ISSN 2398-2977      

MC/MT 2 and 4: fracture

pequis

Introduction

Pathogenesis

Etiology

  • External trauma: direct blow from kick or impact injury.
  • Internal forces: biomechanical stresses during fast exercise, such as hyperextension of the fetlock, and particularly associated with suspensory desmitis in distal fractures.

General

  • The lateral splint bone, particularly in the hindlimb, is more exposed to direct trauma especially from kicks.

Specific

Pathophysiology

Distal fractures

  • Usually occur at junction between proximal two thirds and distal one third of the metacarpal bone and less commonly metatarsal bone.
  • With age → interosseus ligament loses flexibility and splint bone becomes more brittle.
  • Stresses going around bends → hyperextension of fetlock → ligamentous traction (fibrous bands from distal end of bones to medial and lateral proximal sesamoid bones) and through the interosseous ligaments, on splint bones → fracture.
  • Suspensory desmitis Suspensory ligament: desmitis - midbody with marked enlargement → pressure on splint bone with modeling and progressive deviation of the distal part of the bone from the MC/MT 3 predisposing to fracture.
  • Direct trauma, from external impact in the lateral splint. Interference from the opposite foot is more common in the medial splint.

Mid and proximal fractures

  • Direct trauma, from external impact in the lateral splint, whilst interference from the opposite foot is more common in the medial splint, particularly if an exostosis is already present on the splint MC/MT 2 and 4: periostitis (splints).
  • Direct kick from another horse or kicking a stationary object → often open fracture → osteomyelitis Bone: osteitis - septic. Fractures are more likely to be comminuted and variably displaced. Closed and simple fractures are less common.
  • The proximal half of the fourth metatarsal bone is most commonly affected.
  • Occasionally racing stresses → axial compressive loading due to articulation with carpus → fracture. Exacerbated by conformational abnormalities Musculoskeletal: conformation, eg bench knees.

Diagnosis

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Mageed M et al (2018) Internal fixation of proximal fractures of the 2nd and 4th metacarpal and metatarsal bones using bioabsorbable screws. Aust Vet J 96 (3), 76-81 PubMed.
  • Lischer C J (2008) Fractures of the splint bones: the importance of soft tissue attachments. Equine Vet Educ 20 (7), 380-382 WileyOnline.
  • Jackson M, Furst A, Hassig M & Auer J (2007) Splint bone fractures in the horse: a retrospective study 1992-2001. Equine Vet Educ 19 (6), 329-335 VetMedResource.
  • Jenson P W et al (2004) Segmental ostectomy of the second and fourth metacarpal and metatarsal bones in horses: 17 cases (1993-2002). JAVMA 224 (2), 271-274 PubMed.
  • Harrison L J, May S A & Edwards G B (2001) Surgical treatment of open splint bone fractures in 26 horses. Vet Rec 128 (26), 606-610 PubMed.
  • Baxter G M et al (1992) Complete excision of a fractured fourth metatarsal bone in eight horses. Vet Surg 21 (4), 273-278 PubMed.

Other sources of information

  • Nixon A J & Fortier L A (2020) Fractures of the Small Metacarpal and Metatarsal (Splint) Bones. In: Equine Fracture Repair. 2nd edn. Ed: A J Nixon. Wiley Blackwell, USA.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code