Acute and Chronic Laminitis: an Overview
Individualized approach based on adherence to principles produces best results
Reprinted with permission from the American Farrier Journal.
Original printed in the 2007 December issue of the American Farriers Journal
By Stephen E. O'Grady, DVM, MRCVS
Acute and chronic laminitis is a
frustrating and often disheartening
condition to manage.
Having the opportunity to observe, treat
and shoe laminitic horses for many years
gives one a unique prospective into this disease. The biggest challenge to the
veterinarian and the farrier is to improve
function in a foot or feet that may have
potential, substantial and possibly
permanent structural changes.
It should be remembered from the
onset, that it is the extent of the lamellar
pathology (damage) that will influence
our ability to treat a given case of laminitis, not the treatment regimen that
is used. If this were not a fact, we would
not read on a weekly basis in equine journals
or horse-care magazines about some
horse that was lost to laminitis.
Another problem we need to overcome
is that treatment regimens for both
acute and chronic laminitis generally
remain empiric and are based on the past experience of the attending clinician or
farrier. Each case of laminitis should be
approached on an individual basis noting
the predisposing cause, the foot conformation
and the structures of the foot that
can be used to change the forces placed
on the hoof. Perhaps our approach to
treatment should be based on mechanical
principles, aimed at what we want to accomplish on a given laminitic foot
rather than any one shoeing method.
When we approach a case of acute
laminitis, we encounter three problems.
1. We have no way of knowing the extent
of the laminar damage present and
whether this damage will be permanent
when the animal first shows signs of
acute laminitis. The number of horses
that have suffered a severe laminitic
episode that we are able to treat successfully
is small and the window for treatment
once clinical signs are observed is also relatively small. The damage to the
lamellae that occurs during the developmental
stage of laminitis often precedes
the onset of pain and lameness.
In other words, structural damage is
present for a period of time before the
horse, owner and veterinarian are aware
that a problem exists.
Laminitis often originates from an
organ system remote from the foot such
as the gastrointestinal, respiratory, reproductive
or endocrine systems. Therefore,
treatment during the acute stage always
needs to aggressively address the initiating
cause of laminitis or — if treatment
of the cause was initiated before the
onset of laminitis — should be continued.
|FIGURE 1.The arrow denotes the point of breakover after the toe has been beveled on the ground surface.
|FIGURE 2. Lateral and dorsopalmar radiographs of a horse with severe distal displacement taken 10 days after the onset of symptoms.
|FIGURE 3. A dorsopalmar radiograph showing displacement of the distal phalanx in a horizontal plane.
|FIGURE 4. A schematic drawing of a radiograph used for realignment of distal phalanx. It shows the lines drawn parallel to the solar surface of the distal phalanx (Line 1) and the line drawn parallel to the dorsal surface of the distal phalanx as well as the desired position of the point of breakover (Point B).
2. We have no practical means to counteract
the vertical load of the horse's
weight that is placed on its feet. In other
words, we have no method that allows us
to take weight off the inflamed lamellae.
If the horse is shod or if the horse stands
on a hard surface, weight bearing is transferred
from the perimeter of the hoof
wall onto the compromised lamellae.
In acute laminitis, it may be appropriate
to remove the shoes if the horse is
shod and apply some type of deformable
material to the solar surface of the foot
such that the sole, bars and frog in the
palmar/plantar section of the foot
become load sharing with the hoof wall.
Frog pressure has become ingrained in
the veterinary and farrier literature as a
method to support the weight of the
horse. The anatomy of the bottom of the
horses' foot, the horny frog (which varies
in thickness) and the digital cushion
above it, both are readily compressible
structures under pressure.
When pressure is placed over the frog,
it quickly deforms, compresses and the
interface between the outer surface of
the frog and the solar surface of the distal phalanx (P3) is diminished. These structures
can be irreversibly damaged by frog
pressure and the animal will often feel
more discomfort. To counteract the forces acting on the bottom of the foot,
it may be more advantageous to recruit
the entire solar surface of the foot instead
of relying on one structure.
This can be accomplished by
applying either thick styrofoam, one of
the deformable impression materials or
placing the horse in sand. Applying shoes
in the acute stage of laminitis, in my
opinion, has not been shown to offer any
3. The distractive force placed on the
lamellae by the deep digital flexor tendon
(DDFT). In the acute stage this can be
decreased to some extent by moving the
breakover in a palmar /plantar direction.
A line is drawn across the solar surface
of the foot dorsal to the frog and a rasp
is used to bevel the foot in a dorsal direction
from this line. This effectively
moves the breakover palmarly, decreases
the moment on the dorsal lamellae and
may lessen the forces created by the
DDFT (Figure 1). Raising the heels
excessively in the acute stage has been advocated by some but should be done
with caution, as there is no scientific
proof of a beneficial effect.
