Equis ISSN 2398-2977

Navicular bone: syndrome

Synonym(s): Navicular bursitis, navicular disease, podotrochleosis, podotrochlitis

Contributor(s): Olin Balch, Patrick Colahan, Simon Curtis, Martin Gough, Helen Herinckx, Vetstream Ltd

Introduction

  • Cause: multifactorial, hoof and pastern conformation, concussion, breed and activity associated.
  • Signs: bilateral forelimb lameness   Musculoskeletal: gait evaluation  .
  • Diagnosis: clinical presentation, perineural analgesia, radiography   Forelimb: radiography  .
  • Treatment: corrective shoeing and analgesics may help. Tiludronate in the early stages, neurectomy for selected chronic cases.
  • Prognosis: guarded.
Print off the Owner factsheets on Navicular bursitis and Navicular disease to give to your clients.

Pathogenesis

Etiology

Predisposing factors

General
  • Trimming/shoeing which induces a broken-back axis to the hoof pastern region.
  • Chronic heel bruising.

Pathophysiology

  • Recently, advances in diagnostic imaging techniques, eg MRI scanning, have improved understanding of the pathological changes involved.
  • Two main theories:
    • Biomechanics (currently more popular):
      • Repetitive trauma to the navicular bone during chronic repetitive loading by pressure from the deep digital flexor tendon   →   the development of a bursitis and an inflammatory process   →   lameness.
      • Cumulative cyclic loading   →    sagittal bending of the navicular bone   →    microdamage   →    adaptive failure of the bone (low bone mass, poor osteocyte connectivity, low osteophyte density).
    • Vascular:
      • Interruption of circulation to and from navicular bone   →    remodeling.
      • Thromboses within the navicular bone   →    hypertension   →    remodeling.
  • Upright pastern conformation accompanied by long toe/low heel conformation (underrun heels) affects biomechanical relationship of the deep digital flexor tendon and navicular bone predisposing to navicular damage.
  • Chronic pain in the heels may   →    heel unloading   →    increased force over navicular bone   →    degenerative changes in navicular bone.

Timecourse

  • Once established the lesion is progressive.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource
  • Coomer R, Thomas H & McKane S (2013)Current concepts of navicular syndrome: diagnosis and treatment.In Pract35(6), 325-335 VetMedResource.
  • Dyson S, Murray R, Schramme M & Blunden T (2011)Current concepts of navicular disease.Equine Vet Educ23(1), 27-39 VetMedResource.
  • Rijkenhuizen A B M (2006)Navicular disease: a review of what's new.Equine Vet J38(1), 82-88 PubMed.
  • Grewal J S, McClure S R, Booth L C, Evans R B & Caston S S (2004)Assessment of the ultrasonographic characteristics of the podotrochlear apparatus in clinically normal horses and horses with navicular syndrome.JAVMA225(12), 1881-1888 PubMed.
  • Denoix J M, Thibaud D & Riccio B (2003)Tiludronate as a new therapeutic agent in the treatment of navicular disease: a double-blind placebo-controlled clinical trial.Equine Vet J35(4), 407-413 PubMed.
  • Dik K Jet al(2001)Relationships of age and shape of the navicular bone to the development of navicular disease - a radiographical study.Equine Vet J33(2), 172-175 PubMed.
  • McGuigan & Wilson A M (2001)The effect of bilateral palmar digital nerve analgesia on the compressive force experienced by the navicular bone in horse with navicular disease.Equine Vet J33(2), 166-171 PubMed.
  • Wilson A Met al(2001)The force and contact stress on the navicular bone during trot locomotion in sound horses and horses with navicular disease.Equine Vet J33(2), 159-165 PubMed.
  • Willemen M A, Savelberg H H C M & Barneveld A (1999)The effect of orthopedic shoeing on the force exerted by the deep digital flexor tendon on the navicular bone in horses.Equine Vet J31(1), 25-30 PubMed.
  • Wilson A M (1997)Treatment of navicular disease.Vet Rec141(23), 608 PubMed.
  • Wright I Met al(1998)Gross histologic and histomorphometric features of the navicular bone related structures in the horse.Equine Vet J30(3), 220-234 PubMed.
  • Gabriel Aet al(1997)Morphometric study of the equine navicular bone, comparison between fore and rear limbs.Zentralbl Veterinarmed A44(9-10), 579-594 PubMed.
  • Dik K Jet al(1995)Role of navicular bone shape in the pathogenesis of navicular disease, a radiologic study.Equine Vet J27(5), 390-393 PubMed.
  • Hickman J (1989)Navicular disease - What are we talking about?Equine Vet J21(6), 395-398 PubMed.
  • Colles C (1982)Navicular disease and its treatment.In Practice4(2), 29-36 PubMed.

Other sources of information

  • Schneider R S, Gavin P R & Tucker R L (2003)What MRI is Teaching us about Navicular Disease.In:Proc 49th AAEP Convention.pp 210-219.


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