Ultrasonographic features of the fetlock osteoarthritis in draught horses

Draught fetlock osteoarthritis was diagnosed clinically and radiographically in 20 horses. Ultrasonographic features of the fetlock joint and periarticular soft tissues were evaluated. Enlargement of the joint space, thickening of the joint capsule and digital flexor synovial sheath distention were seen in early osteoarthritis or traumatic synovitis. The SDFT, the DDFT and suspensory ligaments appeared within the normal size and echogenicity. Chronic osteoarthritis and secondary osteoarthritis were diagnosed during fracture healing of the proximal end of the first phalanx. The ultrasound scans showed the joint capsule thickened with presence of hyperechoic masses or hyperechoic dots. The fetlock joint space and the digital flexor tendon sheath had echogenic materials within anechoic synovial fluid. The SDFT and the DDFT were increased in thickness and echogenicity. They appeared adhered, with ill defined borders and marked calcification between the SDFT and the DDFT. Desmopathy of the distal sesamoidean ligaments were observed. In conclusion, fetlock osteoarthritis in draught horses showed ultrasonographic changes in joint capsule and periarticular soft tissue structures. Ultrasonography could be helpful in diagnosis, treatment and prognosis of fetlock osteoarthritis and lameness.