In vivo comparison of biomechanical, histological, and radiological properties of three techniques for tendon lengthening: an experimental study in rabbits.

Biomechanical, histological, and radiological properties of three different techniques of tendon lengthening - Z-plasty, modified Vulpius, and modified Baker - were investigated and compared. Sixty white female Angora rabbits (mean weight 4.1 kg, range 3.9 kg- 4.2 kg) were randomly divided into three groups: Z-plasty, V-Y plasty (modified Vulpius technique), and U-T plasty (modified Baker technique). Histopathological, radiological, and biomechanical properties were evaluated at the third and sixth postoperative week. Qualitative analysis of ultrasound examination showed that Z-plasty had the most irregular echo pattern at the third postoperative week, and had less echogenic areas at the sixth postoperative week. Histological evaluation showed that Z-plasty had significantly more formation of fibrosis and adhesion and less parallel homogeneous collagen fibres at the sixth postoperative week (p<0.05). U-T plasty had a significantly higher mean (SD) failure load (15.35 (1.89) N) than the other two methods during the third postoperative week (p<0.05). There was no significant difference in failure load between the groups at the sixth postoperative week. U-T plasty is a good alternative to Z-plasty technique for lengthening tendons, and it may be the first choice in those who need moderate lengthening of tendons and early rehabilitation because it is easy to do, heals better, and has good biomechanical properties.