Equine - Timely Topics

Leg Wounds 101

Dr. Nathan Canada, Equine Surgery Resident

2013-08-29 19.06.48.jpgIf you have owned a horse for any period of time, you know that horses and wounds go hand in hand. It truly is a question of when and not if. When your horse develops a wound, there are many salves, treatments, bandages, and opinions available which can be confusing and even contradictory. Living in the digital age, we turn to the vast amount of information available to us via a computer. As with everything else that you can read on the internet, just because it is there doesn’t mean it is true. The validity of the information we turn to is important because false information can be detrimental to our horses. Wound healing in horses is a complicated process where lack of understanding leads to the vast amount of misinformation available to owners. However if you follow a few simple rules, treating a wound can be relatively straightforward.

“Wound” is a general term that can encompass a wide range of injuries including minor abrasions to degloving injuries where the horse’s skin is peeled away from the body. More important than outward appearance of the injury is the anatomical location. A small inconspicuous puncture wound or laceration over a synovial structure (i.e. joint or tendon sheath) can be far more detrimental to your horse’s health than the most ghastly wound on the hip or shoulder. With that being said, getting your vet involved sooner rather than later is in your horse’s best interest. Early intervention can save you time and money, but more importantly it can save your horse’s life.

Initial wound therapy involves cleaning debris from the wound with a cold hose and using dilute betadine solution to help disinfect the tissues. A compression bandage should be placed to stop any bleeding and keep the wound clean until your veterinarian can assess your horse. This is a very important step because the longer the wound stays dirty, the greater the risk of infection. Once infected, the success rate of suturing a wound closed and having it stay together is decreased. A handout demonstrating how to apply a compression bandage can be found on the VHC equine webpage. If you do not have the materials available to place a compression bandage, you can apply a tight polo wrap after placing 2 quilted or pillow wraps around the leg. The same rules apply to the horse that walks up to the barn with an old wound; clean it, bandage it, and call the vet.

With early intervention, the hope is to suture the wound closed thereby decreasing the time needed for the wound to heal along with reducing any blemishes that might occur. In some instances wounds cannot be closed, and the horse is sent home to be managed while the wound heals. Being horse owners, we have an innate drive to “do something” for the wound. This usually entails driving down to the feed store and buying the latest and greatest salve that claims to kill bacteria, stop proud flesh (a bright, pink, cobblestone appearance), and save the world all for $9.99. Contrary to the claims associated with these products, they can and frequently do, hinder wound healing rather than help it.

Daily wound cleansing with dilute betadine solution (mix with water or sterile saline until it resembles a strong brewed tea) followed by cold hosing for ten to fifteen minutes will help reduce any debris or infection present in the wound bed. If you cannot overcome the urge to place a salve on the wound, stick with triple antibiotic, silver sulfadiazine, or a chlorhexadine cream for the first three to five days in a fresh wound. After this period, no creams or medications should be placed in the wound because they will stop new cells from bridging the gap between the wound edges. Products marketed to reduce proud flesh should be avoided because they will kill any new cells that come into the wound thus stalling the wound healing process.

Keeping the wound bandaged is a crucial part of wound therapy, but too much of a good thing can actually cause problems. Wounds need to be bandaged to keep the exposed tissue clean and protected from the environment while the granulation tissue fills the wound gap. However if the bandage is kept on for a prolonged period of time, it can promote the production of exuberant granulation tissue (proud flesh). So this begs the question, how long should one leave a wound bandaged? A bandage should be changed every 24 hours to assess how the wound is healing, and once the wound is completely covered by a layer of granulation tissue, bandaging can be discontinued. This seems counter intuitive because the wound has not completely healed, but the granulation tissue is a natural barrier to bacteria and debris that keeps everything underneath this layer healthy and clean. If left alone, a scab will form over the granulation tissue and the skin will move across the granulation bed at a rate of 1 millimeter a day. This means our job as an owner is to sit and wait, which is the most difficult step. If we tamper with the wound by taking off the scab, placing topical medication on the wound, or keeping the leg wrapped, we are deterring the normal wound healing process and can create problems like proud flesh.

Despite our best efforts proud flesh can rear its ugly head and frustrate everyone involved with managing your horse’s wound. Simply defined, proud flesh is granulation tissue that rises above the margin of the skin thus keeping the skin from moving across the wound bed. Wounds that occur in areas of high motion (i.e. the legs) are more prone to developing proud flesh. This occurs because every time the leg moves, the granulation tissue develops microscopic cracks. The body responds to these cracks by filling them in with more granulation tissue, and with time, this produces proud flesh. So how do you combat proud flesh? Again, resist the urge to go out and buy any product that guarantees to reduce proud flesh. These products will reduce the proud flesh, but they also will destroy any new skin that has formed over the wound causing any progress that was made to be lost. Since the wound is no closer to being healed, more proud flesh will be produced creating a vicious cycle that prevents wound healing. The best treatment for proud flesh is frequent debridement (tissue removal) by your veterinarian. Unlike any chemical you put on the wound, your veterinarian can differentiate what tissues need to be removed and what needs to stay. Therefore, the new skin formed will be kept and the proud flesh will be removed to allow for continued closure. It might take a few trips to the vet, but it will save you time, money, and lots of frustration.

No two wounds you encounter will be the same and determining how bad the wound is can be quite difficult. The outward appearance of the wound or the amount of blood being lost can make owners frantic, so it is important to have a simple game plan in place. When your horse gets a wound remember the four Cs: stay Calm, Clean the wound, Compression bandage, and Call the vet. Following these simple steps will ensure your horse has the best prognosis possible and save you from the frustration of dealing with non-healing wound.