The document describes a case study of a 6-year-old quarter horse gelding that was found with a large wound on its right hind leg, believed to be caused by an injury on a fence. The veterinarian evaluates the wound, determines it does not involve any joints, debrides and sutures it closed. The veterinarian then provides aftercare recommendations including bandaging, antibiotics, and exercise restrictions to promote healing of the serious wound.

1. Resident Rounds
with AAEP Student Club
April 21st, 2014
Dane M. Tatarniuk DVM

2. Case Study
• Signalment
– 6 year old Quarter Horse gelding
– Will be a barrel racing prospect
– Found this AM in the pasture with wound
• Owner is on the phone and unsure what to do
– What other questions do you ask for history?

3. History
• Wound is located on right hind leg, front of the cannon
bone
– Appears really deep
– Approximately 4 x 12 inches
• Horse has not had any medications yet
• Not sure what horse hurt itself on, suspect the fence
• Horse was vaccinated last Spring
• No previous medical or lameness problems
• Horse is lame at the walk, appears to ‘knuckle’ over
onto fetlock, but still bearing full weight on limb

4. • What recommendations do you make to the
owner over the phone prior to you arriving
on-farm or horse coming to your clinic?

5. • Can administer NSAID for pain
– Depending on your time till you can attend to horse
– Non-steroidal anti-inflammatory
• Phenylbutazone (Bute) or Flunixin meglumine (Banamine)
– Usually avoid pain medication prior to subtle lameness exams; in this
case, important for horse
• Can cold-hose the limb
• Apply a compression bandage
– Shipping or standing wrap
– Cotton / Vetwrap / Elasticon
– Compression aides in decreasing contamination and helps coagulation

6. • If your concerned about a cannon bone
fracture, your on-farm and transporting the
horse, what would be an appropriate way to
splint the limb for transport?

7. • If your concerned about a cannon bone
fracture, what would be an appropriate way to
splint the limb for transport?
– Need 90 degree stability
– Lateral and plantar splint acceptable
– Use PCV pipe, wooden board, broom sticks, etc.
– Apply from foot up to point of the hock
– Tape splints to a bandage placed on the leg
– Or, can use ‘Kimzey’ pre-made splints

9. • Which way would you want the horse in the
trailer to face?

10. • Which way would you want the horse in the
trailer to face?
– Forwards,
• When applying the brakes to the truck/trailer unit,
momentum will put more weight on forelimbs instead
of hind.
– Opposite holds for forelimb injuries; place horse in
trailer backwards

11. • Horse arrives to your clinic, you place it in the
stocks.
– What do you want to do first?

12. • Horse arrives to your clinic, you place it in the
stocks.
– What do you want to do first?
• Systemic (Physical) Exam!
– Heart rate
» Pain
» Shock
– Resp. rate
» Pain
– Temperature
» Should be normal
– Mucus Membranes
» Hypo-perfusion
– Don’t forget the Zebra
• Primary Colic -> horse thrashes -> cuts itself

13. Wound evaluation…..

14. Wound evaluation: What anatomy are you looking at?

15. Wound evaluation: What anatomy are you looking at?

16. Wound evaluation: What anatomy are you looking at?

17. Wound evaluation: What anatomy are you looking at?

18. Wound evaluation: Where do the vessels run?

19. Wound evaluation: Where do the vessels run?

20. Wound evaluation: How proximal does the flexor tendon
sheath live?

21. Wound evaluation: How proximal does the flexor tendon
sheath live?

22. • Why is the horse knuckling over when it
walks?

23. • Why is the horse knuckling over when it
walks?
– Loss of long digital extensor tendon and lateral
digital extensor tendon
– Able to flex the fetlock
– Not able to extend the fetlock

24. • Why is the horse knuckling over when it
walks?
– Lacerated extensor tendons…low concern
– Lacerated flexor tendons…huge concern

25. What steps do you want to take next?

26. • Sedate your patient
– Safety first
– xylazine, romifidine, or detomidine
• +/- butorphanol
• Clip and clean
– Sterile lube over wound
– Clip hair out of way
– Clean gently with betadine or chlorhexidine and
saline

27. • Probe the wound with sterile instrument
– Hemostat
– Teat cannula
• Map out extent of dead space, depth of the
wound, feel for fracture lines,
• Can palpate with instrument to see if wound
extends into joint, but be gentle so that you
don’t accidentally make a closed joint, open

28. • So you palpate the wound,
– Feel tons of cannon bone exposed
– Some dead space that extends towards the hock joints
– Wound does not seem to extend towards the flexor
tendon sheath
• You have concern regarding the close proximity of
the wound to the hock.
– What do you want to recommend next?

29. • Three options:
– Radiographs with radio-opaque instrument inserted
• Visualize instrument in joint space
– Arthrogram
• Contrast injected into joint, then radiograph
– Joint Distention with sterile saline/carbocaine
• Check for leakage from wound
• What are the pro’s / con’s of each of these
methods?

30. • Before you perform anything, think about the
anatomy:
– What are the joints of the hock?

32. • You perform a radiograph with a teat cannula
inserted at the top of the wound:
Interpretation?

33. • You also distend the tarsal-metatarsal joint
with sterile saline, following a 10 minute
preparation of the skin.
– No leakage into the wound is noted, pressure on
the syringe plunger.
• What is the landmark to enter the TMT joint?

34. • Needle: 1.5 inch, 20 gauge
• Volume: 3 – 5 cc
• Tarsal-metatarsal joint:
– Injected on the plantar-
lateral aspect of the hock
– Needle is inserted
immediately above the head
of the lateral splint bone
– Needle is angled in a dorsal-
medial and distal direction

35. • So now that you have
confirmed that the
wound doesn’t extend
into the joint….
• Beyond sedation, how
are you going to provide
analgesia so that you
can repair this?

