[Scanning electron microscopic findings of the navicular bone and deep flexor tendon in podotrochlosis of horses].

The research studies the microscopic findings on the navicular bone and the deep flexor tendon in horses suffering from podotrochlosis. The study has found significant damage in the navicular bone and opposite surface of the deep flexor tendon in horses with the condition, suggesting the changes caused by repeated minor trauma start at the surface of the deep flexor tendon and subsequently spread to the opposing section of the navicular bone.

Methodology

• The study examined the podotrochlea (part of the horse’s hoof complex) of 49 forelimbs of 25 adult horses using both light and electron microscopy.
• The horses were divided into three groups based on their clinical diagnosis: horses with lameness due to podotrochlosis (group 1), horses with lameness due to tendopathy (group 2), and horses without lameness (group 3).

Findings

• The most impactfulg pathological findings were noted in horses from group 1 (those with podotrochlosis) – these included loss of cartilage and tendon matrix, exposure of collagen fibrils, superficial degeneration and necrosis, occasional presence of fissures and significant defects, sometimes accompanied by adhesions between the tendon and navicular bone surface.
• Even in tendons and navicular bones that appeared slightly altered according to radiological tests, light and scanning electron microscopy often revealed moderate to severe pathological changes. These changes could occasionally also be found in clinically healthy horses (group 3).

Conclusions

• The distribution of the lesions indicates that initial alterations caused by repeated minor injuries start at the surface of the deep flexor tendon and subsequently spread to the facies flexoria (opposing section) of the navicular bone in the course of podotrochlosis.
• It was noted that the involvement of the cartilage and the synovial layer (lining of the joint) of the hoof joint in cases with podotrochlosis was rarely observed and is considered to be a secondary manifestation or a consequence of the primary disease.