Page 1061 - Adams and Stashak's Lameness in Horses, 7th Edition

Occupational‐Related Lameness Conditions 1027

because most are custom made, thus adding to the hygeine. 17,30 Various treatments have been described for
expense of routine hoof care. managing infectious pododermatitis, including topical
VetBooks.ir are frequently left unshod. Those left unshod and not hydrochloric acid, topical sulfa drugs and metronida­
Most draft horses not used for athletic use or pulling
application of caustic agents such as formalin and
zole, cryosurgery, and limited and aggressive surgical
trimmed regularly by a farrier are prone to overgrown
hoof walls. Overgrown hoof walls are prone to hoof debridement. The combination of limited surgical
cracks, which can involve the sensitive laminae, and debridement and topical application of metronidazole
poor hoof care in general can contribute to chronic foot results in the best outcome.
soreness and lameness (Figure 9.63). Surgical debridement can be performed under general
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anesthesia or while standing. Debridement under anes­
thesia is preferred because of improved visualization,
Subsolar Abscessation
lack of patient movement, and superior hemostasis.
Subsolar abscessation is common in draft horses. Standing surgical debridement is facilitated with intra­
Risk factors include inadequate hoof care and poor stall venous sedation (detomidine hydrochloride and butor­
hygiene. 8,12,13,27 Hoof testers should be applied to the phanol tartrate) and perineural anesthesia of the palmar
sole, hoof wall, and frog in an attempt to localize focal digital nerves. A hobble is secured around the pastern,
areas of pain. In some instances purulent discharge can and the leg is hoisted and secured with a rope held by an
be expressed with the hoof testers. Feet also should be assistant or attached to stocks. A tourniquet is essential
carefully evaluated for foreign body penetration. to control hemorrhage and improve visualization. All
Insensitivity to hoof testers does not preclude a diagno­ visible portions of abnormal frog and sole are resected
sis of subsolar abscessation. Draft horses believed to with a sharp hoof knife or scalpel blade. Following
have subsolar abscessation should have a palmar digital debridement, a paste of metronidazole tablets (equiva­
or abaxial sesamoid block performed to confirm the lent to a systemic dose, 15–30 mg/kg) is applied to the
diagnosis and aid in trimming of the foot and sole explo­ debrided foot. A sterile bandage is then placed on the
ration for an abscess. If necessary, affected horses should foot. A treatment plate aids postoperative management.
be restrained in shoeing stocks or sedated for examina­ Topical application of metronidazole is performed at
tion to facilitate foot examination. Inability to find an least once daily until the debrided area of the sole and
abnormal region of the sole following hoof trimming frog is completely cornified, which may take 6–8 weeks.
does not rule out a diagnosis of subsolar abscessation. Aftercare is time consuming and must be performed daily
Soaking the foot can help soften the sole and aid identi­ until the defect has completely cornified. Owners must
fication and drainage of subsolar abscessation. understand the absolute requirement for good foot hygiene
Affected horses should be treated with NSAIDs as following treatment. If the horse is placed back into the
needed to facilitate patient comfort. Most abscesses same unhygeinic conditions, the condition will most likely
resolve promptly with adequate drainage and do not recur. The prognosis following treatment is fair to good.
require antimicrobials. It is important to remove the
undermined sections of the sole involved in the abscess Sidebone
to ensure adequate drainage. The author recommends
placing a foot bandage initially. Once cornification Ossification of the collateral cartilage occurs to some
begins, a shoe with a treatment plate can be substituted degree in all draft horses. Fortunately, lameness related
for the bandage. The shoe can be removed following to sidebone is rare. Sidebone can be indicative of chronic
complete cornification of the sole defect, if desired, and foot lameness, even though it is not the primary cause
the horse returned to use. The prognosis for routine sub­ for lameness. All suspected cases of sidebone should be
solar abscessation is good. confirmed with diagnostic anesthesia to rule out other
It is a rare case (less than 5%) in which extensive more common disorders of the foot.
subsolar abscessation leads to the development of septic Radiographic findings compatible with sidebone
osteitis of the distal phalanx in draft horses. Radiography include complete to incomplete ossification of the col­
is required to determine the amount of the distal pha­ lateral cartilages. 21,22 Separate centers of ossification are
lanx involved. Debridement of the third phalanx is not unusual and should not be confused with a fracture
accomplished with the horse standing and is combined of the collateral cartilage. Bone‐phase nuclear scintigra­
with perineural anesthesia of the digital nerves. phy can be useful in determining the significance of col­
To access the distal phalanx, a portion of the sole lateral cartilage ossification to lameness. Corrective
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overlying the abnormal area must be removed, and all farriery is the treatment of choice for management of
abnormal bone should be curetted. The defect is packed sidebone. The foot should be balanced medial to lateral,
with sterile gauze and a sterile bandage is placed on the and a long‐toe, low‐heel conformation should be
foot. For large sole defects, a shoe with a treatment or avoided. Corrective shoeing should include a rolled toe
hospital plate should be considered to protect the sole with quarter clips to stabilize the foot, or a bar shoe
and facilitate foot hygiene. The prognosis for septic oste­ with clips can be considered. The prognosis for sidebone
itis of the distal phalanx is fair to good as long as 25% in confirmed cases is favorable. Nonresponsive horses
or less of the distal phalanx is involved. 3,10 can be considered for palmar digital neurectomy.

Infectious Pododermatitis Distal Phalanx Osteitis
Infectious pododermatitis (canker) is commonly Nonseptic osteitis of the distal phalanx is not unu­
diagnosed in horses housed in stalls with inadequate sual. Contributing factors include heavy body weight,