Achilles tendon regeneration after experimental transverse tenotomy with preserved peritenon and the structures

Abstract

Introduction The Ponseti method is the first choice for congenital clubfoot with the possibilities of transverse tenotomy being underexplored in repair of the Achilles tendon in pediatric patients.The objective was to identify specific features of the Achilles tendon repair after experimental transverse intersection and preserved peritenon, vessels and nerves of growing rabbits.Material and methods The experimental study included 20 Chinchilla rabbits of both sexes aged 1.0–1.5 months used as a biomodel with a weight of 1476.0 ± 114.3 g. Rabbits were sacrificed in groups of five by air embolism under local anesthesia at 15, 30, 60 and 90 days of surgery.Results The tendon defect zone was represented by small areas of dense fibrous scar tissue with some cellular fibroblasts, and tendon fibers of unremarkable architectonics arranged in a mutually parallel waves could be seen in the layers of connective tissue at 90 days. The thickness of the first-order collagen fibers increased to 8.9 ± 1.32 µm and comparison with the normal value of 9.2 ± 1.88 µm showed no statistically significant difference (p = 0.38). The thickness of the second-order collagen fibers increased to 28.1 ± 1.28 µm during the time, and comparison with the standard measurements of 28.3 ± 2.23 µm demonstrated no statistically significant difference (p = 0.64).Discussion According to the literature, the ability of the tenoblast to synthesize structural proteins and regulatory biomolecules after injury decreases with age and leads to fibrous restoration of the tendon and formation of a permanent scar. Our study on growing rabbits showed that the organotypic structure of the experimental tendon restored at the intersection site at 60 days with the Achilles tendon defect being represented by the tendon-like tissue at 90 days.Conclusion The Achilles tendon was shown to regenerate in optimal conditions after the dissection and preservation of the peritenon, vessels and nerves with tendon tissue being formed within a short time (3 months after the intervention) being identical to the original.