Page 536 - Adams and Stashak's Lameness in Horses, 7th Edition

502 Chapter 4

advantage of softening impact during locomotion. Rigid and early laminitic horse. An additional goal is to restore
materials may transfer weight‐bearing more effectively the relationship between the hoof capsule and the distal
VetBooks.ir cause focal pressure under the margin of the distal pha- placement, severity of lameness, the way in which the
phalanx. The management varies with the type of dis-
but are discouraged because they are more likely to
horse moves, and stability of the distal phalanx. The
lanx and pain and should therefore be generally avoided
or only used with caution. treatment of dorsal capsular rotation, symmetrical distal
The moment or torque about the DIP joint at rest can displacement, and asymmetrical displacement are con-
be decreased by elevating the heels. This decreases the sidered separately.
tension in the DDFT and therefore the tension in the
dorsal lamellae. This is more likely to benefit horses that Hoof Care in the Treatment of Horses with Rotation
have or are about to develop capsular rotation and is
unlikely to help (and may hurt) those that have or are The challenge of treating horses with rotation, usu-
prone to distal displacement. The arm of the extensor ally both capsular and phalangeal, is to realign the
moment at break‐over can be shortened by moving the phalangeal axis while simultaneously realigning the
point of break‐over palmar to the dorsal margin of the hoof wall with the parietal surface of the distal phalanx
toe (Chapter 8). This may be done by rasping the ground (while also controlling pain). Complications are com-
surface of the hoof wall while being careful to preserve mon and must be managed as they occur. The mainstay
the integrity of the white line or incorporating it into a of treatment is hoof care, but various surgical techniques
supporting device. Commercial plastic cuff and pad may be required.
combinations conveniently combine a wedged heel and Trimming and shoeing of the foot should be planned
eased break‐over (i.e. the NANRIC Ultimate, NANRIC based on radiographic observations. 54,62 Dorsopalmar
Co., Lawrenceburg, KY). and mediolateral radiographs should both be taken (as
Treatment must be titrated to the severity of the dis- described earlier) prior to shoeing. The guiding princi-
ease. Currently it is not routinely possible to assess the ples are as follows:
degree of injury to the lamellae, so the severity of the dis-
ease for each type of displacement is usually determined 1. Realign the phalangeal axis by trimming
2. Preserve the thickness of the sole
by clinical parameters such as heart rate, the severity of the
lameness, response to treatment, and radiographic 3. Move the break‐over in a palmar/plantar direction
4. Reduce the tension in the DDFT
changes. In the early stages of therapy, the intensity of
therapy initiated depends on the severity of clinical signs 5. Recruit weight‐bearing by the ground surface of the
foot depending on tolerance and type of shoeing to
(i.e. not all horses need all of the measures described).
However, in the horse that has undergone treatment and be used
appears to be improving, it is advisable to gradually dis- The trim should aim to restore the angle that the
continue treatments, withdrawing one treatment measure solar margin of the distal phalanx forms with the ground
at a time followed by 2–3 days of observation. In more to between 0° and 5° (in severe cases, it may be prefer-
mildly affected horses, treatment may be discontinued able to aim for 5° vs. 0°). At the same time, the sole
over 1–2 weeks. However, in severely affected horses, the depth should be preserved to at least 15 mm wherever
treatment should be tapered off over 6–8 weeks as the possible. In horses in which the dorsal sole is greater
treatment switches to that for the chronic laminitic patient. than 15 mm in depth, the trim is along a single plane
from the dorsal margin of the sole all the way to the
heels (Figure 4.74A). However, in most horses with rota-
Treatment of Active and Stable Chronic Laminitis
tion, the depth of the dorsal sole is significantly less than
The objectives for maintaining stability of the distal 15 mm due to the distally displaced dorsodistal aspect of
phalanx and pain control are similar to that of the acute the distal phalanx.

A B
Figure 4.74. (A) When the depth of the sole exceeds approximately sole is less than 15 mm, which is common in horses with rotation, the
15 mm across the sole, the alignment of the distal phalanx with the goal is to preserve the dorsal sole, yet still realign the distal phalanx for
solar surface of the foot can be achieved by trimming the entire ground shoeing. The palmar ground surface is trimmed (dashed line) on a
surface of the foot on a single plane (dashed line). (B) When the dorsal different plane to the dorsal half (which is not trimmed).