A puncture wound is an injury where the external damage is small, but the wound itself can be deep, sometimes causing damage to important internal structures.
As there is little damage to be seen on the surface, these types of injury can be easily missed. However, if dirt or bacteria has found its way into the wound, this can become a major problem as infection rapidly develops and spreads.
Puncture wounds in horses are particularly worrisome for horse owners as what appears to be a minor issue can turn out to have far more serious consequences and it can be hard to differentiate what is serious and what is not. If in doubt, it is best to seek prompt veterinary attention.
Signs of a puncture wound
Often the first sign that your horse has suffered a puncture wound is a swollen area. This is particularly true of horses’ legs, where the whole leg may swell as the area becomes both inflamed and infected.
In this situation you should look carefully for small wounds in any swollen area. Many are tiny and hard to see. Clues include a trickle of blood or a sensitive spot when you run your hands over the area, which may be combined with localised swelling. If you have a pair of suitable small clippers, carefully clipping the hair away from around the area will make it easier to see what is going on.Once you have located the injury, bear in mind that the damage caused is dependent on the depth of the wound, how dirty it is and whether any vital structures are involved. A puncture wound can be fatal if it reaches key internal structures, such as within the chest, abdomen or the inside of the foot. The most common complication is when a puncture wound results in infection entering a closed cavity such as joint or tendon sheath.
Many first aid manuals warn you to look out for so-called ‘joint fluid’, an oily, clear to yellow substance, and that if you see this discharging from a wound, a joint could be involved. In reality, a wound is often far too messy to spot this, and many benign superficial wounds discharge clear or yellow serum, which can appear similar.
Assess the location of the wound to see if it is near a joint or other critical structure, such as the digital flexor tendon sheath above and below the back of the fetlock. Remember that some joints, such as the elbow, are very large. An injury that seems some distance away from the bending part of the joint may still communicate with it. Equally, infection can spread towards it.
In all cases a vet should be called to assess a puncture wound, or a suspected puncture wound, as it is often more serious that it initially appears and the sooner it receives expert attention, the more likely the horse will be able to make a rapid recovery.
Treatment for puncture wounds in horses
- Clip the coat and carefully clean around a puncture wound ideally using saline or boiled water that has cooled with clean cotton wool.
- Do not spray the wound directly with water, or apply any chemicals such as hydrogen peroxide. This could force contamination deeper, making potential infection worse. It may be useful to hose dirt away from around the wound, but avoid hosing directly onto the wound itself.
- Use a hydrogel on the wound and apply a clean bandage with a dry poultice. This is usually more beneficial than a wet poultice.
- ALWAYS ensure your horse has been vaccinated against tetanus. These wounds provide the ideal environment for the bacteria that cause tetanus to flourish.
Potential causes for concern
- A foreign body could be stuck inside the wound, so ask yourself what could have caused the puncture? Do not try to probe the wound – leave this to your vet
- Consider whether your horse is more lame than one would expect for the size of the wound and let the vet know when you speak to them
Preventing puncture wounds in horses
While puncture wounds of all types can be difficult to prevent, checking your horse over carefully while grooming and after exercise will improve the likelihood of you spotting an injury, enabling you to take prompt action to prevent a more serious problem from developing.
Horses that have been jumping hedges out hunting should be checked very carefully on their return for wounds caused by embedded thorns.
Other simple actions such as making sure your stables and yard are swept frequently, including immediately after a farrier has been working, can reduce the chance of a loose nail or other piece of debris causing an injury.
Frequent checks of paddocks for potentially dangerous items and avoiding riding on high-risk areas such as road margins where unseen debris may be hidden in the grass can also help reduce the risk of injury.
Puncture wounds in the foot
The horse’s foot is at particular risk of puncture wounds, with a penetrating wound caused by a nail or other sharp object being typical. These injuries can be very serious and warrant emergency attention and referral. The severity of the injury will depend on how deep the foreign body has gone into the foot and what structures are damaged. Generally a wound in the middle third of the foot, near the tip of the frog is more likely to be serious.
The recommendation, which can be hard to follow, is that if you find a foreign body within the horse’s foot, leave it in place unless there is a risk of further penetration. This allows the vet to do a radiographic assessment of the direction and depth that the object has travelled.
If the foreign body must be removed, then note where it entered and which direction it went in. Keep the foreign body to show your vet. Note the depth of penetration – and mark on the object if possible.
Apply a clean dry poultice to the foot to keep dirt from entering the puncture.
A review published in the Equine Veterinary Journal in 2013 involved 95 such cases from four UK equine hospitals1. Each had suffered a puncture wound that had penetrating structures inside the hoof capsule such as the navicular bursa, tendon sheath or coffin joint. In many cases more than one structure was damaged — so the nail might have gone through the tendon sheath, the tendon and into the joint.
Each horse was treated intensively with keyhole surgery and every possible technique to prevent infection and restore full function. Despite such efforts, the rate of return to full soundness where the bursa, tendon sheath or joint had been penetrated was only 36%. Only 56% of cases survived and a significant proportion of these were permanently lame.
The time between the discovery of the nail and referral to hospital was shown to affect outcome — emphasising the need for immediate action.