Published in modified form in EQUUS magazine.
Guardrail. A horse to believe in on a pitch black night eerie with the screeching of wilderness beasts, when the snow is 20 inches deep and the trail less than two feet wide skirting
switchbacks along a 200 foot drop-off. Mike Kelley and a friend had ridden up the Williams Creek drainage to set up a third season elk camp, climbing more than 3000 feet from trailhead to
the Divide and over. They’d planned a day ride, just bringing lunch, but the deepening snow had slowed them down. It took courage and trust to negotiate the trail back home in the dark.
Mike and Guardrail were a team.
Guardrail was only two when Mike and Karen bought him in Missouri, a handsome gray Missouri Fox trotter gelding. Mike used him to train his field trial dogs for several years and then for
trail riding and packing. Guardrail would haul a pack, an elk, or a neophyte rider to the high mountain vistas.
Karen claimed the sure footed horse when he was five. His gaits were very smooth and “he remained an energetic horse with a great desire to please … He’s never lost his footing in ten years
on the trail,” wrote Mike. This is the kind of horse who could save your life on a switchback, on a narrow trail with steep drop-offs, over downed timber in the way.
Guardrail was twelve when Mike brought him to our clinic at the end of summer riding, concerned about his change in gait. My husband and partner, Dr. Jim Latham, examined the compliant gray
who was lame on his right front leg at the walk. There was a firm swelling at the pastern joint. Guardrail was not sensitive to hoof testers but he was very sore to lower limb flexion. The
lameness blocked to 90% sound with an abaxial sesamoid nerve block using lidocaine. We set up the x-ray and took some films.
The x-rays showed irregular bony proliferation on the dorsal surface of distal P1 and dorso-lateral aspects of proximal P2—with osteoarthritic bone spurs encroaching on the proximal
interphalangeal (pastern) joint. There were areas of periosteal proliferation medial and lateral on distal P-1 at the site of origin of the collateral ligaments of the joint.
Guardrail had high ringbone.
Treatment options were discussed; correcting the trimming to bring the overgrown toes and heels back to allow easier breakover and slightly open the front of the pastern joints. Jim
discussed using Bute and considered pastern joint injections, and discussed the possibility of shock wave therapy at a referral practice.
Ringbone is associated with the job description of the horse—western performance competitors, polo ponies and jumpers are more likely to develop the disease--but acute injury, catching a
foot in a hole or in the rocks or rapping the joint on a trailer can lead to degenerative joint disease. Subchondral bone cysts or osteochondrosis, a delayed calcification of bone, or
angular limb deformity in foals can also lead to ringbone. Guardrail may have injured his right front pastern on a steep mountain trail, or running in his pasture. He had never complained.
In late fall, Mike took Guardrail to Southwest Equine Medical and Surgical Center in Scottsdale, Arizona. Jeff Alldredge, DVM, MS, DACVS, operated on Guardrail, arthrodesing (surgically
fusing to prevent movement) his right front proximal interphalangeal (pastern) joint using 3 parallel 5.5mm cortical bone screws lagged across the joint after the cartilage of the joint was
removed with a curette. Guardrail was in a cast for a couple of weeks, then in a splint. He was home in a week and doing well one month post op. He’ll be confined to his stall and a small
paddock with slow controlled exercise for several more months. Horses tend to be sound by about 8-9 months post op. Most horses are out of competition, or use, for about a year.
The cost of pastern arthrodesis ranges from $4500 to $5500 including surgery, casting and up to two weeks of hospitalization.
The overall prognosis for surgical arthrodesis of the proximal interphalangeal joint has been reported to be over 70% for sound use of the limb, slightly higher in the rear legs. In the
foreleg, the arthrodesis may change the biomechanics of the coffin joint and navicular apparatus and a small percentage of these horses may develop heel pain down the road. It is important
to rule out any preexisting coffin joint or navicular syndrome problems before surgery.
Alternate techniques have included lag screws alone or in combination with a dynamic compression plate, and casting post operatively. The more securely the joint
is held immobile, the more comfortable the horse. With successful surgery, good postop controlled exercise, and time, Guardrail returned to the mountains.
After 3 years, Guardrail again developed a lameness in his right front foot. X-rays showed the presence of arthritic spurs in the distal phalangeal (coffin) joint.
Fusion of that joint is not as successful and not often recommended. But in the fall of 2009, Mike and Karen wanted to take Guardrail to the mountains one more time
and more than anything, they wanted him to be comfortable. Jim injected the coffin joint with triamcinolone, a steroid shown to be cartilage sparing and anti-inflammatory
in horses. Mike and Karen reported that Guardrail was significantly more comfortable in just a few days. We discussed a low dose Bute regimen before and after exercise.
We will reevaluate Guardrail this summer.
Many horses are good trail horses, but when your life is at stake, a horse like Guardrail is priceless.
