Functional treatment of acute rupture of the Achilles tendon. An experimental biomechanical study

In 84 adult rabbits the biomechanical properties of healing Achilles tendon rupture were examined 2, 4, 8 and 12 weeks (21 each group) after the injury. For the first time a mop-end-tear was performed. The following treatment modalities were applied (7 rabbits in each subgroup): (a) operative functional treatment (resorbable suture; Kleinert techniques); (b) operative functional treatment (fibrin glue); (c) primary functional treatment (conservative). The functional after treatment in all groups was performed with a specially developed orthesis, which was taped to the limb. For biomechanical testing a newly developed fixation technique (cryo-clamp) was applied, which guaranteed secure intratendineal rupture. After 2 weeks the fibrin glue-treated tendon ruptures showed the best results with regard to stiffness, tensile stress and max. rupture force. These results and a higher tensile stress of the sutured tendons were significantly different from those in the conservatively treated groups. After 4 weeks the stiffness in the fibrin group and the energy and rupture force in the suture group were significantly higher than in the group treated conservatively. The 8-week results revealed comparable biomechanical properties. The only significant difference was a higher energy in the fibrin glue group than in the conservative treatment group. The experiment revealed no significant biomechanical differences after 3 months. Compared with the results recorded for plaster immobilization in the literature, the functional treatment resulted in a significantly faster course of healing.