Foot and Ankle Surgery, vol.28, pp.1372-1376, 2022 (SCI-Expanded)
© 2022 European Foot and Ankle SocietyBackground: The current study aimed to compare biomechanical stability and healing process of side-to-side repair with overlapping repair after Achilles tendon lengthening with Z-plasty. Methods: In our study, 22 Sprague Dawley male rats were used. Side-to-side repairs were classified as group 1 and overlapping repairs as group 2. The left and right legs of seven rats were used to compare early group 1 and early group 2 biomechanical test results at day 0. Seven rats were used to compare late group 1 and late group 2 biomechanical test results at day 28. Both the right and left tendons were tested from the four rats examined in the biomechanically in the untreated control group. The last remaining four rats were used for histopathological evaluation of tendon repair, at 28-days from the index procedure.The ultimate load to failure was compared between groups. Results: At time 0, there were no measurable differences between group 1 (3.8 ± 1.4 N) and group 2 (3.7 ± 1.1 N), and both could endure less than one-tenth of the untreated control (49 ± 12). At 28 days, ultimate load to failure improved significantly in both group 1 (16.2 ± 3.5 N) and even more in group 2 (36 ± 8.1 N). While there was a significant difference between group 1 and group 2, neither were able to meet the untreated control (49 ± 12). Histopathological evaluation in the post-healing period showed that fibrosis, neovascularization, and inflammation increased in both groups. Conclusion: The overlapping suture technique and epitenon healing have more stability compared to side-to-side suture technique and endotenon healing. Human population trials may or may not exist, our study suggests it should be considered and further investigation needed before actual clinical application.