Each case of ringbone will be described as either high (pastern joint area) or low (coffin joint area), and by whether it involves the joint (articular) or not (periarticular). Traumatic ringbone may occur anywhere along the pastern. It's important to make the distinction between the types of ringbone because this influences the prognosis for soundness with treatment.
Our table on page 15 lists the various types of ringbone and possible causes. Horses with club feet or upright pasterns are less efficient in distributing forces on impact and this jamming and jarring is hard on the pastern and coffin joints. Biomechanical studies have shown that the hoof wall and these two joints absorb most of the force of impact. Horses whose pastern and foot axis deviates in or out rather than being directly aligned under the fetlock may be at higher risk for ringbone. However, this risk can be minimized by trimming the hoof to keep the bones in their natural alignment.
More ringbone is caused by trimming that forces the foot back under the ankle, or deliberately introduces side-to-side imbalances to "correct" winging in or winging out. "Corrective" trimming can't realign the horse's natural bone axis. When trimming doesn't follow the natural alignment of the bones, uneven forces are developed that can easily result in ringbone caused by joint, joint capsule, tendon or ligament damage.
Put It To Use
- The most common cause of ringbone is improper trimming and balancing of the foot.
When ringbone appears at an early age, the cause is often OCD (osteochondrosis). Defects in the formation of a healthy bone cartilage junction that occur while in the uterus or at a young age lead to joint disease and bone chipping that causes articular ringbone.
Sport: Jumpers, eventers, polo ponies and working Western horses, which must make sharp turns at high speeds, are at increased risk for ringbone both because of uneven joint loading and risk of soft tissue tears (joint capsule, tendons, ligaments).