Page 680 - Adams and Stashak's Lameness in Horses, 7th Edition

646 Chapter 5

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A B
Figure 5.52. (A) An OC lesion of the caudal aspect of the glenoid cavity (arrowheads). This horse was grade 3 out of 5 lame. (B) An OC
lesion on the caudal humeral head (arrows). This horse was lame at the walk and had significant muscle atrophy.
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moderate success. In a more recent report of 14 horses
treated conservatively, 7 became sound with conserva-
tive treatment. 52
Surgical cases should be selected carefully because of
the generalized pathologic changes that are present in
many cases. However, surgery benefits some horses even
when secondary changes are present. 10,29 With very
severe degenerative changes, the prognosis is poor and
surgery is not recommended.
While arthroscopic surgery is the preferred approach
for treating these lesions, 10,71 the technique is not easy,
and it is particularly difficult in adult horses. In most
instances the cartilaginous changes extend beyond the
limits of the subchondral abnormalities seen on radio-
graphic examination (Figure 5.53). Problems associated
with arthroscopic surgery in the shoulder usually involve
inadequate access to medially located lesions and
debridement of large lesions.
Figure 5.53. Postmortem view of the large OCD lesion of the
Prognosis caudal humeral head depicted radiographically in Figure 5.52B.
Arthroscopic access to medially located lesions or debridement of
Generally the prognosis with rest or surgery is con- large lesions such as this can be difficult and often results in a poor
sidered guarded, but this is somewhat dependent on the prognosis. Source: Courtesy of Dr. Gary Baxter.
horse’s intended use and the severity of the OC lesion.
Horses with mild to moderate OC have the best progno-
sis, and those with severe lesions usually remain lame. In OSTEOARTHRITIS (OA) OF THE
one report on the outcome of arthroscopic surgery on SCAPULOHUMERAL JOINT
11 horses, 7 became athletically sound, and follow‐up
10
radiographic examinations on those 7 indicated remod- OA of the SH joint is a relatively uncommon condition
eling and improved contour of the glenoid and humeral that can affect a variety of breeds, ages, and uses of
head. In another study, long‐term follow‐up on 35 horses. 32,40 Reports found a higher incidence of OA in
horses with OC of the shoulder treated arthroscopically Shetland ponies, miniature horses, and Falabella ponies,
40
found that 16 of 35 were successful. A more recent with a possible congenital cause. 19,22,53,76
study of 32 horses with shoulder OC (16 with bilateral Although the recognition and treatment of conditions
lesions) also reported a poor outcome. In this study, the associated with SH joint have improved, the diagnosis
lesions were graded mild, moderate, or severe using a of specific problems related to this joint remain a chal-
system that took into account lesion size and lesion lenge. As a result, some may require extensive diagnos-
32
severity. However, there was no difference in conserva- tic imaging, including arthroscopy, to make a definitive
52
tive versus arthroscopic treatment. diagnosis. Unfortunately, the delay in recognition of the