Laminitis as a consequence of systemic disease such as gastrointestinal
problems, respiratory disease, retained
fetal membranes or contralateral limb
laminitis results in distal displacement
(sinking) of the distal phalanx ( Figure 2).
In this case the entire lamellae attachments
are damaged, allowing the distal
phalanx to sink uniformly within the
Raising The Heels
There is minimal involvement of the
deep digital flexor tendon during this
sinking process. A common treatment
regimen for distal displacement is to raise
the heels with the theory that it decreases
stresses on the DDFT, a practice that I
have not seen to be successful. Moving
the breakover back and placing a uniform
layer of a deformable impression material
on the bottom of the foot or placing
the horse in sand may be a better option.
Recently, I have applied wooden shoes
to horses with acute laminitis that are
expected to rotate or sink. These shoes have the border of the ground surface at
the toe and sides cut on an angle and the
results are very encouraging. They will be
described later in the text.
Baseline radiographs consisting of a
lateral and dorsopalmar view (to diagnose
unilateral displacement of the distal
phalanx in a horizontal direction) should
always be taken during the initial examination
of acute laminitis. They can be
used to determine previous damage, to
follow the progression of the disease and
as a guide to trimming and shoeing the
horse at the appropriate time.
Rehabilitation of the horse with
chronic laminitis is not a “cookbook”
process as affected horses with chronic laminitis will vary from horse to horse
and foot to foot and our understanding of
the disease is still vague. However, the
understanding of digital mechanics has
improved and technological advances in
shoe design and materials and techniques
continue to expand.
Chronic laminitis by definition means
that the distal phalanx (P3) has displaced
within the hoof capsule. The distal
phalanx can rotate downward at the toe,
rotate to either side (laterally or medially)
or it can totally displace (sink) within
the hoof capsule. Rehabilitation of the
horse with chronic laminitis will again
depend on the amount of viable lamellae
that remain intact, the conformation of
the foot and the ability to realign the
distal phalanx within the hoof capsule.
The question is often asked as to when
a horse with chronic laminitis should be
shod. The guidelines are:
- The horse has become more comfortable.
- The horse is on decreasing medication.
- The foot is stabilized i.e. there have been no further radiographic changes in the foot for a given period of time.
I have never been successful nor have
I observed improvement in the laminitic state when having to use local anesthesia
in order to lift the horses foot and apply
a shoe before the foot has stabilized.
The lateral radiograph is often the
only film taken for evaluating chronic
laminitis but it does not allow identification
of asymmetrical medial or lateral
distal displacement. Therefore, the
author considers it crucial that a
dorsopalmar (AP) radiographic projection
is included as part of the radiographic
study for either acute or chronic
laminitis. High quality radiographs are
required to visualize the osseous structures
within the hoof capsule as well as
the hoof capsule itself.
Radio-opaque markers can be used
to determine the position of the distal
phalanx in relation to surface landmarks.
The radiographic features of chronic
laminitis are well documented.
The following observations from the
lateral radiograph are important in determining
the prognosis and guiding treatment:
- The thickness of the dorsal hoof wall.
- The degree of dorsal capsular rotation.
- The angle of the solar surface of the distal phalanx relative to the ground.
- The distance between the dorsal margin of the distal phalanx and the ground and the thickness of the sole.
The dorsopalmar radiograph is examined
to determine the position of the
distal phalanx in the frontal plane.
Asymmetrical distal displacement of the
distal phalanx on either the lateral or
medial side is present if an imaginary
line drawn across the articular surface of
the distal interphalangeal joint or
between the solar foramens of the distal
phalanx is not parallel to the ground, the
joint space is widened on the affected
side and narrowed on the opposite side,
and the width of the hoof wall appears
thicker than normal on the affected side (Figure 3).
Finally, radiology will form the guidelines to be used in realigning the distal phalanx and applying any type of farriery (Figure 4).
Trimming and shoeing has always
been the mainstay of treating chronic
laminitis and is directed at reducing andor
removing the adverse forces on the
compromised lamellae. In considering
hoof care in horses with chronic
laminitis, there are three goals for
- To stabilize the distal phalanx within the hoof capsule.
- To control pain.
- To encourage new hoof growth to assume the most normal relationship to the distal phalanx possible.
Realignment of the third phalanx to
create a better relationship of the solar
surface of the distal phalanx with the
ground is used as the basis for treating
chronic laminitis. Realignment of the
distal phalanx should promote and
produce hoof wall growth at the coronet
and sole growth under the distal phalanx.
Applying any type of shoe following
this procedure should complement the
realignment of the distal phalanx and
further decrease the forces on the
The principles applied to all shoeing
methods used in treating chronic
laminitis are to recruit ground surface,
reposition the breakover palmarly and
to provide heel elevation as needed. Our
shoe of choice is usually some type of
wide web aluminum shoe with heel
elevation either incorporated within the
shoe, in the form of rails or a heel wedge
insert if an adequate heel base is present.
