Q. I have two differently-bred Miniature Horses, one yearling and one weanling, and both have a horrible clunking sound that definitely comes from their hocks. I only hear it when they walk, never at the trot or canter.

Some people have told me it is their growth plates and they will grow out of it, but I am not completely satisfied with that answer and have been trying to find someone that has experienced this same problem who can give me some better reason. Can you explain what this condition is and if it can be treated?

Tina, Australia

A. Both of the horses that you describe are young, and this is probably why the growth plates were suggested as being a potential cause. However, this is not likely to be the source of the noise. With the fact that this noise is identified when the horse walks, I would suspect that they are suffering from intermittent upward fixation of the patella. This condition is often associated with an audible snap whenever the patella releases from the medial trochlear ridge of the femur, and it usually occurs when the horse moves from rest or standing, rather than when the horse is already in motion. The hind leg is in stiff extension with the fetlock flexed, and once it "pops," the leg is freed up and can flex normally again