Page 1038 - Adams and Stashak's Lameness in Horses, 7th Edition

1004 Chapter 9

with a well‐controlled exercise program in which the sport of endurance compared with other disciplines.
intensity and duration of work is gradually increased Deep digital flexor tendinitis occurs less commonly than
VetBooks.ir ment in lameness and ligament healing based on serial the hindlimb in endurance horses. Clinical diagnosis is
SDF tendonitis but appears to have a predilection for
over 6–12 months. This is often guided by improve­
based on palpation and confirmed by ultrasonography.
ultrasonographic evaluations.
Thermography can be used to confirm regional hyper­
thermia associated with acute soft tissue injuries
Foot Lameness
(Figure 9.47). Similar to other soft tissue injuries, early
Foot conditions are common causes of lameness in topical ice therapy and systemic NSAIDs after rehydra­
endurance horses. If time permitted more routine use of tion are warranted. Rest duration, rehabilitation, and
the hoof tester at the vet gate examination during endur­ prognosis depend on lesion severity and location.
ance events, the AERC post‐ride statistic results men­
tioned above would likely be quite different. Often
evaluation of the digital pulse and comparison of its Other Causes of Lameness
pre‐ and post‐trot quality can be informative. Common Acute joint sprain is not uncommon and is often
conditions include foot bruising, corns, dislodged or influenced by the condition of the trail footing. Although
sprung shoes, and heel bulb trauma from overreaching the fetlock appears to be more commonly affected, slip­
or other sources of injury. ping on trail can potentially result in soft tissue injury of
Endurance horses are also subject to acute laminitis any other joint. Interference injury, especially of the
that may be related to repetitive concussive laminar medial fetlock of the hindlimb, is common, and occasionally
trauma or associated with systemic exertional disease lameness can result (Figure 9.48).
syndromes (e.g. heat stress, exhaustion, rhabdomyolysis, Splints can cause acute lameness and are likely more
and renal failure). Aggressive medical treatment for common during training, especially in horses with less than
acute laminitis is indicated in any endurance horse with ideal forelimb conformation. This condition typically
prodromal signs thereof (shifting weight, forelimb lame­ responds well to conservative treatment and rest. Recurrent
ness while turning, bounding digital pulses, etc.). Early lameness is uncommon unless there is impingement on the
treatment is important because consistent clinical prog­ suspensory apparatus that causes chronic desmitis.
nostic indicators are unclear. It is quite common for cer­ Chronic OA affecting the metacarpophalangeal and
tain horses to develop bruising at the coronary band and hock joints is not uncommon. Prognosis in horses with
subsequent horizontal hoof cracks as the hoof grows significant degenerative disease is guarded with the
out that serve as a timeline of when laminitis may have exception of distal tarsitis, which may respond well to
occurred at previous competitive rides (Figure 9.46). intra‐articular corticosteroids, enabling continued
The majority of these horses complete the ride and do work.
not develop lameness; thus, it is unclear whether this Catastrophic fractures have become more frequent in
truly represents a laminitic event. Very rarely subsolar endurance horses coincident with the increasing speeds of
hematoma formation can cause acute lameness that can competition, especially in the Middle East and at interna­
mimic acute traumatic laminitis in endurance horses. tional venues. Fractures are most common in the forelimb,
especially condylar fractures involving the metacarpo(tarso)
4
Tendinitis phalangeal joint and, less commonly, the proximal phalanx.
Stress‐related bone injury is presumed to play a role in frac­
Superficial digital flexor (SDF) tendinitis is a com­ ture development in endurance horses. While no large‐scale
mon cause of lameness in endurance horses, especially
in the forelimb. While tendinitis occurs less commonly
in the hindlimb, it appears to be more prevalent in the

Figure 9.47. Thermographic image of an endurance horse with
Figure 9.46. Hemorrhage at the coronary band from a recent trauma of the right front medial fetlock region. Source: Courtesy of
100‐mile competition on hard footing in an endurance horse. Dr. Ken Marcella.