Fig. 1. Caudo-cranial projections of the MFC in Group 1 horses. A, Deep sclerosis of the central MFC, (B) MFC sclerosis with an articular lucency, (C) a large MFC concave lucency. Thin arrows indicate sclerosis, thick arrow indicates the lucency.
flattened central articular surfaces with deep scle- rosis. All RAs on the Ca-Cr projection were widest at the joint margin (8–12 mm). At 120 days after set 1, four horses showed improvement, five had worsened, and two were the same. In nine horses radiographed at 240 days after the first set, five horses were improved, three had worsened, and one was the same. The four improved horses had sub- stantial healing of lucencies, and three of the four were unilaterally affected. The three horses that worsened had enlargement or development of lucen- cies (two bilateral, one unilateral), and the same horse had no change in a shallow lucency.
There were 638 horses of an average age of
239 days (range, 124–365 d) in Group 2. There were 287 females (45%) and 351 males (55%). Summaries for Group 2 MFC grades are listed in Table 1. Of the 267 horses with an RA, 106 (39.7%) were affected bilaterally. Of the 162 unilaterally affected horses, 108 (67%) were right MFCs and 54 (33%) were left MFCs. There was no association of horse’s sex with MFC RA. Consider- ing all MFC, there were significantly more abnormal grades in right MFCs (41.8%) than left (24%). There were 188 horses with an average age of 529 days (range, 455–595 d) in Group 3. There
Fig. 2. Caudo-cranial stifle joint projections demonstrating the MFC grades for horses age 1 year. AAEP PROCEEDINGS Vol. 62 2016 409
