ISSN 2398-2977      

Proximal sesamoid: fracture

pequis

Introduction

Pathogenesis

Etiology

  • Hyperextension of the fetlock during maximal loading   →   internal strength of the sesamoid is exceeded   →   fracture.
  • Sagittal fractures can occur in combination with other fractures, ie condylar fractures.

Pathophysiology

  • Tensile forces of the suspensory apparatus supporting fetlock (suspensory ligament, sesamoid bones and distal sesamoidean ligaments) in extension.
  • Maximal loading, eg during strenuous exercise   →   tensile forces on sesamoid bones and cyclical loading   →   fatigue failure. Exacerbated by fatigue at end of exercise/race.
Apical fractures
  • Distraction of suspensory fibers determines the degree of displacement - usually <¼ of the suspensory branch insertion involved.
  • Tension across fracture line delays healing may get   →   fibrous union   →    rationale for recommending surgery.

Midbody fractures

  • Middle third of bone - subdivided into proximal, middle and distal areas of the middle 1/3.

Abaxial fractures

  • Includes site of suspensory ligament attachment along abaxial ridge of palmar/plantar bone - usually non-articular.

Basilar fractures

  • Distal 1/3 and usually articular - non-articular fractures involve only a portion of the base, usually axially.

Comminuted or biaxial fractures

  • Fetlock breakdown   Proximal sesamoid: fracture 17 comminuted - LM radiograph    Proximal sesamoid: fracture 18 comminuted - oblique radiograph    Proximal sesamoid: fracture 19 comminuted - DP radiograph    Proximal sesamoid: fracture 20 comminuted - LM radiograph  :
    • Disrupted collateral ligaments, fascial attachments, suspensory ligament   →   distractive forces.
    • Hyperextension   →   fetlock strikes ground   →   direct trauma to sesamoid   →   fracture, may be open with neurovascular compromise.
  • Biaxial fractures (both lateral and medial sesamoids): weightbearing   →   hyperextension and severe fragment distraction.

Sagittal fractures

  • Axial margin, often with other fetlock fractures such as condylar fractures.

Foals

  • Sesamoid fractures are often seen in foals out running with the mare:
    • Usually occurs at <2 months of age.
    • Carry a good prognosis.
    • Treated with box rest +/- bandage.

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

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.
  • Brokken M T, Schneider R K & Tucker R L (2008) Surgical approach for removal of nonarticular base sesamoid fragments of the proximal sesamoid bones in horses. Vet Surg 37 (7), 619-624 PubMed.
  • Busschers E et al (2008) Surgical repair of mid-body proximal sesamoid bone fractures in 25 horses. Vet Surg 37 (8), 771-780 PubMed.
  • Anthenill L A et al (2007) Risk factors for proximal sesamoid bone fractures associated with exercise history and horseshoe characteristics in Thoroughbred racehorses. Am J Vet Res 68 (7), 760-771 PubMed.
  • Anthenill L A et al (2006) Association between findings on palmarodorsal radiographic images and detection of a fracture in the proximal sesamoid bones of forelimbs obtained from cadavers of racing Thoroughbreds. Am J Vet Res 67 (5), 858-868 PubMed.
  • Schnabel L V et al (2006) Racing performance after arthroscopic removal of apical sesamoid fracture fragments in Thoroughbred horses age <2 years: 151 cases (1989-2002). Equine Vet J 39 (1), 64-68 PubMed.
  • Schnabel L V et al (2006) Racing performance after arthroscopic removal of apical sesamoid fracture fragments in Thoroughbred horses age > or = 2 years: 84 cases (1989-2002). Equine Vet J 38 (5), 446-451 PubMed.
  • Rothaug P G, Boston R C, Richardson D W & Nunamaker D M (2002) A comparison of ultra-high-molecular weight polyethylene cable and stainless steel wire using two fixation techniques for repair of equine midbody sesamoid fractures: an in vitro biomechanical study. Vet Surg 31 (5), 445-454 PubMed.
  • Woodie J B, Ruggles A J & Litsky A S (2000) In vitro biomechanical properties of 2 compression fixation methods for midbody proximal sesamoid bone fractures in horses. Vet Surg 29 (4), 358-363 PubMed.
  • Bouré L, Marcoux M, Laverty S & Lepage O M (1999) Use of electrocautery probes in arthroscopic removal of apical sesamoid fracture fragments in 18 Standardbred horses. Vet Surg 28 (4), 226-232 PubMed.

Other sources of information

  • Bertone A L (1996) Fractures of the proximal sesamoid bones. In: Equine Fracture Repair. Ed: Nixon A J. W B Saunders, USA.

Related Images

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!