Accidents are an inevitable part of horse sport, especially where jumping is concerned. Bruce Bladon MRCVS discusses the consequences of a crunching fall
When the screens were drawn around Portersize Just A Jiff on the Olympic cross-country course last year, a worldwide audience held its breath fearing the worst.
“Jiff” had misjudged a corner fence and banked it, falling awkwardly on his side and trapping his rider Camilla Speirs underneath him. As he lay motionless on the floor, course medics decided he should be sedated so his rider could be moved to safety.
“I was in hysterics,” recalls Irish event team member Camilla, who was unharmed. “I was trying not to panic, but I kept thinking, ‘Why isn’t he up?’”
To relief all round, Jiff was later back on his feet and could be transferred to hospital. His chest injuries were to cause further complications, but he lived to fight another day.
A diagnostic dilemma
It has never ceased to amaze me how horses can undergo crashing falls, slamming to the ground in a horrific way, only to get up and walk away. Yet sometimes, as in the case of Jiff, the horse remains down. How to deal with a largely inert horse is a common dilemma for vets working on racecourses or at horse trials.
The commonest cause is that the horse is badly winded (struggling to breathe). This is an occasion when the most important thing you can do as a vet is nothing. Most horses will stand, given time.
Because of the time pressure at competitions to clear the course, guidelines are in place. We usually try to roll the horse over after 10min or so, and always give him 30min before making any critical decisions.
These cases can be surprisingly satisfying to deal with. You arrive and the team puts the screens up. You can’t find anything wrong, despite checking the patient by flexing all his legs firmly, to ensure there is no grating which might suggest a fracture, and then checking the reflexes of the hindlimbs to check for spinal injury. So you stand around looking a little vague. You then decide to roll the horse over, at which point he jumps to his feet and you earn a round of applause from the crowd.
High-impact injuries
Sadly, not every case has such a happy outcome.
When most of us think of fractures, we imagine the high-impact injuries that might occur in a car crash. With horses, however, these are a minority of the cases we deal with.
Most equine fractures are stress fractures, a result of repetitive high loading on the skeleton. It’s like a paperclip — keep bending it and it will suddenly break. It’s not the final snap that’s significant, but all the previous bending.
Fractures such as split cannon bones, knee chips and broken pelvises are usually of this sort. They can, in fact, be a cause of falls. The horrific pile-ups occasionally seen in Flat racing are often the result of one horse developing a stress fracture and falling as a result, bringing others down.
Following a heavy fall we do sometimes see high-impact fractures. Fractures of the accessory carpal bone (the “pisiform” bone sticking out at the back of the knee) are one of the commonest and can result in severe lameness.
Given time, however, the outlook can be excellent. These fractures never actually heal, but they do settle down and don’t cause lameness. Small bone fragments may need to be removed from the knee joint, but in most cases rest is the only necessary treatment.
Fractures of the lateral malleolus, the knobbly bone on the outside of the hock joint, are also commonly seen. Early work back in the 1980s suggested that these horses did not need surgery and would respond to rest, but most vets now recommend removal of the fragments.
This is quite a long and difficult arthroscopic procedure, so there are risks with the surgery. But the long-term outlook for return to full exercise is good if the fragments are removed successfully.
Fatal falls
On occasion, a high-impact fracture can be fatal.
Recovery is rare from the humerus and femur breaks typically seen in National Hunt racehorses. The joint surface is typically broken into multiple fragments, making surgical reconstruction largely impossible.
After a heavy fall, differentiating a horse with a broken spine from one that’s merely winded can be difficult. There may be some palpable (upon touch) abnormalities of the spine and an obvious loss of reflexes in the hindlimbs in the case of a fracture, but signs can be very subtle.
Fractures of the head are quite common. A horse’s head is made largely of air, encased with thin bones. The fall is not always the cause of the damage, however — it’s often the kick in the head from the horse following immediately behind.
This is where horses and humans differ, as equine head fractures almost always have a good prognosis. The loose bone fragments must be removed, but healing is excellent due to a good blood supply and minimal movement of the skin or subcutaneous (underlying) tissues.
Trauma to the calvarium, the part of the skull that encloses the brain, is relatively unusual. Severe brain trauma can occur, however, when a horse rears up and falls over backwards.
The growth plate, where the large muscles of the neck attach to the basisphenoid bone at the base of the skull, is a weak point. When a horse flips over backwards these neck muscles can pull violently and cause a fracture of the basisphenoid bone. Directly above this bone is the optic chiasm where the two optic nerves cross, so this injury can result in sudden and permanent blindness.
Why don’t horses get concussion?
Concussion following a fall is rare. This is partly because it is hard to diagnose — a horse can’t tell you how much his head aches — but there is another reason.
A brain is like a computer. Keeping a computer working properly means keeping it cool, hence its constantly-whirring fan.
Brain cooling is a fundamental and important part of mammalian biology. A human brain is cooled by means of large and complex venous sinuses running underneath the skull. The blood, which has already circulated around the face and cooled, then drains through these venous sinuses over the surface of the brain to reduce its temperature.
Substantial head trauma that damages these sinuses can result in bleeding on to the brain surface. In its simplest form, concussion is a swelling of the sinuses that then press on the brain and cause pain.
So why doesn’t the horse get concussion? The equine “computer” may be a little primitive relative to ours, but it still needs cooling. Horses achieve this with a guttural pouch, a large air pocket at the back of the throat, through which the carotid artery runs, cooling the blood before it reaches the brain.
Thus equine venous sinuses are much smaller than ours and chance of damaging them is less.
Jiff’s classic comeback
Following his accident last August, Jiff was found to have suffered chest injuries caused by landing on a fence flagpole.
“He cracked 2 ribs, which caused a haemorrhage,” explained Camilla, who slept in Jiff’s stable that night as he remained attached to drips and monitors.
Jiff returned to Camilla’s Co Kildare yard within a month, but knock-on effects of the haemorrhage included rotation of a pedal bone. After a lengthy rehab, which included aqua treadmill sessions, the 15.1hh bay gelding was jumping again almost a year to the day after the fall.
“Jiff has brought me from Pony Club to an Olympic games,” said Camilla. “It was a miracle to get him back in action this year, let alone in winning form. We finished seventh at Boekelo in October — pretty amazing for a horse they said I’d be lucky to ride again.”
