Page 1162 - Adams and Stashak's Lameness in Horses, 7th Edition

1128 Chapter 11

If shod, the basic trim begins by drawing a line gories based on their configuration and location. More
across the widest part of the foot and trimming the detailed information regarding distal phalanx fractures
VetBooks.ir plane as the frog. This can generally be accomplished touching lameness to a moderate to severe supporting limb
can be found in Table 4.1.
heels of the hoof capsule such that they are on the same
Affected horses show a variation in lameness from a toe
in most cases. The toe length is reduced dorsally to the
line drawn across the foot, resulting in approximate lameness that is acute in onset. Trotting on a hard surface
proportions on either side of the line. 22,24 If significant generally accentuates the lameness. Increased digital
heel is removed from an upright or club foot, heel ele­ pulse, sensitivity to hoof testers over the sole, and swelling
vation may be necessary to accommodate the resultant around the coronary band can be noted. With time, the
stresses placed on the DDFT. When a fissure is present sensitivity of the hoof testers generally becomes localized
in the central frog sulcus, it should be stabilized to to the area distal to the fracture. Clinical signs are similar
decrease the vertical movement of the heels that will to those displayed with a subsolar abscess or a severe sub­
inhibit healing. This can readily be accomplished by solar bruise. Once the clinical examination has isolated a
applying a straight‐bar shoe. foot‐related problem and no abscess is isolated, high‐
quality radiographs will often confirm a fracture. Nuclear
scintigraphy often reveals the fracture in the acute stage
Medical
before it becomes apparent on radio graphy. It is the
Any detached areas of necrotic horn on the surface of author’s opinion that digital nerve anesthesia should not
the frog should be debrided with a sharp hoof knife. The be used prior to radiographs in acute lameness situations,
frog is cleaned initially by soaking the foot in a saturated even if clinical signs are minimal, because full weight‐
(add salt until it no longer dissolves) solution of Epsom bearing on the foot may cause the fracture line to increase
salts (MgSO ). Topical antiseptics/astringents including in length, become comminuted, or cause nonarticular
4
2% iodine, merthiolate, chlorohexidine, and various fractures to become articular. See Chapter 4 for further
copper sulfate solutions can be applied on a daily basis. information on distal phalanx fractures.
Topical antibiotic ointments/solutions appear to be unnec­
essary, and caustic preparations that contain phenol, Farriery
formalin, or formaldehyde should be discouraged.
External stabilization of the hoof can be used to treat
some horses with distal phalanx fractures. The distal
daily aftercare
phalanx can be stabilized within the hoof capsule using
Horses should have their feet cleaned and the frogs one or two methods: a bar shoe with a continuous rim
brushed vigorously with a stiff brush after which an or contiguous clips or a foot cast. A straight‐bar shoe
astringent is applied on a daily basis. 1,3,41 If there is a fis­ with a continuous rim attached to the perimeter of the
sure present in the central sulcus, the area above the fis­ shoe, encasing the basal border of the hoof wall, pre­
sure should be flooded with the antiseptic/astringent vents or limits expansion of the hoof wall, decreases the
solution to allow penetration into the fissure and then independent movement of the heels, and stabilizes the
packed with a folded gauze pad. The horse should be kept distal phalanx. The solar surface of the foot is packed
in a dry, clean stall, bedded on wood shavings or sawdust, with impression material before applying the continu­
and turnout should be in a dry paddock. Exercise should ous rim shoe for a number of reasons. First, when any
be encouraged to maintain/improve the normal physiol­ form of restrictive shoe is applied to the outer hoof wall,
ogy of the foot. Repeated trimming of any detached horn the foot tends to contract, especially at the heels, over a
on the frog may be required until the infection is con­ short period of time. Solar/frog support in any form
trolled. Routine farriery should be scheduled every 4–5 appears to lessen this process quite markedly. Second,
weeks paying close attention to the trim, the foot confor­ the distal phalanx descends in a distal palmar/plantar
mation, the frog, and the integrity of the soft tissue struc­ direction when weight is placed on the foot with no
tures of the foot. Prevention is always superior to form of counterpressure below. Also, if the fracture is
treatment; therefore, emphasis should be placed on good articular with the larger fragment being displaced ven­
farriery as the primary means for preventing this disease. trally, this added support may increase the stabilization
in this direction. The full rim shoe is relatively easy to
construct and has advantages over the bar shoe with
Fractures of the Distal Phalanx
side clips, which are placed randomly and apply limited
Fractures of the distal phalanx are not an uncommon focal pressure to the outer hoof wall.
injury in equine practice. Although this fracture is quite The second method is to apply a foot cast. Foot casts
common in racehorses, it can occur in any breed. Causes are relatively simple to apply and effectively stabilize the
include racing on a hard track, kicking an unyielding distal border of the hoof capsule. In preparation for
object, landing on blunt objects while exercising, and pen­ casting, the hoof capsule should be clean and trimmed if
etration of the hoof with a foreign body. The involvement needed. A piece of casting felt is cut to size to cover the
of the DIP joint influences the outcome of the case and heel bulbs both medially and dorsally, and second piece
future soundness. Fractures that involve the articular sur­ of felt is applied to the proximal pastern just distal to
face of the DIP joint usually account for increased lame­ the fetlock. A roll of 2‐ or 3‐inch fiberglass casting tape
ness, a longer convalescence, and a poorer prognosis for a is then wound around the perimeter of the ground sur­
return to full athletic soundness. On the other hand, non­ face of the foot. The concavity of the sole and the frog
articular wing fractures carry a much better prognosis. sulci should be filled with impression material to distrib­
Distal phalanx fractures are classified into 7 distinct cate­ ute the load of weight‐bearing across the solar surface of