Pressure distribution between the deep digital flexor tendon and the navicular bone, and the effect of raising the heels in vitro

M.P. Weaver; D.J. Shaw; G. Munaiwa; D.P. FitzPatrick; C.R. Bellenger

doi:10.3415/VCOT-08-05-0043

Veterinary and Comparative Orthopaedics and Traumatology, Table of Contents

Vet Comp Orthop Traumatol 2009; 22(04): 278-282
DOI: 10.3415/VCOT-08-05-0043

Original Research

Schattauer GmbH

Pressure distribution between the deep digital flexor tendon and the navicular bone, and the effect of raising the heels in vitro

M.P. Weaver

¹University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian, UK

,

D.J. Shaw

²Royal (Dick) School of Veterinary Medicine, University of Edinburgh, Roslin, UK

,

G. Munaiwa

³University College Dublin, School of Agriculture, Food Science and Veterinary Medicine, Belfield, Dublin, Ireland

,

D.P. FitzPatrick

⁴ University College Dublin, School of Electrical, Electronic and Mechanical Engineering, Belfield, Dublin, Ireland

,

C.R. Bellenger

³University College Dublin, School of Agriculture, Food Science and Veterinary Medicine, Belfield, Dublin, Ireland

› Author Affiliations

Abstract

Summary

The objectives of this study were to topo-graphically map pressure distribution across the palmar surface of the navicular bone in response to forces applied by the deep digital flexor tendon (DDFT), and evaluate the effect of raising the heels in vitro. A rig was constructed to hold an equine cadaver limb and apply controlled pressure to the navicular bone from the DDFT. Pressure-sensitive paper was used to quantify and map the resultant pressure. Changes in response to heel wedges (5° and 10°) were recorded. The areas subject to maximum pressure from the DDFT were: the central ridge, the paired symmetrical areas adjacent to the ridge and the distal edge of the palmar bone surface. These regions correspond to the known sites of navicular pathology. Heel wedges redistributed the pressure exerted on the palmar surface of the navicular bone, with measurements varying depending on fetlock angle and wedge angle. These in vitro results support the hypothesis that inappropriate forces exerted via the DDFT on the bone cause navicular disease. However, they throw doubt on the practice of shoeing such horses with heel wedges as the redistribution of pressure may increase the force exerted on regions predisposed to disease.

Keywords

Navicular bone - pressure - horse - heel wedges

Full Text

References

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