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NAV I CULAR D I SEASE
3
EQUINE MATTERS
Navicular
disease
Graham Hunter BVM&S GPCert(EqP) CertEP CertAVP(ESO) MRCVS,
Ardene House Vet Practice Ltd
Veterinary surgeon
Graham Hunter
XLEquine practice
Ardene House Vet
Practice Ltd
Wedges can be used to improve breakover
and reduction of compressive forces
Navicular disease is a poorly understood complex disease of the
horse’s feet. It strikes fear in the hearts of horse owners because
although our knowledge about this disease has improved, it can
still be a devastating and career limiting diagnosis. In the last few
decades with the application of advanced imaging techniques
our understanding of pathology in the horse’s foot has improved
to a level that we now understand this disease a lot better.
Previously when we only had x-rays to image
the navicular bone we were using the term
navicular disease to describe a huge number
of different pathological processes involving
many of the other structures of the navicular
(podotrochlear) apparatus. This led to the
evolution of the term ‘navicular syndrome‘ as
it was clear that it was not a single disease
and that many other structures were involved
in foot pain, and in particular in ‘heel pain‘.
With the use of advanced imaging such as
MRI even this term gets used less often as we
can more accurately describe the nature of
damage to individual structures.
Clinical presentation
Navicular disease can present in different
ways. It can be seen as slowly progressive
bilateral forelimb lameness or occasionally
as a severe unilateral lameness. Common
owner complaints would include a loss of
action or performance, an unwillingness to
jump, or an inability to lengthen the stride.
Lameness can also appear after a period of
forced rest. The onset of this condition is
usually seen in horses around 7 to 9 years
old but occasionally is seen in younger
horses. Navicular disease can also affect a
great variety of different breeds although it
is predominantly seen in Quarter Horses,
Warmbloods, and Thoroughbreds. It can also
be seen in a great variety of different foot
shapes from a flat-footed Thoroughbred to an
upright boxy foot of a Warmblood.
What causes navicular disease?
Historically, this disease was thought to be
caused by impaired or damaged blood
supply to the navicular bone resulting in
damage to the bone itself. This theory has
probably been largely disproven in favour
of a biomechanical theory. This idea
revolves round the concept that abnormal
compressive forces around the navicular
apparatus results in low grade cumulative
injuries or less commonly a one off sudden
traumatic injury. These abnormal forces
result in a variety of different injuries to the
navicular apparatus, which if not treated
early and correctly, triggers a degenerative
process that results in serious pathology to
the navicular bone and chronic lameness.
It has been shown that the shape of the
navicular bone, which is heritable can
predispose some horses to navicular disease.
Navicular disease can affect a variety of breeds,
although it is mainly seen in Quarter Horses
(above), Warmbloods and Thoroughbreds