Deformable impression material is
applied between the branches of the shoe
to increase the surface area and redistribute
the load. Breakover can easily be
cut into the shoe in the appropriate place
using a grinder. The center of rotation can
be used for accurate placement of the
shoe on the foot.
|FIGURE 5.This is a wooden shoe with impression material. The black arrow signifies the widest part of the foot. Red line denotes the point of breakover on the ground surface of the shoe.
|FIGURE 6. A wooden shoe applied to the foot with screws placed against the foot at the heels to act as struts to accommodate fiberglass-casting tape.
Recently this writer has been very
successful using a wooden block cut in
the shape of the foot with the border of
the ground surface cut on an angle of at
least 45 degrees (Figure 5). The foot is
trimmed appropriately to address
realignment, impression material is
formed to create an interface between
the solar surface of the foot and the
wooden shoe, heel elevation is used if
necessary and the shoe is applied atraumatically
using screws, casting tape and
or a composite (Figure 6).
With this procedure flat, even pressure
is placed across the palmar section of
the foot and all the mechanics are placed
in the block while preserving the hoof
Deep digital flexor tenotomy remains
a very useful procedure for treating
chronic laminitis. I consider this surgery
necessary if the margin of the distal
phalanx has prolapsed through the sole
or on those cases that fail to stabilize once they begin displacing.
As stated earlier, two of the main
detriments when treating chronic
laminitis are the weight of the horse and
the distractive force of the DDFT. One of
these detrimental forces can be removed
through this surgery. but knowing when
to use it may pose a dilemma. It is often
necessary to use this procedure in order
to realign the distal phalanx.
|FIGURE 7. A radiograph showing marked rotation with a flexural deformity involving the DIP joint. A DDF tenotomy is necessary to realign the distal phalanx.
Further indications for this surgery
are progressive rotation, persistent pain,
minimal hoof wall and/or sole growth
and secondary flexor apparatus contracture.
If a marked flexural deformity
involving the distal interphalangeal joint
(DIP) is present, this is an indication of
shortening of the musculotendonous unit
and a release procedure is necessary to
accomplish realignment of the distal
phalanx (Figure 7).
It has to be emphasized that if a deep digital flexor tenotomy is utilized, it must be accompanied by realignment of the distal phalanx to decrease the adverse forces on the lamellae. Following a DDFT tenotomy, the second phalanx will move distal and palmarly relative to the distal phalanx (P3). This concentrates the load on the palmar soft tissue structures of the foot rather than redistributing the load on the solar surface of the distal phalanx.
The author has found it helpful to use
a shoe or a cuff to extend the ground
surface beyond the heel and add a few
degrees of heel elevation. This will
realign the digital axis and appears to
improve the clinical perimeters (comfort,
hoof capsule changes, sole growth, etc.)
Unfortunately, many of the treatment
regimens — both medical and farriery —
that are used to treat acute and chronic
laminitis are based on tradition, theoretical
assumptions that a given treatment
should work and anecdotal evidence that
a certain type of treatment has worked on
There are no controlled studies
comparing efficacy of the numerous treatments in use nor is there any scientific
proof that one treatment is superior
to another. What are well documented
are the forces and mechanics applicable
to the equine foot. As clinicians (veterinarians and farriers), we may be better
served by a thorough knowledge and
understanding of the anatomy, physiology
and function of the hoof.
Understanding the foot in a mechanical
sense may allow us to better apply our
Treatment of laminitis has to be a
group effort equally shared between
veterinarian, farrier and owner. The intent
of this paper is not to discourage treatment
of laminitis but to create expectations
that are realistic, humane and based
on the cause of the disease, amount of
lamellar damage, pain, duration and the
financial constraints invo l ved in
At the onset of treating chronic
laminitis, certain guidelines should be
outlined to indicate the efficacy of the chosen treatment method along with a
reasonable timeframe for improvement.
These guidelines could be a change in
stance, decreased digital pulse, increased
comfort, horn growth at the coronet, sole
growth, etc. If the desired improvement
is not observed or the condition gets
worse, the overall farriery methods
should be reassessed and changed where
With severe laminitis cases, we are
often unable to rehabilitate the horse to
where it has an acceptable quality of life.
The main reason being that there are
insufficient soft tissue structures
remaining within the hoof to achieve
I think it is important from a humane
perspective to know when to discontinue
treatment that has not been effective.
Often we persevere with various treatments,
put the horse through much
unnecessary suffering only to achieve an
It is unlikely that there will ever be a
single drug or other line of therapy to
treat acute or chronic laminitis so our
research efforts need to be directed
Dr. Steve O'Grady is both a veterinarian
and a farrier. He operates
Northern Virginia Equine in Marshall,
Va., which is an equine podiatry practice
and also offers a podiatry
consulting service. He is the chairman
of the AAEP veterinarian-farrier
committee and a member of the
International Equine Veterinarians
Hall of Fame.
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