Thinning of articular cartilage in the domestic fowl

Thinning of articular cartilage was identified in pelvic limb joints of broiler and Leghorn-type fowls. Almost all of 100 fowls examined showed cartilage thinning or loss in hip and knee joints. Particular attention was paid to proximal femora; in these, the principal mechanism of cartilage loss involved processes described as "peripheral remodelling". From the edge of cartilage sheets, fibrovascular tissue removed articular cartilage by two mechanisms. Either a pannus of fibrovascular tissue covered the articular surface or non-osseous tissue invaded through discontinuities in the bone plate. As in man, peripheral remodelling appears to be age-related and unrelated to regressive or destructive cartilage loss.