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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