Comparison of tenoscopic and ultrasonographic methods of examination of the digital flexor tendon sheath in horses.

The research compares the effectiveness and limitations of using ultrasonography (sonographic findings) and tenoscopy (tenoscopic findings) in diagnosing injuries or abnormalities in horses’ digital flexor tendon sheath (DFTS). The study was performed on 22 horses and established that while ultrasonography is a useful non-invasive diagnostic method, it does have its limitations and is not always wholly reliable.

Methodology

• The researchers compared the results of ultrasonographic and tenoscopic examinations of the digital flexor tendon sheath (DFTS), the palmar/plantar annular ligament (PAL), and the superficial and deep digital flexor tendons (SDFT and DDFT) in a sample of 22 horses.
• The horses used in the study had previously undergone a procedure known as tenoscopic desmotomy of the palmar/plantar annular ligament. The medical records of these horses were retrospectively examined for the study.

Findings

• The study found that ultrasonography had a fairly high sensitivity (90.9%) in diagnosing abnormalities within the DFTS when these findings were verified by tenoscopy. However, the specificity of ultrasonography was lower (53.8%), indicating a less reliable ability to rule out abnormalities when they are actually absent.
• The sensitivity and specificity of sonographic examination at the PAL were 68.8% and 50% respectively. The positive predictive value, which measures the probability of correctly identifying a positive result, was 73.3%.
• When examining the SDFT and DDFT tendons, ultrasonography proved less successful. Of 12 abnormal findings in the SDF tendons revealed through ultrasonography, only six were confirmed through tenoscopy. Furthermore, sonography failed to identify any abnormalities in seven deep digital flexor tendons that were tenoscopically detected.
• In terms of locating lesions on the DDFT, ultrasonography had a low sensitivity rate (36.4%). This shows that ultrasonography was not successful in detecting most of the abnormalities when compared to tenoscopy.

Implications

• These results underscore the importance of considering the limitations of ultrasonographic examinations. While ultrasonography is a non-invasive and relatively easy method of examination, its lower specificity and sensitivity in certain areas suggests it should not be the only tool used for diagnosing tendon injuries or abnormalities in horses.
• Especially when detectable echogenic materials are observed, which can affect ultrasound results, there should be caution in interpretation. The tendency of ultrasonography to provide false positives or miss certain abnormalities suggests that it may need to be supplemented or validated by other methods, such as tenoscopy.