Page 670 - Adams and Stashak's Lameness in Horses, 7th Edition

636 Chapter 5

Diagnosis more horses were euthanized (44.4%) than treated with
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surgical (24%) or conservative (32%) management.
Radiography is used in most cases to confirm the frac-
VetBooks.ir ture and define the configuration. A slightly oblique cases were euthanized. 96
In another retrospective study, 9 of 22 humeral fracture
medial to lateral projection with the limb held in exten-
sion usually provides the information needed for epiphy-
seal and shaft fractures. In most cases the study can be Nonsurgical Management
done in the standing sedated horse. Foals can be Nonsurgical management has been used successfully
restrained in lateral recumbency with the affected to treat stress fractures; incomplete or complete nondis-
limb down to obtain a diagnostic lateral projection. placed or minimally displaced nonarticular fractures;
Craniocaudal views of the distal humerus and oblique minimally displaced Salter–Harris type I and II fractures
views of the proximal humerus can be obtained in most of the proximal and distal physis; deltoid tuberosity
standing sedated horses and foals. Craniocaudal views of fractures; complete displaced proximal and distal trans-
the entire proximal humerus are more difficult to obtain, verse and oblique fractures; and complete displaced diaphy-
and general anesthesia may be required. seal transverse, short, and spiral oblique fractures. 14,28,56,66,96
Multiple radiographic views may be needed to iden- In two reports a better outcome was obtained in foals
tify fractures of the greater tubercle and deltoid tuberos- compared with adults. 14,96 Long transverse and oblique
ity. Obtaining a cranioproximal to craniodistal oblique fractures can be reasonably stable when the caudodistal
projection of the proximal portion of the humerus in a aspect of the proximal fragment rests within the epicon-
standing horse often highlights the long oblique frac- dylar groove. Shorter oblique fractures have less stabil-
tures of the greater tubercle that are not evident on a ity and usually require internal fixation. Contraction of
mediolateral view. In one study of deltoid tuberosity the heavy musculature surrounding the humerus also
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fractures, the authors noted a cranial 45° medial to cau- helps stabilize the fracture while it heals. Of 19 cases of
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dolateral oblique view assisted in diagnosis. In this fracture of the deltoid tuberosity, local wound care alone
study 86% of the fractures were identifiable with ultra- resulted in a return to athletic function without lame-
sonography alone. ness in 13 of the 14 available to follow‐up. 28
Horses with stress fractures often have a grade 3/5 Nonsurgical management consists of 3–6 months’
lameness in the affected limb that improves quickly after stall rest, with periodic radiographic or nuclear imaging
the initial injury. Manipulation of the elbow and shoul- reevaluation of the fracture for healing. 66,80 Initially,
der often exacerbates the lameness, yet diagnostic anes- incomplete or complete nondisplaced fractures can be
thesia is not useful. A definitive diagnosis of stress maintained on an overhead wire to minimize the chance
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injuries requires nuclear scintigraphic as well as radio- of developing a complete fracture. 56,66,80
graphic examination. The caudodistal cortex or the cau- Complications are not common but may include
doproximal cortices are most commonly affected, but contralateral-limb laminitis and angular limb deform-
fractures of the cranioproximal and craniodistal cortices ity, radial nerve damage, and nonunion. 14,96 No adverse
also may occur. 4,52,67,80 Radiography may identify callus effects attributable to shortening of the humerus, such
formation along the affected cortex in chronic cases. For as a shortened stride or a straightened elbow joint,
more information on humeral stress fractures, refer to were reported in successfully treated horses in these
the section on Thoroughbred racehorses in Chapter 9. studies.

Treatment Surgical Management
Currently three options are considered when manag- Unfortunately, the current techniques of dynamic
ing a horse with a humeral fracture: nonsurgical (conserva- compression plating, intramedullary fixations, and cer-
tive) management with prolonged stall rest, surgical reduction clage bands or wires do not have sufficient strength to
followed by stabilization, and euthanasia. 11,14,55,66,80,84 Of provide adequate stability in adult horses. 11,55,56
the two treatment approaches, nonsurgical management Intramedullary pinning, bone plating, and ASIF or
appears to provide the best outcome compared with sur- interlocking intramedullary nailing or rush pins have
gical approaches for most nonarticular incomplete or been used to successfully treat foals and ponies with
complete humeral fractures, no matter what the age of humeral fractures. 14,15,23,66,91 Bone plates have been
the horse (Figure 5.42). 14,96 applied to repair nonarticular humeral fractures in foals
In one report, 7 of 10 horses treated nonsurgically and yearlings. 14,61,86 At present most reports describe the
were able to be ridden 5–12 months after the diagnosis use of DCP or LC‐DCP; there are few if any reports of
was made, and only 1 of 3 surgically treated (2 rush the use of LCP for humeral repairs. The interlocking
pins, 1 lag screws) cases was considered sound for intramedullary pin has been used successfully in foals
riding. The ages of the horses that were treated non- weighing up to 220 kg. In larger foals a cranial plate is
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96
surgically ranged from 2 to 60 months (mean also applied to augment the reduction.
21 months). In another study, conservative treatment Unstable and extensive greater tubercle fractures of
resulted in 9 of 17 cases being considered successful; 4 the proximal humerus may require removal or internal
became athletically sound and 5 were pasture sound. fixation with lag screws. 1,60,94 Extensive fractures of the
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The horses that were treated nonsurgically ranged in deltoid tuberosity, although uncommon, also can involve
age from 1 week to 15 years (mean 3 years). Euthanasia the greater tubercle of the proximal humerus. Surgical
still remains a commonly selected option. In a retro- intervention is required to reestablish cortical continuity
spective study done on 54 horses with humeral fractures, of the bicipital groove and reestablish the tensional