36. • Analgesia Options:
– Local ring block around the circumference of the
wound
• Lidocaine, Carbocaine (mepivicaine)
– Regional Limb Perfusion
• Tourniquet proximal to wound, inject ~60cc of
carbocaine/lidocaine into vein.
• “Bier block”
– Peroneal-Tibial nerve block
• Desensitizes most tissue from hock and below
– General Anesthesia
• If horse was too dangerous to work on standing
• Ketamine / Diazepam or Triple Drip
• Always a risk that the cannon bone could have a hairline
fracture – high risk for recovery

37. • What steps do you need to take to provide
this wound with the best chance to heal by
primary intention?

38. • What steps do you need to take to provide this
wound with the best chance to heal by primary
intention?
– Debridement of bone
• Curette or scrape off the exposed bone surface
• Take tissue to where it bleeds, remove contamination
– Debridement of soft tissue
• Remove any tissue that is black, purple, green, etc.
• Leave only healthy, bleeding tissue behind
• Trim edges of the flap of the wound 1-2mm
– Debride tendon
• Remove the ends of the tendon
• Let it undergo fibrosis via 2nd intention healing, or can
consider suturing it to expedite the process
– Immobilization

39. • Following debridement, good idea to lavage
the wound to remove contaminants
– Sterile saline
• Add in 10cc of 2% betadine solution / L
• Or, add in 25cc of 2% chlorhexidine solution / L
– Optimal pressure is 7-8 psi. Consider using 35cc
syringe with 18 gauge needle
– Alternatively, can use motorized wound irrigation
systems
• ie, Stryker

40. • What size of suture do you want to use?
• What type of suture material do you want to
use?
• What suture pattern do you want to use?

41. • What size of suture do you want to use?
– Larger is more resistant to tension.
– Anywhere from #0 to #2 should work OK
• What type of suture material do you want to use?
– Ideally, non-absorbable
• Prolene
– PDS would be acceptable as well
– Want monofilament, not multifilament
• What suture pattern do you want to use?
– Tension relieving
• Vertical mattress
• Near-far-far-near

43. • What do you want to say to the owners
regarding prognosis / time frame for healing?

44. • What do you want to say to the owners
regarding prognosis?
– A lot of these wounds, even with proper suturing,
will dehisce
– Always good to try and suture the wound as it acts
as a physiologic bandage
– If wound dehisce, it will still heal by 2nd intention,
however the time frame changes significantly
• 1st intention healing – 2 to 3 weeks
• 2nd intention healing – 2 to 6 months

45. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Medications?

46. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Medications?
• Systemic Antibiotic Options
– Trimethoprim sulfa
– Ceftiofur
– Penicillin / Gentamicin
• Consider Regional Limb Perfusion
• Anti-inflammatory
– Phenylbutazone

47. • Regional Limb Perfusion
– Place a tourniquet around the tibia, to occlude the
vasculature
– Inject antibiotic (such as amikacin), diluted in a
large volume of saline, into the vein
– High pressure in the vasculature, from the
tourniquet and large volume of medication,
increases extravasation of antibiotic out of vein
and into tissue
– Tourniquet kept in place for 20-30 minutes
– Attains antibiotic levels that are 5-15x the MIC of
common pathogens in the tissue / synovial fluid
– Minimizes systemic side effects, reduces cost

49. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Exercise Recommendations?

50. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Exercise Recommendations?
• Stall rest until suture removal
– If it holds
• Stall rest or small paddock rest if it dehisces and you
wait for second intention healing to occur

51. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Bandaging Recommendations?

52. • So now that you have repaired the wound, what
kind of aftercare do you want to recommend?
– Bandaging Recommendations?
• Wound bandage overlying the incision
– Non-adherant pad (Telfa)
– Held in place with white kling or elasticon
• Support bandage
– Important in first few weeks of healing
– Decrease edema
– Hock can be difficult to keep bandaged
• +/- Splint
– Decrease movement on suture line by keeping fetlock extended
– Hard to properly splint the hock such that it remains immobile
• Could also consider a bandage cast

54. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Suture removal?

55. • So now that you have repaired the wound,
what kind of aftercare do you want to
recommend?
– Suture removal?
• If it doesn’t dehisce sooner, then sutures can be
removed at 14 days
• For high tension wounds, consider staggering suture
removal
– Half taken out at 14 days
– Half taken out at 21 or 28 days

56. • Horse goes
home. At day 3,
the owner emails
you this picture:

57. • Day 6

58. • Day 11

59. • Day 14

60. • Day 16

61. • Day 30

62. • 5 weeks

63. • 8 weeks
• What has
happened to the
wound?

64. • 8 weeks
• What is
happening to
the wound?
– Proud-flesh
– “Exuberant
granulation
tissue”

65. • 9 weeks
• Few days post
trimming proud
flesh

66. • 12 weeks

67. • 16 weeks
• Owner reports
increase in
lameness, increase
in discharge
present

68. • Horse comes
into clinic for
evaluation.
• Radiograph is
taken. What is
your diagnosis?

69. • “Sequestrum”
• Necrotic bone
– Results from
concurrent
infection and loss
of blood supply
• Body is trying to
reject the
diseased bone
• Surgical removal
indicated

70. • Horse had removal of sequestrum 3 weeks
ago. Is recovering well. Wound still hasn’t fully
healed.
• QUESTIONS ?