Fig. 3. Sequential caudo-cranial projections of the MFC in a young Thoroughbred that developed a large rounded lucency.
degree of return to the normal trabecular bone pattern. Substantial healing occurred in some horses in this study (Fig. 4); however, a return to normal did not occur. Bone remodeling is driven by the local mechan-
ics.18,19 Frequency and amplitude of external load are contributing factors, but loading rate seems to be the primary stimulation for osteo- cytes20 that act as strain gauges within mineral-
ized tissue.21 Osteocytes recruit osteoblasts,21 which increase intramembranous bone formation on existing trabeculae, resulting in thickened trabeculae and radiographic sclerosis. However, when loading parameters exceed the failure threshold (occurring at very small strains in trabecular bone22) microcracks form.23 Diffuse microcracks are produced during constituent ac- tivities24,25 and are managed by a balance of the
Fig. 4. Examples of healing of medial femoral condylar abnormalities on caudo-cranial projections taken 6 months. Letters indicate the same horse.
