Pathophysiology and diagnosis of third carpal bone disease in horses: a review.

This research article delves into third carpal bone disease, a common cause of lameness in some horse breeds. The authors discuss how changes in the bone’s density due to exercise could lead to injuries, examine existing diagnostic methods, and consider potential improvements.

Understanding Third Carpal Bone Disease

• The third carpal bone (C3) disease in horses, particularly among Standardbred and Thoroughbred breeds, is a primary factor contributing to lameness. This condition is characterized by an increased bone density of C3 brought on by physical exertion.
• Increased bone density reduces the elasticity of the bone, hence making it more inclined towards injuries. This interplay between physical activity and susceptibility to C3 disease is at the core of the research.

Diagnosis and Detection Methods

• Currently, the principal method of diagnosing this disease is subjective radiography using a tangential view. Through radiographic means, increased bone mineral density (BMD) appears as sclerosis (hardening of tissue).
• However, the onset of disease or an elevated risk of C3 fracture as indicated by an increase in sclerosis is yet to be known. Therefore, a deeper investigation into the bone’s BMD can enhance our understanding of the changes that occur in the horse’s C3 and aid in improved athletic management. The presumption is that changes in BMD surface before any damage to articular cartilage, which is vital in joint movement.
• To detect osteoporosis in humans, non-invasive bone-mineral analysis techniques like single photon absorptiometry (SPA), dual x-ray absorptiometry (DXA), computed tomography (CT), radioabsorptiometry (RA), quantitative ultrasonography (QU), and magnetic resonance imaging (MRI) are used. In horses, DXA and RA are the most common methods for the same.

Challenges and Opportunities

• Despite DXA’s prevalence in bone-mineral analysis, the associated high costs and operational challenges in live animals limit its routine use for diagnostic purposes.
• RA shows promise for applicability in C3 analysis in horses. However, there is a significant issue with this method: minor variations in the x-ray beam angle during the tangential view can drastically alter the results, rendering this technique clinically non-applicable at present.
• As a conclusion, the researchers emphasize that the current methods of quantitative non-invasive bone-mineral analysis in diagnosing C3 disease in horses are unsuitable for clinical application. Suggesting, therefore, a gap exists for solutions that can provide a clinically effective, non-invasive approach for early C3 disease detection, thus promoting better horse health management.