The hock is the most powerful functioning joint in the horse’s body. Healing a wound in this area, therefore, can be complicated. The main points to remember are to first evaluate the wound, secondly stick to the Three-Stage Bandaging Protocol and finally, maintain a regular exercise program for the horse so that adhesions can be broken down and granulation tissue shaped appropriately.
EVALUATING THE WOUND Despite our best eff orts, accidents do hap-
pen, and when a horse injures his hocks, the fi rst thing to do is evaluate the level of injury: 1st
Level: Broken skin and minor tendon/
tendon sheath damage. As shown in the diagram, the hock is an intricate network of tendons, tendon sheaths and ligaments. If the skin is broken, it is likely that some of the underlying mechanics have been disrupted. Fortunately, this level of injury can be healed using the platelet-rich plasma (PRP) treat- ment without much complication. 2nd
Level: Exposed bone. If there is ex-
posed bone, you should keep in mind that there is definitely tendon damage. If the surface of the bone (periosteum) has been damaged, it is likely that avascular necrotic bone will result, and this can complicate heal- ing. Granulation tissue will grow directly off a healthy bone surface but not off avascular necrotic bone. Photo 1 shows a typical healing pat ern
for a wound with underlying avascular ne- crotic bone. Ideally, the sliver of dead bone will slough and granulation tissue will grow from the healthy bone beneath it (Photo 2). Sometimes, however, the granulation bed
will grow over the dead bone from the sides and in this case surgery is required to remove the embedded piece. Avascular necrotic bone becomes the equivalent of a big splinter or any foreign body that the horse’s system will try to reject. T e wound will not heal if there are trapped foreign bodies in the granulation tissue. 3rd
Level: Joint damage. If the joint capsule
has been compromised; there is an extreme risk of infection. T is is a veterinary crisis and should be treated immediately by a pro- fessional.
HEALING HOCK WOUNDS WITH PRP
T e fi rst article in this series (see August Trail Blazer, p. 16) included an in-depth de-
WWW.TRAILBLAZERMAGAZINE.US • November 2011 | 39
scription of our platelet-rich plasma (PRP) treatment protocol. Here is a brief review of that process with regards to hock wounds: Peppy, an AQHA team-roping horse,
caught his leg in a guy wire loop of a power pole. His injury involved two major wound sites—one inside at and above hock level with exposed bone and tendon, and the other below the hock on the outside that had exposed bone and a lacerated long digital extensor tendon. Stage 1: Aſt er thoroughly decontaminat-
ing the wound with non-cytotoxic wound wash, use occlusive bandages that trap the PRP gel and body fl uids at the wound site. Change every 3-4 days, decontaminating the wound with non-cytotoxic wound wash before applying the fresh PRP gel. T is process is repeated until the granulation bed reaches skin level (Photo 3). Stage 2: T is is the most critical stage for
preventing granulation overgrowth. Hocks are extremely susceptible to overgrowth due to the constant motion over the joint, so extra care must be taken to initiate stage two at the appropriate time, when granulation tissue has reached skin level. Use a wet-to-dry bandage with NO gel. T is stage is about maturing
the granulation bed, not growing more, so we want the bandaging to allow air to dry the serum on the surface of the granulation tissue. We’re fi ghting moisture. Our experience
has shown that moisture is a huge culprit in causing granulation overgrowth (Robert Jones bandaging tends to keep the wound too moist). Use a light wrap over 4x4 gauze. Panty hose and tapeless bandage (expandable with Velcro Straps) are good materials to use. Every two days, remove the bandage with the entire scab (which can be difficult around the border, but it is critical to remove all the dried serum). Aſt er 10-20 days, the granula- tion bed will mature and become smooth. At this point, overgrowth does not tend to be a problem (Photo 4). In Peppy’s case, the granulation tissue
surrounding the exposed bone reached skin level at day 11. However, we had to continue PRP treatment on the exposed bone site. T e delayed healing was due to denuded perios- teum when the injury occurred. Stage 3: Use a heavy paper towel sprayed
with wound wash with a light wrap. Apply continued next page continued next page
Illustration by Rebekah DiGiacomo
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