Equis ISSN 2398-2977

MCP/MTP joint: luxation

Contributor(s): Larry Booth, Jessica A Kidd-Millar, Graham Munroe, Vetstream Ltd, Chris Whitton

Introduction

  • Uncommon, lateral or medial luxation of metacarpophalangeal or metatarsophalangeal joint - occurs with rupture of medial or lateral collateral ligaments or an avulsion fracture.
  • Cause: usually associated with trapping distal limb in hole or cattlegrid, trailer/transport injury, or at high speed exercise.
  • Signs: lameness, angular deformity of distal limb, injury/trauma, excessive movement in fetlock joint.
  • Diagnosis: confirmed on radiography   Forelimb: radiography  - identifies any complicating bony injury. Ultrasound to assess collateral ligaments.
  • Treatment: reduction + cast immobilization   Musculoskeletal: external fixation - casts  usually achieves pasture soundness; open/compound luxations require more complex surgical techniques and more aggressive treatment. Occasionally the collateral ligament is repaired.
  • Prognosis: good for return to pasture/breeding soundness; open/compound luxations - guarded to poor.

Pathogenesis

Etiology

  • Trauma - distal limb trapped, eg hole or cattle grid, and animal attempting to remove its hoof.
  • Occasionally occurs during high speed activity involving increased rotational forces.

Pathophysiology

  • Luxation may be closed or open and occurs in association with rupture of the medial/lateral collateral ligament or an avulsion fracture.
  • Open luxations have the additional complication of probable joint sepsis and possible bone loss in trailer injuries from contact with the road.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Smith M R W (2010) Management of joint instability. Equine Vet Educ 22 (3), 112-114 Wiley Online Library.
  • Jalim S L, McKinnon A O & Russell T M (2009) Case report: Repair of a type IV Monteggia fracture in a foal. Aust Vet J 87(11), 463-466 PubMed.
  • Tenney W A & Whitcomb M B (2008) Rupture of collateral ligaments in metacarpophalangeal and metatarsophalangeal joints in horses: 17 cases (1999-2005). JAVMA 233 (3), 456-462 PubMed.
  • Balaam T M & Miller S (2007) Severe open metacarpophalangeal joint luxation in a mule foal. Equine Vet Educ 19 (10), 528-531 VetMedResource.
  • Yovich J V, Turner A S, Stashak T S and McIlwraith C W (1987) Luxation of metacarpophalangeal and metatarsophalangeal joints in horses. Equine Vet J 19, 295-298 PubMed.


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