Page 688 - Adams and Stashak's Lameness in Horses, 7th Edition

654 Chapter 5

SGT fracture had a history of falling or direct trauma to
the shoulder. 37,75 Overflexion of the shoulder leading to
VetBooks.ir chialis tendons that attach to the SGT has also been pro-
increased tension on the biceps brachii and coracobra-
posed as a mechanism for this fracture. Fracture of the
2
SGT has occurred in several horses with suprascapular
nerve paralysis following surgical removal of a piece of
bone from the cranial border of the scapula. 15,16

Clinical Signs
A history of trauma resulting in severe lameness that
improves rapidly is common. 16,37,75 This rapid improve-
ment may be the reason that this fracture is not initially
diagnosed in some instances and that recognition of the
problem only occurs after the horse remains lame longer
than expected or when muscle atrophy becomes
prominent. 37,75
In acute cases swelling is usually apparent over the
point of the shoulder, and palpation generally elicits a
painful response. Crepitation may also be appreciated in
some cases. At a walk, the horse typically retains the
ability to extend the SH joint, but the cranial phase of
the stride is markedly shortened. A lameness score of
3–4 out of 5 is typical in the acute phase. As time passes, Figure 5.61. Fracture of the supraglenoid tubercle of the
swelling over the point of the shoulder diminishes, and scapula with moderate displacement.
palpation may reveal a firm, nonpainful swelling over
37
the point of the shoulder. Movement of the tubercle
can be perceived in some cases. Varying degrees of mus- the development of secondary OA caused by joint
cle atrophy are usually apparent in chronic cases. Some incongruity.
37
horses may also exhibit signs of suprascapular or radial Removal of the fragment involves dissection of the
nerve paralysis. Intra‐articular anesthesia of the SH joint tendinous attachments of the biceps brachii and coraco-
may not improve the lameness. 37 brachialis muscles of the SGT. Excising the fractured
SGT decreases the pain created by fracture movement
and prevents further joint damage that develops from
Diagnosis impingement of the fragment on the articular surface of
9
Radiography is required to make a definitive diagno- the humeral head. Surgical excision of the SGT appears
sis of the fracture (Figure 5.61). Generally, the fracture to be best suited for most chronic fractures and for
is simple or comminuted and intra‐articular. 15,37,75 comminuted articular fractures. 75,98 In one report, 4 of 7
Calcification of the biceps tendon may also be associ- horses returned to performance, including 1 racing
ated with fracture of the SGT. Electromyographic Thoroughbred that had a successful career at a reduced
37
studies are sometimes needed to rule out neurogenic performance level. Caudal luxation of the scapula can
atrophy of the affected muscles. occur with excision of the fractured SGT. 15
Several methods of internal fixation consisting of
various combinations of interfragmentary compression
Treatment with lag screws and tension band wires have been used.
Several options can be considered for management of Cancellous bone screws placed in lag fashion across the
SGT fractures. The selection of the management fracture gap were reported to be unsuccessful in 2
approach depends on the nature and duration of the horses. Internal fixation using Kirschner wires in com-
57
fracture, economics, and the expectation of performance bination with cerclage wire placed in a figure‐8 pattern
level of the horse. to stabilize the fracture fragment was used successfully
57
Conservative management consisting of the adminis- in one case. Stab incisions made through the tendon of
tration of NSAIDs and prolonged stall rest for 3–4 the biceps brachii muscle to place bone screws in a lag
27
months followed by pasture turnout for 6–9 months fashion was also used successfully in one report. Bone
may be selected in some cases. Horses with nonarticular plating of SGT fractures has also recently been advo-
or minimally displaced intra‐articular fractures respond cated. Internal fixation has limited success, particularly
best to this approach and may be able to return to their in heavily muscled horses; the porous bone in the scapu-
intended use, depending upon the degree of OA that lar neck does not hold screws adequately, fracture reduc-
may develop. 16,37,75 The use of platelet‐rich autologous tion is difficult, and fixation fails due to the tension
plasma has been described as an adjunctive therapy to exerted by the biceps brachii tendon. 2,15,16 Partial or
conservative management. 21 complete transection of the biceps tendon has been
Surgical management of horses with SGT fractures advocated to eliminate the tension on the fracture frag-
consists of either surgical removal of the SGT fragment ment and prevent implant and bone failure. 2,15 Trauma
or internal fixation with or without transection of the and damage to the suprascapular nerve can occur due to
biceps brachii tendon. The goal of surgery is to prevent the surgical procedures mentioned.