Ultrasonographic and histopathological findings in equine superficial digital flexor tendon injury.

This study compares the ultrasonographic and histopathological findings in healthy and injured equine superficial digital flexor tendons, showcasing the relationship between both aspects and how they can be used for accurate injury assessment.

Study Overview

• The research involved the analysis of 12 normal and 28 injured superficial digital flexor tendons in horses. The injuries ranged in duration from 2 days to 15 months.
• The goal was to compare ultrasonographic findings (images of the tendon obtained using ultrasound) with histopathological findings (microscopic examination of the tissue).

Key Findings

• There was a consistent correlation found between the two methods of examination, enabling the researchers to make accurate assessments about the nature and timeline of the injury.
• Various characteristics from the ultrasound images such as echogenicity of lesions, how distinctly they could be differentiated from the surrounding tissue, and the presence and arrangement of the linear echoes were used to interpret the findings.

Observations Based on Injury Age

• Acute injury or new injuries were characterised by an absence of shadow (anechoic), a mix of anechoic and hypoechoic (less bright) areas or diffused hypoechoic appearance. This indicated bleeding, fibrolysis (breaking down of fibrous tissue), and the formation of early granulation tissue (new connective tissue and microscopic blood vessels that form on the surfaces of a wound).
• Fibroplasia (the process of forming new fibrous tissue) and mature granulation tissue were linked with well to moderately well defined hypoechoic lesions.
• Chronic fibrosis (long term damage resulting in the formation of excess fibrous connective tissue), was found to be characterised by heterogeneously echogenic areas which were poorly defined from the surrounding tissue and had irregularly arranged linear echoes on longitudinal images.

Concluding Remarks

• Scarring within the tendon resulted in multiple bright spots (hyperechoic foci) in the ultrasound imaging.
• Extensive damage wrapping around the tendon (peritendinous lesions) was easy to identify on ultrasound scans. However, adhesions between tendons (intertendinous adhesions) were challenging to assess due to poorly defined borders between the superficial and deep digital flexor tendons.

In conclusion, the research underlines the value of comparing ultrasonographic and histopathological examination results in assessing the age and severity of tendon injuries in horses.