Muscle and tendon heating rates with therapeutic ultrasound in horses.

This study investigates the change in temperature in horse muscle and tendons during therapeutic ultrasound procedures and aims to establish guidelines for appropriate treatment methods. The results show that certain parameters of therapeutic ultrasound can adequately heat tendons, but not muscles, to a therapeutic temperature.

Objective and Methodology

• The objective was twofold – to measure the temperature change in the tendons and muscles of horses during therapeutic ultrasound, and based on the findings, develop guidelines for applying therapeutic ultrasound in cases of tendinous and muscular injuries in horses.
• The research involved an experimental study on 10 adult horses.
• Temperature sensors or thermistors were inserted into specific tendons – the superficial and deep digital flexor tendons (SDFT and DDFT), and at varying depths in the epaxial muscles.
• The left thoracic limb of each horse received a 10-minute therapeutic ultrasound treatment using a frequency of 3.3 MHz with an intensity of 1.0W/cm(2), while the right limb was treated at an intensity of 1.5 W/cm(2).
• The depth-specific muscle treatment lasted 20 minutes with a frequency of 3.3 MHz and intensity of 1.5 W/cm(2).
• The temperature was recorded before, during, and following each treatment. This data was then statistically analyzed.

Results

• By the end of the 1.0 W/cm(2) treatment, the mean temperature rise was 3.5°C in the SDFT and 2.5°C in the DDFT, while the 1.5-W/cm(2) treatment caused a greater temperature increase, with 5.2°C in the SDFT and 3.0°C in the DDFT.
• In the epaxial muscles, the temperature increases were not as significant, with only 1.3°C at a depth of 1.0 cm, and 0.7°C at depths of 4.0 cm and 8 cm.

Conclusions

• The findings indicate that when therapeutic ultrasound is applied at a frequency of 3.3 MHz and an intensity of 1.0 W/cm(2), the SDFT and DDFT are sufficiently heated to what is considered a therapeutic temperature.
• However, the same cannot be said about the epaxial muscles, which do not sufficiently heat up, even at the higher intensity of 1.5 W/cm(2).
• This research will help veterinary practitioners understand and apply the right ultrasound settings for the right type of tissue (muscles or tendons) in therapy settings for horses.