Page 107 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

82 CHAPTER 1

VetBooks.ir tissue, and complete closure of the wound may not create a horny spur. Avulsions created surgically to
expose an underlying structure usually leave suffi-
be possible. That part of the wound not closed is
then allowed to heal by secondary intention and may
mal lamellae are broken off and left on the surface),
require prolonged casting. In those heel bulb lac- cient epidermal structures (i.e. the tips of the epider-
erations in which the coronary band is affected, the so that they heal as partial-thickness wounds. Less
coronary band may be sutured in a similar manner frequently, the same may occur with naturally
to that used in the treatment of hoof wall avulsions occurring avulsions.
(see below). In all instances, tetanus prophylaxis,
NSAIDs, analgesics and perioperative antibiotics Clinical presentation
are advisable. Horses with hoof wall avulsions present either
acutely or chronically. Acute injuries demonstrate
Prognosis varying degrees of lameness and haemorrhage asso-
The prognosis for most heel bulb lacerations for ciated with the trauma. Chronic injuries can present
return to athletic activity is good. There is usually with a granulating surface plus or minus complica-
a residual scar that varies in size with the original tions associated with deeper structure involvement.
injury, the amount of granulation tissue that devel- Alternatively, the integument heals, but the abnor-
ops and the success of the closure. The prognosis mal structure of the wall causes altered function and
for wounds with involvement of deeper structures is lameness.
dependent on which structures are affected and how
severely injured or contaminated they are. Differential diagnosis
None.
HOOF WALL AVULSIONS
Diagnosis
Definition/overview The avulsion is obvious on presentation, but the
Hoof wall avulsions occur when a segment of the underlying damage may not be (Fig. 1.141). The
hoof wall becomes separated from the underlying coronary tissues and adjacent skin are assessed for
tissues. viability. Careful exploration is required to ascertain
which deeper structures, if any, are involved. Injury
Aetiology/pathophysiology to ligamentous or tendinous structures causes lame-
Hoof wall avulsions follow trauma to the wall that ness due to instability or loss of motor function.
causes it to fracture and a segment to become ele- Communication with synovial structures that is not
vated. Typically, this occurs in a distal to proximal obvious is confirmed by flushing the structure from
direction. The avulsion is classified as complete if a distant site. Radiography soon after the injury
the avulsed wall is completely detached from the will demonstrate any defects in the bone caused
foot, and partial if the avulsed wall is still attached, by the injury, and in chronic avulsions may show
usually along one border. The avulsion may be con- advanced pedal osteitis associated with the adjacent
fined to the hoof capsule, but usually involves the inflammation.
coronary band and the skin of the pastern. The
extent of underlying trauma is variable but may Management
include any of the underlying structures. The pat- Complete avulsions are treated like any other wound
tern of healing depends on the depth of the trauma. that is allowed to heal by secondary intention. They
Most naturally occurring avulsions extend deep to should be cleaned and debrided, dressed with appro-
the basement membrane of the epidermis and heal as priate topical antimicrobials and dressings, and ban-
full-thickness wounds. Full-thickness avulsions epi- daged. Systemic antibiotics are administered until
thelialise from the adjacent margin, so the nature of the wound surfaces are granulating, analgesia given
the new hoof wall varies accordingly. Occasionally, as needed and tetanus prophylaxis provided. If the
hoof integument grows up onto a pastern defect to foot is unstable because of the amount of wall lost,