Role of navicular bone shape in the pathogenesis of navicular disease: a radiological study.

The research article examines if the shape of the navicular bone in horses, specifically Dutch Warmblood horses, can predispose them to navicular disease. The study found that the shape of the bone does seem to affect the incidence and type of disease, and also that this shape seems to be inherited from sire to progeny.

Selection and Study Design

• A set of 586 3-year-old female Dutch Warmblood horses were selected for this study. They were the progeny of 30 stallions
• Each group was designed to contain 20 animals for statistical reasons, presumably to maintain an adequate sample size for reliable results
• The researchers performed radiological examination of the front feet of both the stallions and their female offspring, using lateromedial and dorsopalmar upright pedal projections

Nature of the Findings

• The shape of the navicular bone was classified into one of four categories: concave, undulating, straight, or convex
• The condition of the navicular bone with respect to the disease was also graded on a scale of 0-4, with grades 3 and 4 reflecting more severe changes
• The study found a direct association between navicular bone shape and the severity of the disease

The Association of Shape With Disease

• Interestingly, the most severe disease occurred most often in those horses with convex-shaped, or “shape 4”, navicular bones
• The specific anatomical abnormalities differed between shapes 1 and 2 versus shape 3 – for shapes 1 and 2, the main abnormality was inverted flask-shaped channels, whereas for shape 3, the major problem was enthesiophytes
• These findings suggest that the bone shape predisposes the horse to variably severe forms of navicular disease

Hereditary Nature of Bone Shape

• The researchers also noticed that the shape of the navicular bone in the offspring closely matched that of the sire
• This finding indicates an hereditary component in the bone shape, thus genetic factors could potentially influence the predisposition to navicular disease in these animals

Conclusion

• This research presents significant findings in the understanding of navicular disease in horses
• The correlation between bone shape and susceptibility to the disease could potentially enable better prediction, prevention and treatment strategies for this condition