What Ringbone is
Ringbone in horses refers to a painful condition characterized by new bone growth. It affects either the pastern joint (“high ringbone”) or the coffin joint (“low ringbone”).
What causes Ringbone
Bony proliferation accumulating over time on the coffin and/or pastern joints causes ringbone. As with other types of arthritis, signs typically appear when horses reach middle age. Depending on conformation and use, some horses seem to be more predisposed to this condition. Horses with upright pasterns or toed-in conformation suffer from this form of arthritis frequently. Horses that undergo repetitive stress in the pastern region, such as jumpers, barrel horses, or polo ponies, also suffer from ringbone more frequently. Finally, acute trauma in the pastern region can also predispose a horse to developing bony proliferation on the pastern.
Clinical signs of Ringbone
Signs can include a change in gait, such as a short or choppy stride, or overt lameness. Heat, swelling, and/or pain in the pastern joint may also be appreciated.
Diagnosis of Ringbone
A veterinarian may suspect ringbone after palpation of the pastern region and a lameness exam. The lameness exam will likely include flexion tests and regional nerve blocks to localize the source of pain to the pastern. Your veterinarian will take radiographs to identify new bone proliferation around the pastern or coffin joints.
Management/Prognosis of Ringbone
Although it is a progressive and irreversible condition, you can implement a number of management changes to help keep a horse with ringbone more comfortable. Your veterinarian can help you decide what may work best for your horse’s individual needs.
As with any arthritic condition, keeping a horse at a healthy weight is an important part of minimizing stress on painful joints. Your farrier may use various shoeing strategies to limit the forces exerted on a horse’s distal limb joints.
Joint feed supplements such as Cosequin ASU may help some horses. Many horses with joint disease benefit from systemic, injectable prescription joint medications such as Legend, Adequan, or Osphos. Systemic anti-inflammatory medications such as Bute or Equioxx may be a beneficial short term medication for horses during particularly painful times.
Your veterinarian may suggest intra-articular steroid injections. There are several experimental therapies that may eventually be used to target ringbone. IRAP (interleukin-1 receptor antagonist protein), PRP (platelet-rich plasma), and stem cell therapy are on the horizon for treating ringbone. Shockwave therapy has been used to treat ringbone as well.
In many cases of high ringbone, the bony proliferation may eventually cause the pastern joint to fuse. When that happens, the absence of motion dramatically reduces arthritic pain. Veterinarians sometimes elect to speed up this process. Arthrodesis (surgical fusion of the joint) and facilitated ankylosis (injection of alcohol into the joint) are two methods of achieving joint fusion.
By Lauren Alderman, DVM, CVA