Mechanical Properties of Patellar Tendon Allografts Subjected to Chemical Sterilization

Purpose: 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. Methods: 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. Results: 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). Conclusions: The preimplantation mechanical properties of BPTB allografts treated with BioCleanse are not significantly different from those of untreated controls. Clinical Relevance: 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.