WOUND HEALING IN HORSES Flashcards
What are the three wound healing phases in horses?
- Acute inflammation
- Cellular proliferation
- Matrix synthesis and remodelling

explain acute inflammation
Consists of two phases
- Vascular response
- vasoconstriction
- vasodilation; diapedesis of cells, fluids and protein
- platelets and coagulated blood involved in clot formation.
- Cellular response
- leucocytes recruited by vasoactive mediators. Passage of inflammatory cells through endothelium.
- cellular influx begins within minutes; neutrophil numbers increases.
What are the three phases of cellular proliferation
Fibroplasia, Angiogenesis and Epithelialisation
Describe fibroplasia
Fibroblast migration.
aided by: cytokines (PDGF and TGF-beta) and proteinases.
once arrived switch function to protein synthesis, primarily type III collage initially.
describe angiogenesis
Endothelial cells migration (about 2nd day following injury)
capillary sprouting: solid structure, once fused with neighbouring structure forms arcade and becomes canalised
mediated by: Growth factors (PDGF, VEGF) and various over adhesion molecules.
describe epithelialisation
commences 24-48h after injury.
centripetal movement of residual epithelium below clot participates with wound closure
mediated by integrin receptors on epithelial cells
once wound covered inhibited by laminin.
explain matrix synthesis and remodelling
myofibroblast allows contraction of wound
gradual conversion to type I collagen to return the ratio to 4:1/
list and describe the 4 wound classifications
- clean
- not common only seen in surgery
- non-traumatic or infected
- no break in sterile technique
- no inflammation encountered - clean-contaminated
- not common, seen in colic surgery
- GI or resp tracts entered without spillage
- urinary tract entered with no infection noted
- minor break in sterile technique - contaminated
- major break in technique
- gross spillage from GIT
- fresh traumatic wound
- low number of bacteria that aren’t causing infection in tissues. - Dirty
- acute bacteria inflammation encountered
- traumatic wound with retained devitalised tissue foreign bodies, faecal contamination and/or delayed treatment.
list and describe the 4 types of wound closure
- Primary closure
- delayed primary closure
- secondary closure
- second intention healing
Describe factors affecting wound healing
WOUND LOCATION
- Distal limb vs body, wounds on distal limb have impaired healing
- reason partially unknown but may be due to decreased blood supply
- distal limb injury tends to heal at half the time of flank injury
SYNOVIAL INVOLVEMENT
- slows healing
BONE/TENDON INVOLVEMENT
- until infection is gone in tendon the wound will continue to fester along
FOREIGN BODY
MOVEMENT
- will slow wound healing needs to be immobilised
BLOOD SUPPLY
- needs blood supply.
Give examples of improving wound healing
immobilisation;
- bandage, splint, cast
Control infection;
- regional perfusion techniques e.g. gentimicin
Maggot debridement therapy;
- remove them after a week or a few days as they may eat flesh as well.
Describe differences in wound healing between ponies and horses
PONIES:
- stronger and shorter inflammatory process
- increased number of PNM and ROS
- wound healing faster due to greater contraction and increased TGF-beta
HORSES
- faster granulation tissue formation but more chaotic and subject to persistent inflammation
- Continued fibroblast proliferation for longer
- early inflammatory response isn’t as strong as ponies
- slower wound healing.
describe the types of wound closure.
Primary Closure: Immediate suture closure
Delayed Primary Closure: Closure 2-5d after injury tissue debridement and wound lavage before closure
2ndary Closure: Closure 5d after injury, granulation tissue and epithelialised edges excised at time of closure.
2nd intention healing: healing by granulation tissue, wound contracture and epithelialisation.
list the steps in wound management
- clip hair from surrounding area
- Clean wound
- Debridement and lavage (high pressure flow of sterile saline)
- Suture; if necessary
- Drainage; if necessary
- Immobilisation
may do IV infusion of antibiotics.
identify treatment options to maximise wound healing
SUTURE CHOICE:
- monofilament, synthetic material ideal
- simple interrupted better then continuous
- tension relieving patterns e.g. vertical mattress, near-far-far-near.
