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

Abstract

Summary From progeny lists of 30 Dutch Warmblood sires, 586 3‐year‐old females by these stallions were randomly selected, each progeny group aimed at 20 animals for statistical reasons. The front feet of the sires and female progeny were examined radiographically using lateromedial and dorsopalmar upright pedal projections. The radiological features associated with navicular disease were classified 0–4 using a standardised classification, grades 3 and 4 representing the more severe changes. The shape of the proximal articular border of the navicular bone outlined on the dorsopalmar view was classified 1–4: l=concave; 2=undulating; 3=straight; 4=convex. A significant shape‐grade association was found, the highest grades 3 and 4 incidence associated with shape 1 and the lowest grades 3 and 4 incidence demonstrated by shape 4. In shapes 1 and 2, navicular bones grades 3 and 4 features were mainly characterised by inverted flask‐shaped channels. In shape 3, navicular bones grades 3 and 4 were dominated by enthesiophytes. These findings indicate an apparent shape predisposition to radiological changes associated with navicular disease. The shape of the navicular bone in the offspring was on average the same as the sire, indicating an hereditary element in navicular bone shape.

Radiological interpretation of the navicular bone

“…The proximal articular border may be convex, horizontal or undulating or concave as seen in a DPr-PaDiO view (Fig 6). In Dutch Warmblood horses it has been suggested that horses with a convex or horizontal proximal articular border are at less risk of navicular disease compared with those with an undulating or concave articular margin (Dik and Broek 1995;Dik et al 2001a,b). Similar studies have not been performed in other breeds to verify these observations.…”

Avaliação radiográfica e ultrassonográfica do aparato podotroclear de cavalos Quarto de Milha diagnosticados com síndrome do navicular

“…Os resultados do estudo sugerem que a formação do tipo de lesões radiográfi-cas no osso sesamóideo distal dos equinos avaliados pode ter correlação com tipo de atividade esportiva que esses equinos desempenham, concordando com a suspeita de Wintzer (1990). Observou-se também diferença na arquitetura ou forma anatômica do bordo proximal do osso sesamóide distal dos equinos avaliados nesse experimento com síndrome do navicular como afirmam Dik & Van Den Broek (1995) e Rijkenhuizen (2006). Ruohoniemi et al (1998), Dik et al (2001) e Rijkenhuizen (2006) descrevem que o formato do bordo proximal é geneticamente determinado e podem contribuir como fator predisponente para o desenvolvimento da síndro-me do navicular.…”

Relationships of age and shape of the navicular bone to the development of navicular disease: a radiological study

“…The radiographic examination of all horses was performed at the Department of Radiology, Faculty of Veterinary Medicine, University of Utrecht. The examination always included lateromedial and dorsoproximal-palmarodistal oblique (upright pedal) projections of both forefeet, using the same technique as described for the initial study on the role of the shape of the navicular bone (Dik and van den Broek 1995).…”

“…The association between the radiological and clinical features of this syndrome is controversial. However, the use of a standardised classification system of the radiographic findings, which includes all these features (Dik 1992;Dik and van den Broek 1995), enables the quantitative comparison of the navicular bone pathology of different horses. In this system, grades 0 and 1 reflect the normal navicular bone, grade 2 stands for a fair radiological condition, and grades 3 and 4 for the more severe radiological conditions.…”

“…On dorsoproximal-palmarodistal oblique (upright pedal) radiographs the proximal contour of the flexor cortex of the navicular bone is usually convex, but the proximal articular border may be concave (shape 1), undulating (shape 2), straight (shape 3) or convex (shape 4). In the Dutch Warmblood this variation in shape has been found to be genetically determined and appears to be one of the conformational determinants of the susceptibility for the development of navicular disease, probably due to a shape dependent distribution of the biomechanical forces exerted on the bone (Dik and van den Broek 1995).…”