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 and are mainly used in ACL reconstruction. 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 provide an overview of the biomechanical properties of different PAA-sterilised human tendon allografts.

Methods: The tendons, tibialis anterior (TA), posterior (TP), peroneus longus (PL), semitendinosus (ST) and gracilis (GR) underwent tensile testing. Tendons were all sterilised prior to testing. The parameters investigated were ultimate load and strength, stiffness, Young's modulus and relaxation. Biomechanical testing was 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: A similar ultimate load of up to 3000 N was observed for TA, TP and PL tendons. The force of these 3 tendon types was significantly higher than that of ST and GR tendons. The ultimate strength ranged from 60-200 MPa among tendon types. GR tendons had a significantly higher ultimate strength than TA/TP tendons while PL and ST tendons showed no difference from other tendon types. Here, GR tendons had the lowest stiffness compared with all other graft types. The Young's modulus testing displayed no significant differences between the groups. Relaxation testing documented that PL tendons showed similar relaxation to TA and TP tendons.

This study reports suitable tendon alternatives to be used in reconstructive surgery. This helps surgeons to identify the best graft choice for the patient's needs in line with the applied surgical procedure.