Torn muscles aren't as common in horses as less severe strains or pulls, but those minor strains are often difficult for the layperson to diagnose. Unfortunately, your horse is more likely to tear that strained muscle without adequate rest and recovery, so what once was minor now becomes much more serious. It's critical you contact your veterinarian if you suspect any type of lameness, or a sudden unwillingness to perform physically.
Depending on location and severity, your horse will need anywhere from six to eight weeks, to as much as one year, to recover from a torn muscle. This doesn't mean he'll be solely cooped up in a stall the entire time, however; physical therapy, such as hand walking, is important to your horse's recovery, so follow your veterinarian's instructions carefully.
Your horse is more likely to tear that strained muscle without adequate rest and recovery, so what once was minor now becomes much more serious.
Some of your horse's muscles take more of a pounding than others. His risk of being injured is greater if he performs in a demanding sport, such as eventing or racing, but even a high level of playful pasture activity can do damage, especially if the ground is slippery. Your horse's risk of a muscle tear increases if he is out of shape, so you are doing him -- and yourself -- a favor by keeping him fit.
Jumping, speed, quick turns, uneven or slick footing, repetitive stress on limbs and horse fatigue are all risk factors for equine muscle tears.
Ligaments and Tendons
Jumpers, racehorses and eventers put a lot of stress on their legs, increasing the likelihood of injuring their suspensory ligaments. These ligaments run just below the knee in the front legs and the hocks in the rear legs.
A mild injury consisting of a few torn collagen fibers must be detected early or the ligament can rupture -- this can even result in a bone fracture as it tears away from the bone. Contact your vet if you notice any inflammation, heat or negative reaction to touch; she can perform an exam and do an ultrasound to pinpoint the location of the injury.
A mild strain will typically heal in six to eight weeks, but odds are that you're looking at approximately one year for full recovery from a suspensory ligament tear or rupture.
Overweight horses are also more susceptible to ligament tears, so part of keeping your horse fit is to curb obesity.
The deep digital flexor tendon runs from the back of the leg to the bottom of the coffin bone inside the hoof. This tendon bears stress when a horse lands after a jump, for example, or when he pushes off to gallop. But it can also be stressed if the horse has low heels or long toes as a result of his natural conformation, or improper shoeing.
A horse with a natural conformation defect such as this needs to be shod to reduce stressing this tendon as much as possible. If your horse injures this tendon where it attaches in his foot, it can be difficult to diagnose, or be mistaken for a foot injury. Your vet can perform an ultrasound if the injury is higher up, but typically you will need to find a clinic capable of magnetic resonance imaging -- MRI -- to detect it in the hoof. As with the suspensory ligament, your horse should recover from a mild strain of this tendon in six to eight weeks. A tear will typically lay him up for eight months or more.
Some horses get tendonitis, or chronic inflammation of their deep digital flexor tendons. Regular anti-inflammatory injections may allow them to continue their performance requires at the same or lower levels.
Treatment is similar for both suspensory ligament and deep digital flexor tendon strains and tears.
- cold therapy with ice wraps or cold hosing immediately after injury or diagnosis;
- a course of anti-inflammatory medication such as phenylbutazone for pain and inflammation;
- stall rest, typically with leg wraps;
- a short course of hand-walking to encourage healing, beginning with just a few minutes a day and then gradually increasing;
- a gradual return to exercise that takes place over several months, with periodic ultrasounds and exams to monitor and adjust.
Your vet may also recommend extracorporeal shock wave treatment or regenerative therapies such as stem cell therapy or platelet-rich plasma. Some of these treatments can accelerate healing, but don't expect a radical reduction in lay-up time. They may, however, strengthen the healed tissue. Treatment research and therapies can change quickly, so discuss with your vet the costs and advantages of treatment options and whether it's worth traveling to another clinic for any not offered in your area.
If your vet recommends wrapping the injured leg, be sure to wrap both legs, particularly for front-leg injuries. This reduces the pressure on the healthy, weight-bearing leg.