The conformation that is considered ideal is straight legs, defined as:
"Ideally, when viewing the forelegs from the front, a straight line from the point of the shoulder should bisect the entire column of bone all the way to the toe, with equal portions of the bone on either side of the bisecting line."
Both my horses definitely do NOT have straight legs like those above! Their front legs seem to be slightly knock-kneed (also called valgus).
|Gus front leg conformation|
|Molly front leg conformation|
Several pieces of evidence suggest that a slight valgus leg conformation is actually normal, if not beneficial.
1) This website states that a slight valgus conformation is normal.
2) This study based on injuries of racing Thoroughbreds states: "An increase in the carpal angle as viewed from the front (carpal valgus) may serve as a protective mechanism, as the odds for a carpal fracture and carpal effusion decreased with an increase in the carpal angle."
When I pick Gus' legs up and bring them forward and look down the cannon bone from the knee, the legs down from the knees are completely straight. The same is true for Molly's left front. Molly's right front, her problem foot with the side bone, however is different: the cannon bone, and the short pastern are "offset". This can be best seen on the x ray.
See this picture for terminology of bones:
Molly's offset long pastern bone is most likely something that has developed as a foal, due to bad hoofcare and/or injury of some sort. Today, at 8 years of age, this is nothing I can change. Molly's hoof has obviously suffered from this leg conformation, as she developed side bones in this hoof but not in her other front hoof. I am reasonably sure that she had this side bone already as a 3.5 year old, as I remember specifically asking the vet about that bulge that she had in her coronary when I bought Molly. The vet at that time said it was nothing to be concerned about. I guess he is correct, Molly has arranged herself with the situation, she has never been lame, but her FR is a long term liability and I want to do everything in my power to at least provide it with the best balanced trim given her leg conformation. So far, everything looks quite good, the joint spaces are relatively regular and to the degree that this rather bad x-ray can tell, there is no sign of calcifications (arthritis). Not yet! My goal is to keep it this way.