Background: 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.
Hypothesis: A tubularized semitendinosus tendon will demonstrate a higher tensile load to failure and increased stiffness compared with its native form.
Study design: Controlled laboratory study.
Methods: 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.
Results: 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).
Conclusion: Tubularization of the semitendinosus graft weakens its structural and mechanical properties.
Clinical relevance: 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.