Intro to equine wound management

Question 1

4 Phases of Wound Healing

Answer 1

1. Hemostasis phase
2. Inflammatory phase
3. Proliferative phase
   (i) Fibroplasia
   (ii) Angiogenesis
   (iii) Epithelialisation
   (iv) contraction
4. Remodelling phase

Question 2

Hemostasis phase of wound healing

Answer 2

▪Initial vasoconstriction
▪First 5-10 minutes
▪End point: formation of blood clot

Question 3

Inflammatory phase of wound healing

Answer 3

▪ Also called debridement phase
▪ 1-3 days after injury

Question 4

Which stage of wound healing do we have the greatest influence on? How?

Answer 4

• the acute inflammatory stage

▪ Debridement
▪ Irrigation
▪Good haemostasis ▪Adequate drainage
^ all greatly hasten wound healing

Question 5

Proliferative phase of wound healing

Answer 5

▪Filling of the wound bed with healing tissue (fibroblasts)
▪Few days
▪ Lasts for weeks after injury
(i) Fibroplasia
(ii) Angiogenesis
(iii) Epithelialisation
(iv) Contraction

Question 6

Speed of epithelialisation

Answer 6

▪Slow
▪ flank wounds: rate of 0.2mm/day
▪ limb wounds: rate of 0.09mm/day

Question 7

What is epithelialisation inhibited by?

Answer 7

▪ infection
▪ desiccation of the wound surface (drying out, therefore bandage choice can impact this stage)
▪ exuberant granulation tissue
▪ repeated dressing changes (every time you change the dressings you’ll take off the top ayer of cells

Question 8

When does wound contraction start and how long does it last for?

Answer 8

▪ Starts week 2 after wounding
▪ Continues for several weeks

Question 9

Why is wound contraction important?

Answer 9

▪ Accelerates closure
– Can reduce original SA by 40 to 80%
– Can occur at 0.75mm/day
▪ Increase cosmesis of scar
▪ Less need for epithelialization

Question 10

Remodelling phase of wound healing

Answer 10

▪ From 2 weeks after wounding
▪Ends in formation of scar tissue one - two years later
▪ Ensure strength, integrity and function of new tissue

Question 11

Wound healing in ponies (cf horses)

Answer 11

▪1 & 2 intention healing more rapid in ponies
▪Quicker & more intense inflammatory response
▪Pony wounds more resistant to infection
▪Greater contraction due to higher number of leukocytes recruited
▪Less wound dehiscence
▪Fewer bone sequestrate
▪Less exuberant granulation tissue (‘proud flesh’) due to more intense & less prolonged inflammatory phase

Question 12

Wound prep - clipping

Answer 12

• always clip
• removes foreign material
• makes it easier to stitch
• minimises infection and contamination
• allows much better assessment of the wound

Question 13

Clipping size

Answer 13

• 5-10cm margin is good

Question 14

Wound cleaning

Answer 14

▪0.05% chlorhexidine (gluconate) 4%
– Superior antibacterial activity than povidone
iodine
– 12.5 mL in 1L of saline

▪0.1-0.2% povidone iodine
– Inactivated by organic material
– Evidence for dilute povidone iodine use in contaminated wounds
-> 1- 2 mL in 1L of saline

▪OR just water
– Like hose a very contaminated wound down first, to remove the bulk of debris and contamination
– But water itself is toxic to fibroblasts, so you don’t want to clean a wound with water once you’ve got rid of the obvious contamination

(don’t need to remember quantities)

Question 15

Wound prep order

Answer 15

• Restraint, inc sedation
• Clean and controlled environment (wash box / stable)
• Remove gross contamination
• LA (can usually do digital exploration without but for stitching up and closing a wound need it)
  – Bupivicaine, mepivicaine
  – Perineural anaesthesia if limb
• Gel (KY jelly) and clip (5-10cm margins)
• Remove gel with sterile saline
• Assess

