Canis ISSN: 2398-2942

Osteochondrosis

Synonym(s): OCD

Contributor(s): Joseph Harari

Introduction

  • Abnormal development/differentiation of growth cartilage in both physis and epiphysis.
  • Primarily cartilage lesion, although term implies changes in both bone and cartilage.
  • Cause: failure of endochondral ossification.
  • Signs: lameness.
  • Diagnosis: signs, signalment, radiography.
  • Treatment: may be limiting. Usually surgical excision of affected cartilage.
  • Prognosis: varies with joint affected but often → osteoarthrosis.

Pathogenesis

Etiology

  • Failure of chondrocytes to mature.

Factors influencing growth rate and endochondral ossification

  • Diet: in young animals (especially if fed ad-lib). Various combinations of:
    • High energy (primarily).
    • High protein (less critical).
    • Excessive calcium (less critical).
    • Phosphorus (less critical).
    • Vitamin D (less critical).
  • Heredity: unknown significance, although condition seen primarily in large breeds.
  • Endocrine: somatropin and thyrotropin have been implicated. Greater incidence in males which may grow faster.

Other factors

  • Micro-trauma: may be significant. Site of lesion in individual joint is related to weight-bearing distribution in that joint. Inability of diseased cartilage to withstand normal trauma.

Predisposing factors

General

  • Fast growth.

Pathophysiology

  • Areas of necrosis in cartilage.
  • Cartilage thickened due to accumulation of transitional chondrocytes with failure of vascular penetration.
  • Endochondral ossification does not take place. Horizontal clefts exist between normal cartilage and abnormal vertical clefts break through to surface → flaps.
  • OCD flaps separate along normal/abnormal junction → may become detached → nourished by synovial fluid → grow and calcify.
  • Joint mice may become trapped → lameness.

Timecourse

  • Weeks to months.

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.
  • Morgan J P, Wind A & Davidson A P (1999) Bone dysplasias in the labrador retriever - radiographic study. JAAHA 35 (4), 332-340 PubMed.
  • Harari J (1998) Osteochondrosis. Vet Clin North Am Small Anim Pract 28 (1), 1-195 VetMedResource.


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