Page 1025 - Adams and Stashak's Lameness in Horses, 7th Edition

Occupational‐Related Lameness Conditions 991

some mild lameness that are better felt than seen or Foot Pain
when the lameness is best seen under saddle. It has been Foot pain is the single most common cause of lame­
VetBooks.ir hidden by riders and some would be exacerbated by ness in performance horses. Assessment of foot pain
shown that some lameness can be unconsciously well
starts with the observation of its conformation. Low‐
such riders. Experience of the veterinarian with the
24
particular discipline plays a major role in the detections heel, long‐toe conformations, underrun heels, and later­
of such subtleties. This is especially true with dressage omedial imbalances predispose horses to soreness.
horses, when the veterinarian will also have to evaluate Evaluation of the symmetry of the collateral ligaments
the trainer and rider as they could be causing a particu­ of DIP joint and the presence of DIP joint effusion is bet­
lar gait irregularity or not be able to guide the horse ter done by palpation. Hoof testers are applied carefully
properly to perform a certain task. Having an experi­ over the heels and sole and across the frog and the heels.
enced rider available to help evaluate such a horse can Most of the lameness of the foot will respond to PD
prove invaluable. nerve blocks, although such a block is not completely
If the lameness cannot be localized, nuclear scintigra­ specific to the foot as it has been shown to diffuse and
phy may be used. If the lameness is localized with nerve block out lesions in the pastern area even when per­
29,37
blocks, the whole array of imaging modalities could be formed the most accurately. A positive PD nerve
used beginning with radiographs and ultrasound and block should be interpreted as the lameness had its ori­
when necessary cross‐sectional imaging such as mag­ gin somewhere in the foot or pastern area. A positive
netic resonance imaging (MRI), computed tomography DIP joint block will localize it to the coffin joint and the
(CT), contrast‐enhanced computer tomography (CECT), rest of the foot including the navicular apparatus and
10,36,37
and positron emission tomography (PET) scan. MRI the sole, excluding the heels.
performed standing has gained in popularity and is A positive navicular bursa block will localize the ori­
often repeated to follow and monitor pathology even in gin of the lameness to the navicular apparatus or the
38
competing horses. sole. A positive DFTS block if interpreted within 10
minutes should limit the origin of the lameness to its
content with DDFT lesions and sometimes distal sesa­
17
moidean ligament lesions found most commonly.
COMMON LAMENESS PROBLEMS
All three disciplines confounded, the most common
sources of lameness are: Heel Pain and Solar Pain
1. Foot pain, including heel pain, solar pain, DDFT Heel pain and solar pain are more common in the
within the foot, DIP joint synovitis/arthritis, collat­ event horses and jumpers than they are in dressage
eral desmitis of the DIP joint and navicular bone, and horses. Part of this is probably due to the type of sur­
associated ligament injuries faces they work on. Proper farriery guided with radio­
2. Lower hock pain graphs will often be sufficient. For solar pain, the use of
3. Suspensory desmitis (fore‐ and hindlimbs, origin, and full pads is often helpful. Pour‐on fillers are very popu­
branches) lar as well, but care must be taken not to over fill the
4. Axial skeleton: cervical, thoracolumbosacral, and shoe or under the plates, as it would cause undue pres­
sacroiliac pain sure on the sole. Full plates are commonly used on
5. Superficial digital flexor tendon (SDFT) and inferior hunter/jumper and dressage horses but pretty unpopular
check ligament injuries among the eventers as they can promote shoe
6. Fetlock osteoarthritis (OA) loosening.
7. Stifle injuries Heel pain and corns can be managed fairly well using
onion shoes (open shoe with wide flare at the heels).
There are marked variations regarding lameness Occasionally, in more severe cases of underrun heels,
problems not only between disciplines but also within loading the frog using dental impression material, taped
disciplines between high‐ and low‐level horses. in without a shoe for 4–6 weeks, may help to promote
28
Dressage horses are significantly more prone to proxi­ some heel growth in a more vertical direction.
mal suspensory desmitis (PSD) in the hindlimbs at both Alternatively using frog‐loading pads or a rolled heel
low and high level. Those competing at lower levels are can be useful.
more prone to navicular bone and associated ligamen­ Sheared heels affect mostly jumpers and starts often
tous (impar sesamoidean and suspensory ligament of insidiously. The medial heel is often displaced proxi­
the navicular bone) injuries. Elite dressage horses are mally. Floating the affected heel and improving break‐
more prone to distal hock OA than the low‐level over by setting the shoe back and adjusting the lateral
horses. High‐level show jumpers are more prone to medial balance will usually resolve the problem,
DDFT injuries within the DFTS and the foot. The low‐ although this process can take 6 months to a year.
level horses are more prone to navicular bone and Addition of a hoof supplement rich in Biotin seems to
associated ligament injuries. Both have a relatively speed up hoof growth and improve hoof wall quality
high incidence of distal hock OA. High‐level event but is most often already being used. 23,32
horses and high‐level jumpers are significantly more
prone than others to SDFT injuries. This is likely
related to the fact that strain of the SDFT increases Navicular Syndrome, DIP Joint, and DDFT Lesions
significantly with speed, fatigue, and height of the Navicular bone and associated ligament injuries,
fences being jumped. 5,26 DDFT lesions within the foot, DIP joint synovitis/arthritis,