Question 16

BEVA Primary Care Clinical Guidelines: Wound management in the horse

Answer 16

• clean, potable tap water can be considered instead of saline for savaging wounds
• use of povidone iodine may be beneficial for contaminated wounds

Question 17

Synoviocenthesis of the DIP joint (dorsal perpendicular approach)

Answer 17

• the needle is inserted at the proximal edge of the coronet, approx 0.75 inches (~2cm) lateral or medial to the midpoint of the coronet (i.e. at the edge of the extensor ligament)
• the needle is directed distally, perpendicular to the bearing surface of the hoof

Question 18

Synoviocenthesis of the DIP joint (dorsal approach)

Answer 18

• needle is inserted near or on the midline, perpendicular to the skin surface immediately proximal to the coronary band

Question 19

Synoviocenthesis of the PIP joint (dorsal approach)

Answer 19

• needle is inserted on the dorsal midline about dcm distal to an imaginary line drawn between the medial and lateral eminences for attachment of the collateral ligaments on the distal end of the proximal phalanx and is directly obliquely distally and medially
  OR
• needle is inserted proximal to the imaginary line between eminences and directed slightly distally and slightly medially

Question 20

Synoviocenthesis of the digital flexor tendon sheath

Answer 20

• the digital synovial sheath can be entered at any of the pouches along its length
• even when the digital synovial sheath is not effused it often can be entered on the palmar aspect of the pastern between the proximal and distal digital annular ligaments, where the DDFT lies close to the skin

Question 21

Synoviocenthesis of the metarcarpo/metatarsophalangeal joints (Dorsal approach)

Answer 21

• to enter the dorsal pouch insert the needle under the lateral edge of the common digital extensor tendon at or slightly above the palpable joint space and direct the needle medially and parallel to the frontal plane of the joint

Question 22

Synoviocenthesis
Metarcarpo/metatarsophalangeal joints (Palmar/Plantar approach)

Answer 22

• palpate and identify the lateral aspect of the palmar/plantar pouch of the fetlock joint
• the pouch is bordered by the palmarodistal/plantardistal aspect of the 3rd metacarpal/tarsal bone; the dorsal edge of the lateral branch of the suspensory ligament; the distal end of the 4th metacarpal/tarsal bone; and the lateral, proximal sesamoid bone

Alternatively
- hold the limb in flexion
- insert the needle into the lateral aspect of the palmar/plantar pouch

Question 23

Synoviocenthesis of the carpus

Answer 23

• palpate the radiocarpal and inter carpal joints medial to the palpable tendon of the extensor carpi radialis muscle
• insert the needle into the radiocarpal joint, medial to the palpable tendon on the extensor carpi radialis muscle
• insert the needle into the inter carpal joint, medial to the palpable tendon of the extensor carpi radialis muscle

Done with the limb flexed.

Question 24

Synoviocenthesis of the tarsus (tibiotarsal joint)

Answer 24

• palpate the tibiotarsal joint distal to the level of the medial malleolus of the tibia
• insert the needle just medial or lateral to the visible saphenous vein, 1-1.5 inches distal to the level of the palpable medial malleolus
• the joint capsule is superficial and thin

Question 25

Synoviocenthesis of the tarsus (tarsometatarsal joint) (plantarolateral approach)

Answer 25

• needle is inserted above the head of the 4th metatarsal bone and directed in a dorsomedial direction
• approaching the tarsometatarsal joint by directing the needle dorsodistally in a sagittal plane may increase accuracy of arthrocentesis of this joint

Question 26

Synoviocenthesis of the stifle (femoropatellar compartment)

Answer 26

• needle is inserted between the middle and medial patellar ligaments or between the middle and lateral patellar ligaments, 1-1.5 inches proximal to the palpable proximal aspect of the tibial tuberosity
• needle is inserted parallel to the ground through the large fat pad between the patellar ligaments and joint capsule