Page 1087 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness in the Young Horse 1053

with only a rasp to avoid excessive trimming. Glue‐on
shoes (Dalric, Advanced Equine Products, Versailles, KY)
VetBooks.ir minimize asymmetrical loading of the physis and pull the
with lateral or medial extensions also may be helpful to
limb inward or outward. The extensions are placed on
the opposite side of where the deformity goes (lateral
extension for varus deformities and medial extensions
for valgus deformities; Figure 10.18). Frequent reevalua­
tions (e.g. every 2 weeks) with or without radiographic
examination should be performed to monitor the pro­
gress of conservative therapy.
Confinement and minor foot trimming can correct
many foals with mild to moderate ALDs and should
always be considered as the initial therapy if possible.
However, aggressive and prolonged trimming may lead
to concurrent angular deformities elsewhere in the limb
that may worsen the overall condition of the foal. For
example, a secondary varus deformity of the fetlock
may develop in some foals with carpal valgus treated
4
conservatively. Conservative management is usually
not recommended or successful with a severe deformity
of any physis in any age foal. The asymmetrical loading
of the physis is usually beyond the physiologic limits in
these cases, making autocorrection unlikely. 17,32 In addi­
tion, a severe ALD has a greater likelihood of causing
permanent damage to the tarsal or carpal cuboidal
bones if not corrected early in life.

Surgical Treatment of Asynchronous Physeal Growth
Surgical treatment of foals with ALDs is directed
toward accelerating growth on the concave side or
slowing growth on the convex side. 4,5,15,18,19,32
Figure 10.24. Cross section of a fetlock varus deformity in a Hemicircumferential transection of the periosteum and
young foal with collapse of the medial aspect of the epiphysis periosteal stripping (HCTP+PS) is used to stimulate
(arrow). growth, and various forms of transphyseal bridging
(TPB) are used to retard growth.
Physeal growth has been reported to occur by stimula­
Conservative Treatment of Asynchronous tion of the physis with fan‐shaped stab incisions and
Physeal Growth
placement of needles directly into the physis. These
11
Conservative treatment of asynchronous physeal techniques were reported as another method to treat
growth usually involves a combination of time, exercise ALDs and as an alternative to HCTP+PS. The exact
11
restriction, and foot care in foals with mild to moderate mechanism contributing to physeal growth stimulation
ALDs. Under normal circumstances, most foals autocor­ is unknown but is thought to be a mechanical release of
rect their deformity because the bone grows faster on the the periosteal restraint of growth. However, there is
4,5
concave side and slower on the convex side (Wolff’s controversy regarding the true benefit of HCTP + PS. In
law). 14,17,32 This only occurs under physiologic loads, so practices where foals can be examined on a consistent
the goal of confinement is to minimize overloading of the basis, clinicians found that most correct on their own,
physis. Overactivity may cause or perpetuate physeal with only changes to the exercise regimen. This has
29
trauma and excessive loading, possibly preventing the been confirmed by two studies. A controlled model of
limb(s) from autocorrecting. Restricting the foal’s exer­ ALD demonstrated no benefit of HCTP + PS compared
cise by confining the mare and foal to a stall and run or with controls treated with confinement and hoof trim­
small paddock/pasture is usually adequate. Confinement ming. Another study in nine foals with naturally occur­
25
is usually continued until the limb has straightened. ring carpal valgus deviation reported that correction of
Foot trimming (or balancing) also may minimize com­ carpal ALD was not significantly corrected by
31
pressive forces on the physis. In foals with varus deformi­ HCTP + PS. These studies and observations have ques­
ties, the hoof does not wear as much on the medial side tioned whether HCTP + PS is a necessary surgical proce­
and becomes compressed on the lateral side. The oppo­ dure in foals with ALDs. However, many veterinarians
site occurs with valgus deformities. The goal of trimming remain convinced that it is beneficial because foals with
is to remove the hoof wall that is overgrown (trim the ALDs treated conservatively improve after HCTP + PS is
hoof on the side that the leg goes; inside hoof for varus performed. 4,11,18
deformities and outside hoof for valgus deformities) to TPB is effective and is currently the most reliable sur­
make the foot flat or balanced. 24,32 This should be done gical technique to correct limb deformities. However,