What are the commonest injuries in racehorses?
Thoroughbred racehorses can be considered elite equine athletes but, unfortunately, like their human counterparts, they are vulnerable to a variety of common injury heights. Granted that thoroughbreds stand up to 17 hands, or 5’8″, weigh in at up to 550kg, or 0.6 Imperial tons amd, depending on health and age, gallop at speeds of 30mph or more, on average, it should come as no surprise that large, repeated loads applied to their limbs can result in bone or soft tissue injury. The job of the thoroughbred racehorse trainer, therefore, is to provide opportunities for horses to increase their cardiovascular fitness, strength and load-bearing capacity, through high-speed exercise, without working them beyond the limits of their endurance.
Bone injuries in racehorses range from obvious, traumatic long bone fractures, which may occur on the racecourse, to less obvious, but nonetheless serious, musculoskeletal injuries. One of the most common types of the former is a so-called condylar fracture or, in other words, a fracture of the cannon bone above the fetlock, or ‘ankle’, of a horse. For the uninitiated, the cannon bone is a long, tubular bone in the lower leg, which is subject to large loads during high-speed exercise and, therefore, vulnerable to repetitive strain injury.
Like any long bone fracture, a condylar fracture can, occasionally, be difficult to treat successfully. Indeed, in the most severe cases, a surgical, locking compression plate, complete with screws to stabilise the bone may be required. Even so, the injury may not be life-threatening and, generally speaking, the prognosis for a return to racing is a good one.
Elsewhere, another common site of musculoskeletal injury is the joint between the hind leg and the spine, known as the sacroiliac joint. The sacroiliac joint functions to transfer propulsion from the hind legs to the spine and, as such, is a major point of load transfer between the hind leg and the vertebral column when during the stance phase of the stride or, in other words, when the hoof is in contact with the ground. Sacroiliac pain may be caused by inflammation of the joint itself or the ligaments surrounding and may manifest itself as a loss of hind leg propulsion, as the result of a shortened stride length, or a ‘bunny hopping’ gait of the hind legs
Common soft tissue injuries in thoroughbred racehorses include injuries to tendons, which attach muscle to bone, and ligaments, which attach bone to bone. Both types of fibrous connective tissue are widespread in the body of a horse.
As far as tendons are concerned, the most commonly injured is one of the major tendons in the lower leg, known as the superficial digital flexor tendon (SDFT). Indeed, the classic injury known as a ‘bowed tendon’ is the result of curvature along the length of SDFT. Injuries to the SDFT and, less commmonly, to the deep digital flexor tendon (DDFT), which runs down the back of the leg, are serious insofar as they effect the integrity of limb support. Full recovery from tendon injuries is possible, granted careful treatment and lengthy rehabilitation, but such injuries do commonly reoccur.
The most commonly injured ligaments, on the other hand, are the suspensory ligaments, which, in the foreleg, attaches the back of the knee to the fetlock joint and, in the hind leg, attaches the back of the hock, again, to the fetlock joint. Both ligaments are vulnerable to injury, which can occur anywhere along their length, during exercise. Ligament injuries vary greatly in severity and it is that severity which determines the level of treatment required.