Calcitonin effect on Achilles tendon healing. An experimental study on rabbits

Objective: A positive potential effect of Calcitonin (CT) on Achilles tendon healing was investigated as well as the ability of MRI to follow the tendon healing process. Materials and Methods: A standardized tenotomy of the Achilles tendon was performed on forty-two rabbits. Twenty-one animals received daily 21 IU/kg Calcitonin intramuscularly (treatment group CT) during the experiment and the remaining received saline solution (control group P). Seven animals from each group were killed at one, two and three weeks postoperatively. All animals had serial MRI scans and tendon samples underwent biomechanical and histological testing. Results: For both groups, animals of the same subgroup showed statistically significant difference in signal intensity values of MRI between the 1(st) and 3(rd) week (p<0.001) and between the 2(nd) and 3(rd) week (p< 0.001). Signal intensity values of MRI didn't show any differences between animals under treatment and controls measured at 1(st) (p=0.23), 2(nd) (p=0.23) and 3(rd) (p=0.53) postoperative week. Tendon samples from group CT showed statistically significant difference in ultimate tensile strength compared to controls at 2 (p<0,0005) and 3 (p< 0,0005) weeks post-surgery. Histology showed a positive Calcitonin effect at all tendon healing stages. Conclusion: It is suggested that Calcitonin enhances Achilles tendon healing process.