You are considering buying an otherwise perfect horse. But the X-rays come back and the vet has noticed a bone chip. Do you pass on the Horse?
Bone chips or chip fractures of horses' joints are properly termed osteochondral fragments. Osteo (bone) and chondrol (cartilage) describe the makeup of the fragments that can cause irritation and lameness in a horse's joints. In horses, the major component of the fragment is normally bone.
While chip fractures can occur in any breed and discipline, they seem to be most prevalent in racing Thoroughbreds, perhaps because of the high-speed work they do. Chip fractures can occur in all joints, but are most likely to be in the fetlock and knee joints. Chips can be the result of poor conformation, as with a horse that is back at the knee. The rate at which a young horse is developed on the training track or in the arena can also contribute to chips. Too rapid a progression with training when joint bones are not yet able to keep up with the damage can play a role in the development of bone chips.
Larry Bramlage, DVM, MS, Dipl. ACVS, a board-certified surgeon at Rood & Riddle Equine Hospital in Lexington, KY has lectured that if the chip fracture or fractures happen when a horse is still growing or during a period of rest, the joint will try to isolate the fragment. It does this by surrounding it with scar tissue in an effort to render it smooth and nonirritating, in the sort of way an oyster makes a pearl from a grain of sand. The size of the chip is not of particular significance, but the amount of debris the chip sheds is highly significant. The debris serves to irritate the joint and, if the shedding continues, can cause ongoing inflammation, resulting in arthritis. On the other hand, if the debris shedding ceases, there is a strong possibility the joint will heal.
Not all bone chips are created equal. Some cause little or no hindrance to the horse's well-being or ability to perform. However, if the chip causes serious problems, a veterinarian can remove the chip through arthroscopic surgery and, if the damage is not too severe, the joint can return to normal.
If you suspect your horse has a bone chip or if you are considering buying a horse with a history of a bone chip, be sure to talk to your veterinarian to determine the soundness of the horse and possible treatment options.