Equis ISSN 2398-2977

Proximal phalanx: fracture

Synonym(s): Split pastern

Contributor(s): Steve Adair, Vetstream Ltd, Chris Whitton

Introduction

Pathogenesis

Etiology

  • Performance horses   →   repetitive concussive forces   →   fatigue fracture.
  • Stepped on by dam.
  • Pasture accident.

Specific

Pathophysiology

  • Chip fractures:
    • Racing and other performance horses.
    • Intra-articular fracture.
  • Major fractures:
    • Mid-sagittal groove of proximal joint surface   →   distally.
    • Compressive and torsional forces.
    • Forelimb > hindlimb.
    • More commonly a racing injury, but can occur at pasture.
    • Unfused fragment   →   palmar or plantar wing fractures (young horses).
    • Medial collateral ligament avulsion fractures (young horses).
    • Dorsal frontal (high speed injury) and dorsal (low impact injury) fractures: Deceleration of the metacarpus/metatarsus against the proximal phalanx while the metacarpo/metatarsophalangeal joint is extended or slightly flexed.
    • Short sagittal fractures - about 1 cm long; in hindlimb subjected to more stress on rising from ground   →   displacement more likely.
    • Comminuted fractures.
  • Severely comminuted fractures - release of substantial internal energy   →   multiple fragmentation of the phalanx.

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 & Wright I M (2014) Are there radiologically identifiable prodromal changes in Thoroughbred racehorses with parasagittal fractures of the proximal phalanx? Equine Vet J 46 (1), 88-91 PubMed.
  • Smith M R W & Wright I M (2014) Radiographic configuration and healing of 121 fractures of the proximal in 120 Thoroughbred racehorses (2007-2011). Equine Vet J 46 (1), 81-87 PubMed.
  • Ramzan P H L & Powell S E (2010) Clinical and imaging features of suspected prodromal fracture of the proximal phalanx in three Thoroughbred racehorses. Equine Vet J 42 (2), 164-169 PubMed.
  • Cullimore A M, Finnie J W, Marmion W J & Booth T M (2009) Severe lameness associated with an impact fracture of the proximal phalanx in a filly. Equine Vet Educ 21 (5), 247-251 VetMedResource.
  • Dechant J E et al (1998) Repair of complete dorsal fracture of the proximal phalanx in two horses. Vet Surg 27 (5), 445-449 (description of fracture type, and management) PubMed
  • Tetens J et al (1997) Comparison of racing performance before and after treatment of incomplete, midsagittal fractures of the proximal phalanx in Standardbreds - 49 cases (1986-1992). JAVMA 210 (1), 82-86 PubMed.
  • Holcombe S J et al (1995) Lag screw fixation of noncomminuted sagittal fractures of the proximal phalanx in racehorses - 59 cases (1973-1991). JAVMA 206 (8), 1195-1199 PubMed.
  • McClure S R et al (1995) Managing equine fractures with external skeletal fixation. Comp Contin Educ Pract Vet 17, 1054-1063 VetMedResource.
  • Nemeth F et al (1991) The use of the walking cast to repair fractures in horses and ponies. Equine Vet J 23, 32-36 PubMed.
  • Ellis D R et al (1987) Observations and management of fractures of the proximal phalanx in young Thoroughbreds. Equine Vet J 19 (1), 43-49 PubMed.
  • Nunamaker D M et al (1986) A new external skeletal fixation device that allows immediate full weightbearing application in the horse. Vet Surg 15, 345-355 VetMedResource.
  • Bukowiecki C F et al (1986) Palmar/plantar process fractures of the proximal phalanx in 15 horses. Vet Surg 15, 383-388 VetMedResource.
  • Markel M D et al (1985) Noncomminuted fractures of the proximal phalanx in 69 horses. JAVMA 186 (6), 573-597 PubMed.

Other sources of information

  • Richardson D W (1996) Fractures of the proximal phalanx. In: Equine Fracture Repair. Ed: Nixon A J. W B Saunders, USA.


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