Equis ISSN 2398-2977

Humerus: fracture

Contributor(s): Graham Munroe, Jeffrey Watkins

Introduction

  • Uncommon fractures because of short thick configuration and extensive muscular covering.
  • Cause: foals/weanlings usually secondary to falls or direct trauma; adults as a result of accumulated stress (microfracture(s)) or catastrophic race falls.
  • Signs: severe lameness with crepitation and instability at fracture site in complete fractures, marked soft tissue swelling.
  • Diagnosis: radiography (complete fractures)   Forelimb: radiography  ; scintigraphy (incomplete/stress fractures)   Bone: scintigraphy  .
  • Types: proximal humerus and greater tubercle; deltoid tuberosity; middle and distal diaphyseal; distal condylar and epicondylar.
  • Treatment: varies with fracture type and position.
  • Prognosis: varies with position, type and age; poor for complete diaphyseal in adults; good for stress fractures in adult.

Pathogenesis

Etiology

  • Kicks, falls, concentrated training regimes.

Predisposing factors

General
  • Concentrated training regimes.

Pathophysiology

  • Fractures resulting from direct trauma or impact injuries to upper forearm and shoulder regions.
  • Spontaneous failure in race as a result of accumulated stress and microfracture in caudal aspect of proximal metaphysis and distal aspect of cranial metaphysis.
  • Type of humeral fracture:
    • Proximal humeral head.
    • Greater tubercle.
    • Deltoid tuberosity - individual fractures rare - usually portions of greater tubercle also included.
    • Mid diaphysis - many are short to long oblique spiral fractures with ends over-riding and variable comminution in adults; many oblique fractures spiral proximocaudal to distocranial cortex   →   proximal fragment resting in the intercondylar region of distal humerus and limiting further over-riding.
    • Distal metaphysis.
    • Distal condyle/epicondyle.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references fromPubMedandVetMedResource.
  • Madron M, Caston S & Kersh K (2013)Placement of bone screws in a standing horse for treatment of a fracture of the greater tubercule of the humerus.Equine Vet Educ25(8), 381-385VetMedResource.
  • Markel M D, Nunamaker D M, Wheat J D & Sams A E (1988)In vitro comparison of three fixation methods for humeral fracture repair in adult horses.Am J Vet Res49(4), 586-593PubMed.

Other sources of information

  • Nixon A J, Watkins J P (1996)Fractures of the Humerus.In:Equine Fracture Repair.Ed: A J Nixon. W B Saunders, Philadelphia.


ADDED