abnormalities associated with osteochondral necrosis of the femoral condyles in foals. In particular, the goal was to identify common characteristics that might hint at a shared cause of the condition.

Study Scope and Methodology

• The study involved eight Thoroughbred foals that had been euthanized due to a suspected diagnosis of necrosis of the femoral condyles. Postmortem Computed Tomography (CT) was performed on all distal femoral epiphyseal samples collected from the foals.
• The researchers carefully scrutinized the articular epiphyseal cartilage complex (AECC) of the affected distal femurs, concentrating heavily on the lesions identified in the CT images. These examinations were done grossly and histologically.
• The studied foals were predominantly between 9 and 23 days old, save for one that had reached 85 days of age. Additionally, all but one of the foals had been diagnosed with a concurrent illness, like neonatal maladjustment syndrome or neonatal isoerythrolysis.

Key Findings

• The common radiographic and postmortem CT finding among the foals was a displaced crescent-shaped osteochondral flap from the affected medial femoral condyle. The condition of the synovial fluid from the affected joints was within the normal range or indicated a mild inflammation.
• All lesions displayed osteochondral necrosis along with the detachment of the AECC. Six out of eight foals had polymorphonuclear cells found within their development cartilage canals implying the presence of septic cartilage canals. The researchers interpreted the osteochondral necrosis to be a result of bacterial colonization of the distal femoral AECC, indicating septic cartilage canals.
• This condition was previously thought to be a result of an ischemic event. However, a better understanding of its pathogenesis could result in the formulation of more effective preventative and treatment strategies.