Mechanical properties of patellar tendon allografts subjected to chemical sterilization.

Abstract

We tested the hypothesis that the preimplantation mechanical properties of BioCleanse-treated bone-patellar tendon-bone (BPTB) allografts are not significantly different from those of untreated specimens. For this controlled laboratory study, specimens were harvested as central third or hemi-BPTB units from both knees of 17 cadaveric tissue donors (11 men and 6 women) aged 19 to 88 years. Donor-matched specimens (20 per group) were randomly assigned to either BioCleanse-treated or untreated control groups. Specimens were subjected to 25 minutes of pretensioning at 89 N and then cyclically loaded under longitudinal tension between 50 N and 250 N for 1,000 cycles at 1 Hz, followed by ramp to failure at 50 mm/min. No statistically significant difference was found between untreated and BioCleanse-treated specimens in stiffness (235.3 +/- 37.6 N/mm v 222.3 +/- 53.4 N/mm, P = .37), cyclic creep (0.38 +/- 0.42 mm v 0.40 +/- 0.26 mm, P = .81), maximum force (1,685.7 +/- 471.6 N v 1,807.0 +/- 657.8 N, P = .47), or ultimate stress (29.0 +/- 9.8 MPa v 29.0 +/- 12.8 MPa, P = .98). The preimplantation mechanical properties of BPTB allografts treated with BioCleanse are not significantly different from those of untreated controls. This laboratory study compares the biomechanical properties of chemically treated allografts, which are currently being used in anterior cruciate ligament reconstruction, with those of nontreated fresh-frozen allografts.