What is an overreach injury?
An overreach injury occurs when a horse steps on the back of a fore limb heel with the toe of a hind limb. In extreme cases an overreach injury can be potentially life threatening for a horse. This is because there are several extremely important structures on the back of the leg.
What factors increase the risk of an overreach injury?
Overreach injuries are more common in horses with short backs and/or active hind legs! They are also more common in muddy conditions, when the horse's front foot may stay on the ground for a second longer than it normally would, allowing the hind foot to come into contact with the heel bulbs before the front leg has been lifted. The horse must also be well trimmed and shod; too long a toe on the hind feet can increase the risk of the horse over reaching.
What are the most common areas affected?
The horse more often will cut into his heel bulbs when he over reaches, which, although rarely life threatening, may well mean a few weeks, or more, off work, whilst the wound heels, and this could indeed end your competition season early.
How to tell?
An overreach injury can vary in appearance; it could present as small cuts and abrasions, heat and swelling with no wound, or as deep lacerations and open wounds.
How to treat an overreach?
A heel bulb wound is very difficult to keep clean, due to its proximity to the ground. It is also very tricky to bandage this area, as any bandages will just end up like a bracelet around the pastern. Some heel bulb injuries can be so severe as to require the horse to have a foot cast applied, to allow the wound to heel without movement. For minor cuts and abrasions it is advisable to keep the horse in as clean an area as possible leaving the wound to heal, cleaning it once or twice a day depending on the severity. Always consult your veterinarian if you are unsure how deep the wound is or at any signs of infection.
What’s the most sensitive area?
The most serious would be if the horse struck into the back of his pastern. A few millimetres under the skin, on the back of the pastern, lies the lower portion of the tendon sheath. This tendon sheath is a synovial structure, which means it as important as a joint as far as infection goes.
Higher up - overreach injuries on the back of the leg may also end up with the horse in surgery, due to lacerating tendons on the back of the leg, or once again going into the tendon sheath just above the fetlock.
How serious is this?
If a horse overreaches and cuts into the back of his pastern, he may well end up on the operating table. If the injury penetrates the tendon sheath, then it will require surgical flushing and closure.
How do you prevent overreach injuries?
Overreach injuries can be prevented by correctly fitting over reach boots. If overreach boots are too big they may end up being trodden on by the hind feet, resulting in a nasty fall. Keeping hind toes short will also reduce the risk of injury.
Natalie McGoldrick - MRCVS