The effect of freeze-dried human amnion on New Zealand rabbit tendon healing

Background: Hand injury often causes acute morbidity and long-term disability. In the case of hand surgery, thirty percent of cases are from tendon injuries. The biomechanical strength of the tendon plays an important role in preventing post-repair rupture, where this strength is believed to be influenced by the number of strands of thread or the suturing technique used. In addition, biological materials such as amnion can reduce the risk of tendon adhesions and increase the biomechanical strength of the tendon itself. Method: This study used an experimental randomized post-test-only control group research design. 18 male New Zealand rabbits had their right Achilles tendon severed, then divided into 2 groups, where group A was treated as a control while group B was treated with freeze-dried human amnion after tendon repair using braided suture (silk) material. On day 21, all rabbits were terminated and subjected to the macroscopic examination of tensile strength and microscopic examination of the number of fibroblasts and collagen density with hematoxylin-eosin staining. The test that will be carried out on each variable is the Mann-Whitney Test and T-test methods. Result: The results showed that the average tensile strength in the treatment group was significantly greater than the control group (3.02±1.05 N/mm2 vs. 0.78±0.28 N/mm2, p<0.05). The mean number of fibroblasts in the treatment group was significantly greater than the control group (189.67±23.34 vs. 85.44±9.17, p<0.05). For the variable collagen density, 77.80% of the treatment group had collagen density with a score of 3 (p<0.05). Conclusion: The application of freeze-dried human amnion after tendon grafting using braided suture material could increase tensile strength, number of fibroblasts, and collagen density in tendon healing.