My wife just went up country for a riding clinic. Her horse landed off a jump & she went one way and the horse went the other. She broke her arm (radius) with the bone coming out of place and overlapping her wrist. The pain was excruciating. At Vernon hospital they anesthetized her, putt traction on her arm and neatly put the bone back in place. This process is called “reducing” the fracture. A cast was put on to maintain everything in place. Stabilization resulted in immediate pain control. She said “now I know how those poor horses feel” & that gave me the idea for this article.

Let’s talk about fractures. “All fractures” is too big a topic so more specifically let’s discuss pastern fractures, common to both Standardbred & Thoroughbred race horses as well as working show horses.

First: some basic anatomy. The typical pastern fracture involves the long pastern bone (P1 or 1st Phalanx) which is the foundation of the fetlock joint (commonly called the ankle by many horsemen) and extending to just above the hoof. The short pastern bone is below it and together they comprise the pastern joint (proximal interphalangeal joint).

How do these fractures occur? They all start at the fetlock joint. The cannon bone (mc3 or mt3) above has a marked ridge which runs front to back. This sagittal ridge fits into the corresponding groove in the top of the pastern. It is because of this central ridge that the fetlock can only swing forward and backward. The joint cannot move sideways or the fetlock joint is dislocated. More importantly torque forces and concussion can drive the sagittal ridge into this groove and start splitting the bone into two pieces.

What do you see when a horse has a fracture? This depends on the extent of the break & how stoic the horse is. Many of these show little or no swelling! The tip off for me is the history of extreme pain at some stage during work. In other words the horse does not want to bear weight when it first occurs. Some of these are severe right off the bat but many are very small micro fractures and don’t extend very far at all. Mild fractures respond temporarily to bute and stall rest. Some of these horses can be sound walking and continue to train. The fracture can then open up further and the cannon bone splits the pastern into pieces.

How do we diagnose these fractures? The history of being fracture lame at some time and multiple front to back radiographic (x-ray) projections. If suspicious I always x-ray before blocking since blocking can cause full weight bearing resulting in aggravation of the fracture.

What is the treatment? In extremely mild cases the fracture only involves the groove. These can be treated with stall rest only. I usually recommend 2 months absolute stall rest followed by further radiographs and 1 month on a walker before resumption of training.

Mild cases where the fracture is visible progressing downward but stopping short of the cortex can be treated with stall rest and a cast. My preference is to surgically put 1 or 2 screws into the bone for 3 reasons. The most important issue is the integrity of the joint surface. If that is split apart the horse will develop arthritis in the fetlock and either not perform or have a much shorter racing lifespan. By compressing the bone at the joint we ensure that the cannon bone does not keep splitting the pastern and provide support. The second reason for surgery is that it shortens the healing time because it decreases the gap size. The third reason for surgery is that a cast is unnecessary in these mild cases and pressure sores do not become an issue. The downside of surgery is anesthesia, surgical complications such as infection and cost. Modern anesthetic regimes with intense monitoring, training & personal experience of the surgeon & clinic ensure that your dollar is well spent. Direct surgical monitoring with fluoroscopy & technology such as self tapping screws placed through small incisions makes this a minimally invasive surgery with a good to excellent prognosis. With mild to even moderate non displaced fractures we have had great success with horses continuing to race without arthritis. If the fracture extends into the pastern joint the prognosis is not as good since many horses develop secondary arthritis in the pastern joint.

First aid: Any time a horse is suspect of a fracture below the knee or hock we recommend immobilization until x-rays are taken. This can be as simple as putting him on crossties in the barn or may require a splint or splint boot if coming off the track or shipping to the clinic. We have a splint that we lend out for this purpose. Stabilization of the fracture is important to stop trauma to the blood supply & maintain reduction. Otherwise by the time some of these horses reach the clinic the bone can be separated into multiple pieces.

Disaster fractures: the sad story of “Barbaro” involves a severely comminuted (bag of marbles) pastern fracture. The jockey, Edgar Pravo, did an amazing job by pulling up and restraining the horse prior to the horse being stabilized. A great example of first aid – minimize movement of a fracture!

The difficulty with a shattered bone is that if a major strut is not available for support the weight of the horse and the force of the cannon bone downward is overwhelming resulting in screws bending or tearing out of the bone and collapse of the fixation. As opposed to minor fractures which can be screwed using a minimally invasive technique (small incisions) these bones are displaced & have to be repositioned requiring opening the skin completely. This increases the chance for infection. Founder or laminitis is another complication. The horse is made to bear weight evenly on all 4 legs. If non weight bearing on one limb for any length of time the others have to take the additional weight. The horse’s shock organ –the laminae, the hoof wall-coffin bone junction, gives way. The result is that the bone in the foot (coffin bone) rotates or sinks through the sole – usually a fatal complication.

Take home message: Luckily most of these are not disaster situations. Horses can get back to racing through prudent initial management, x-rays and appropriate treatment.