The Effects of a Crosslinked, Modified Hyaluronic Acid (xCMHA-S) Gel on Equine Tendon Healing.

This study investigates how applying a gel made from a special type of acid (xCMHA-S) during tendon surgery can help horses recover. Results indicate that the gel improves the natural healing process of tendons, leading to less visible damage and better recovery, compared to surgical procedures without the gel.

Study Design and Methods

• The research was conducted as an in vivo experimental study involving adult horses.
• A surgical procedure known as a full thickness bilateral forelimb window tenectomy was performed on both forelimb superficial digital flexor tendons of each horse. This surgery involves the removal of a section of tendon.
• During surgery, xCMHA-S gel was applied to the right forelimb’s tendon incision in all horses, while the left forelimb was left untreated, serving as the control for comparison.
• To monitor the healing process, the researchers conducted subsequent ultrasound examinations every 14 days over a span of 84 days.
• Tendon samples were carefully extracted after the horses were humanely euthanized at the end of the 84 day period for detailed analysis.

Results of the Study

• Results indicated that the use of xCMHA-S gel during surgery contributed to improved healing of the tendon.
• Ultrasound assessments revealed a significant drop in the average lesion size of treated tendons, which appeared unaffected at the end of study, compared to the control group which showed 30% lesions.
• Mean histologic tendon scores, which evaluate tissue and cellular change during healing, were notably lower in treated tendons, suggesting more advanced healing than in the untreated group.
• The treated tendons showed an increase in tendon cell density compared to untreated ones, and the signs of inflammation, new blood vessel formation, and variability in fiber diameter were also less pronounced in them.
• There were no notable differences in the shape of fibroblasts, levels of hemorrhage within the lesion, the alignment of collagen fibers, or in the diameter and disposition of collagen fibers between the treated and control groups.

Conclusions

• The study concluded that applying xCMHA-S gel during tendon surgery significantly aids the natural healing process.
• Enhancement was manifested in superior histologic healing scores and smaller sonographic lesions for the gel-treated tendons compared to their untreated counterparts.
• This suggests that xCMHA-S gel can be a beneficial addition to surgical procedures involving tendon damage and may significantly improve recovery outcomes.