Management of avulsion wounds with exposed bone

Degloving injury of the distal aspect of the limb in a horse and preventing bone sequestrum formation using multiple, partial depth cortical fenestration

Exposed or denuded bone is a common complication of wounds of the distal aspect of the limb. This clinical report describes the treatment of an extensive laceration of the right hindlimb of a 12-year-old Hungarian Warmblood Horse gelding, which was managed initially by application of hydrogel dressings to enhance autolytic debridement, subsequently, by cortical fenestration of the denuded cortical bone and by stimulating the production of granulation tissue to cover the exposed bone. An early radiographic sign of sequestrum formation (discrete changes in the outer cortex) was not seen after the injury. Six weeks later, the wound was completely covered with vascularized, healthy-appearing bed of granulation tissue, which was prepared for grafting using the punch technique. A reinforced bandage was applied for the following 7 weeks; the grafts were accepted by granulation tissue. The horse was discharged 20 weeks after admission and the owners were advised to maintain stall rest with hand walking for two weeks. Four years later the owner reported that the wound had completely healed with a good cosmetic outcome and the horse was being used in a carriage.

Complications of equine wound management and dermatologic surgery

Complications of wounds and cosmetic surgery can be accurately managed with a combination of timely surgical and medical intervention to ensure the best possible outcome. The lack of soft tissue protection and a large quantity of susceptible synovial, tendon, ligament, and neurovascular structures make early and meticulous evaluation of limb wounds critical. Skin grafting is usually used following a period of open wound management and after healthy granulation tissue formation. Penetrating wounds of the abdomen or thorax have a guarded prognosis resulting from the ensuing potential for infection and pneumothorax. Gunshot wounds limited to the skeletal muscles have a good prognosis, whereas injuries that involve vital organs decreased survivability.

The modified Meek technique as a novel method for skin grafting in horses: evaluation of acceptance, wound contraction and closure in chronic wounds

REASONS FOR PERFORMING STUDY

The acceptance of skin grafts in horses is unpredictable and the final cosmetic result can be disappointing. Besides movement and infection, graft failure is often caused by chronic inflammation, inherently present during second intention healing of limb wounds in horses. In human burns affected by infection and inflammation, the acceptance of the island skin grafts of the modified Meek technique appeared to be better than meshed sheet skin grafts.

HYPOTHESIS

The percentage take of Meek micrografts is higher than of other techniques; and rates of both wound contraction and epithelialisation are increased.

METHODS

Large traumatic limb wounds of 13 horses healing by second intention were grafted using the modified Meek technique. Photographs of the wounds were taken at set intervals. Wound areas, and areas of acceptance and rejection were determined using a digital image post processor (Scion Image). The percentages of take, wound contraction and epithelialisation were calculated.

RESULTS

The initial mean wound area was 7500 mm2. Graft acceptance was mean +/- s.d. 93.7 +/- 5.9%. Wound closure was due to contraction (55.2 +/- 11.1%) and epithelialisation (44.8 +/- 11.1%) and resulted in a 96.7 +/- 3.6% reduction of the initial wound area 29.1 +/- 6 days after grafting. All wounds showed functional and cosmetic healing.

CONCLUSIONS

The method for skin grafting in horses achieved higher percentages of take than reported previously and consistent cosmetic and functional results. The grafts increased not only the rate of epithelialisation but also had a strong positive effect on wound contraction, resulting in rapid closure and smaller scars.

POTENTIAL RELEVANCE

The modified Meek technique proved to be a novel technique for skin grafting equine wounds in clinical practice, which can be performed easily. The molecular background of the increase of wound contraction by the grafts may provide a clue in the search for medicinal stimulation of wound contraction during second intention healing.