A comparison of structural and mechanical properties of tubularized and native semitendinosus graft.

Abstract

The semitendinosus tendon has a broad and thin length of aponeurosis. Tubularizing this portion of the graft converts it into a cylindrical structure, which may have implications for graft fixation. A tubularized semitendinosus tendon will demonstrate a higher tensile load to failure and increased stiffness compared with its native form. Controlled laboratory study. Twenty cadaveric paired semitendinosus specimens were used. Ten served as the control group; the other 10 underwent tubularization along the length of the aponeurosis. All testing was performed on the MTS 858 Mini Bionix II. Outcome measures included cross-sectional area, stress, stiffness, and peak load to failure. The nontubularized tendons had a higher peak tensile load to failure (mean 1112.6 +/- 345.0 N) than the tubularized tendons (mean 711.4 +/- 228.7 N, P = .007). The nontubularized specimens also had a higher stiffness (213.0 +/- 37.2 N) than the tabularized group (144.9 +/- 44.8 N, P = .002). Tubularization of the semitendinosus graft weakens its structural and mechanical properties. On the basis of the results of this study, we do not tubularize the semitendinosus graft in ACL reconstruction because of weakened structural and mechanical properties.