gms | German Medical Science

Objectives: Human allograft tendons are used in a variety of indications in the fields of sports medicine, foot and ankle as well as trauma surgery. In Germany, allograft sterilisation is still mandatory. While some sterilisation procedures affect tissue quality [1], peracetic acid (PAA) sterilisation is well-established and was shown to preserve tissue biomechanics of bone-patella tendon-bone constructs [2]. This study aims to evaluate the influence of PAA-sterilisation on the biomechanical properties of human tendons.

Methods: Pairs of tibialis anterior (TA) and posterior (TP) tendons were explanted and frozen according to tissue banking standards. For each pair, one tendon was sterilised in PAA leaving the contralateral tendon frozen. An a priori power analysis (β = 0.8) for paired comparisons revealed a necessary sample size of 9 in both groups. Tensile tests were performed on an InspektTableBlue (H&P, Germany). Samples were looped around bolts and cryoclamped on both ends while the midsubstance of the tendons remained free, adhering to material testing standards. Tendons received a 10-cycle preconditioning between 50 N and 250 N, a 5-minute load relaxation and a failure test with 50 mm/s speed.

Results and Conclusion: Out of 27 donors tested, tendons of nine pairs (TP: 5; TA:4) exhibited a valid failure mode of rupture at the midsubstance and hence were included in the analysis. There was no significant difference between PAA treated and fresh frozen (FF) TA and TP tendons in terms of failure load (PAA: 2557 ± 401 N vs. FF: 2394 ± 614 N). Additionally, both types of treatment revealed similar load relaxation behaviour (PAA: 17.0 ± 4.2 % vs. 18.4 ± 5.9 %).

PAA-sterilisation does not negatively influence biomechanical properties of human tendons in terms of relaxation and failure loads allowing for a safe and biomechanically reliable graft. The observed failure loads are comparable to the current literature.