Page 687 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Proximal Limb 653

usually reluctant to bear weight initially, have difficulty caudal to the scapular spine in the angle formed by the
advancing the affected limb, and often have swelling over spine and the body. 20,47,90 Longitudinal fractures have
VetBooks.ir usually elicit a painful response. 3,20 Fractures of the scap- the fracture line staggered along the scapula. 55
been repaired using several narrow DCP placed across
the fracture site. Deep palpation and limb manipulation
Severely comminuted fractures or fractures of the distal
ular neck may also result in secondary suprascapular
nerve injury and signs of paresis in some cases. Chronic neck and those extending into the glenoid are very difficult
cases of more than 3 weeks’ duration usually exhibit var- to treat surgically with internal fixation. The configuration
ying degrees of atrophy of the muscles in the shoulder of the fracture and its close proximity to the shoulder
region and proximal antebrachium. As time passes, joint do not permit application of orthopedic implants.
40
swelling may become more apparent in the lateral shoul- Euthanasia is recommended in horses with extensive joint
der region as a result of muscle atrophy, healing soft tis- involvement and/or severe joint instability. 13
sues, and callus formation. A swinging and support limb
lameness is observed at a trot. Horses sustaining these
fractures should also be assessed for other problems such Prognosis
as fractured ribs and intrathoracic trauma. 20 The prognosis is good for fractures involving the
scapular spine with or without surgery for removal of a
sequestrum, and most horses can return to performance
Diagnosis after an adequate rest period. Young horses with nonar-
Radiographs of the region are needed for a definitive ticular simple or minimally comminuted fractures of the
diagnosis. Medial to lateral, ventrodorsal, and oblique body and proximal neck have a good prognosis for
cranial to caudal radiographic projections reveal most soundness after application of internal fixation. At the
fractures of the scapula. The study can be done while the 1‐year follow‐up of 2 horses that underwent internal
horse is standing in most cases. Some fractures through fixation, complete healing and return to full function
the body of the scapula can be difficult to image because were noted. 20,47 A longitudinal fracture of the scapula in
of the superimposition of the ribs and vertebrae over the a young horse resulted in soundness at 6 months after
55
scapula; in these cases the limb must be protracted to internal fixation. In adults, nondisplaced fractures of
obtain a diagnostic film. If a fracture is suspected but the body or neck may heal satisfactorily with conserva-
40
40
not observed, the horse should be confined to a stall and tive therapy. Horses with complete fractures in the dis-
radiographed again 10–14 days after injury. A scinti- tal neck, articular fractures, and severely comminuted
37
graphic exam can be performed prior to this to assist in fractures all have a poor prognosis for return to
the diagnosis. Some large, heavily muscled horses in performance. 13,37
severe pain may require general anesthesia to obtain
diagnostic radiographs. Stress fractures of the scapula
are diagnosed by nuclear scintigraphic exam and ultra- FRACTURES OF THE SUPRAGLENOID TUBERCLE
sonography after lower limb analgesia has been per- (TUBEROSITY)
formed to rule out a lower limb issue in racehorses that
are acutely lame after racing. Suprascapular nerve Fractures of the SGT can occur in a variety of breeds
28
15,16,27,75
injury can be difficult to detect by physical exam alone of horses and horses with a variety of uses. They
in the non‐weight‐bearing limb. Electromyography are relatively common, accounting for about 30%–50%
37,57
(EMG) can be helpful in assessing nerve damage at least of reported scapula fractures. Fractures of the SGT
7 days after the injury has occurred. 20 are often simple, intra‐articular, and usually affect horses
less than 2 years of age. 16,57,75 In contrast, one report on
STG fractures in 9 horses found 4 with comminuted
Treatment fractures and 6 of the 9 were in horses 3 years or older
(range 3–13 years). 37
Conservative Treatment Anatomically, the SGT serves as the proximal attach-
Fractures of the scapular spine generally do not ment for the biceps brachii muscle and two gleno-
require surgical intervention, and most heal by bone humeral ligaments that support the SH joint. The
union. On the other hand, fractures following a pene- coracoid process, which is the medial projection of the
trating wound may develop bone sequestra; in these tubercle, serves as an attachment for the coracobrachi-
cases surgery is recommended. Some minimally dis- alis muscle. The SGT and the coracoid process develop
placed nonarticular fractures of the scapular body and from a single center of ossification and fuse with the
neck or stress fractures may also be treated conserva- cranial portion of the glenoid cavity and the main body
91
tively with a good result. 13,28,40 Providing stall rest for of the scapula at about 10–12 months of age. Because
several months, taping the shoulder to the body wall to the fracture plane often courses along this growth
prevent abduction of the limb, and slinging cooperative plate, it has been suggested that this fracture may result
animals have been used successfully in some cases with- from a separation of the physis of the SGT in young
out articular involvement. 28,37,40 horses. 57

Surgical Treatment Etiology
Transverse fractures of the body and proximal neck Fracture of the SGT is most frequently associated
can be surgically treated with internal fixation in young with trauma to the cranial shoulder region. Because of
animals. 20,47,90 Stabilization is achieved with two dynamic its superficial location, it appears that the SGT is most
compression (DCP) bone plates applied cranial and susceptible to injury. In two reports most horses with