Page 111 - January 2019

Ringbone is the term for osteoarthritis of the pastern or coffin joint and most commonly occurs in the front limbs.
90% of horses that undergo surgery to fuse
a hind pastern go back to athletic function. Horses with surgery in the front limbs do well, but have a lower chance for full athletic function due to more weight-bearing and biomechanics of the front leg though there will be improvements in lameness,” he says.
Some horses do better than others. “Some horses that we think would do great, don’t respond as well as we’d hoped, and others that we had less hope for surprise us. At our hospital, pastern joints are the most common type of bone plating procedure that we do.”
There are some other techniques for fus- ing this joint, including chemical methods. “Injections are sometimes given to try to stimulate fusion. At this point in time they are not really a good alternative to surgical fusion. However in severe cases, these injec- tions can provide relief,” he says.
Nutritional supplements that promote joint health may have some benefit, espe- cially when trying to prevent these types of injuries. “Omega-3’s, Glucosamine, MSM, ASU and hyaluronic acid may help to a cer- tain degree, though once the joint is dam- aged or arthritis has set in, these cases are much more difficult to manage with nutra- ceuticals or medications alone,” Herthel says. The most common medications used to reduce the pain and inflammation associated with ringbone are the non-steroidal anti- inflammatory drugs, such as phenylbutazone (Bute) or firocoxib (Equioxx).”
The pastern joint can be difficult to man- age medically, so surgical fusion is often the best choice. “If we can get the pastern to fuse, we can hopefully get these horses back to comfort and athletic use. It is a long process and we generally give them six months to a year off from work for optimum chance for healing. It’s a significant surgery. The lower limb stays in a cast for two to three weeks, and then is protected with heavy bandaging for a bit longer. We’ve had remarkable success with this procedure,” says Herthel.
LOW RINGBONE
“Surgical fusion for high ringbone is very successful, whereas fusion for low ring-
bone is rarely done and is purely a salvage procedure. When there is osteoarthritis in
the coffin joint, it can be very problematic because of this joint’s higher range of motion. Corticosteroid and hyaluronic acid joint injec- tions can help alleviate some of the pain and inflammation, though they are purely pallia- tive. Newer products may be more beneficial for health and longevity of the joint,” he says.
“Regenerative therapies such as PRP (platelet rich plasma), stem cells, and autolo- gous conditioned serum (ACS), which is the
lack of motion in the joint. “There may be a mechanical lameness, but the horse is not uncomfortable, and the coffin joint may overcompensate for lack of motion in the pastern joint. The stride may be changed, though the horse is no longer experiencing discomfort,” Herthel says. Often the horse is quite comfortable, but simply doesn’t have enough movement in that joint for a completely normal stride. Thus, the stride may be shorter.
TREATMENT
If the horse is suffering pain and lame- ness from arthritis in the pastern joint, it can be treated medically or surgically. The pastern joint itself is a low-motion joint, but it can move about 20 degrees. “This makes it challenging to treat,” says Herthel. “It is low motion, but it takes a substantial load carrying the weight of the horse at each stride. When trying to manage ringbone, we may not have the best outcome for long term soundness with just medical inter- vention. It’s an unforgiving joint. Once it suffers trauma or cartilage damage, it keeps degenerating. Other joints can be managed with neutraceuticals or intra-articular injec- tions, but the pastern joint does not seem to respond as well.
“Currently, the method of choice regarding treatment of ringbone that fails to respond to medical intervention is to surgically fuse the joint by using several techniques. The most common is to use a bone plate and screw combination using a locking plate system.” After the surgical site heals and there is no more instability and inflammation, these horses are generally significantly improved.
“The majority of these horses do quite well. We’ve found that horses with issues in the hind limbs tend to do better. More of them experience a full recovery, since those joints bear less weight than the front legs. The ultimate goal for these horses is to get back to athletic performance. About 80 to
A common treatment of ringbone is to surgically fuse the joint with a bone plate and screw combination using a locking plate system.
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EQUINE HEALTH