Effect of preservation methods on tensile properties of human femur-ACL-tibial complex (FATC) - a cadaveric study on male subjects.

Purpose: Deep freezing and storing in formalin are some of the common techniques of human tissue preservation. However, the preservation modes affect the biomechanical properties of the tissues. In this work, the effects of the above-stated preservation tech- niques are compared with that of fresh cadaveric samples.

Methods: FATC samples from male cadavers of age between 60 and 70 years were tested under tensile loading at a strain rate of 0.8 s-1. Fourteen FATC samples from soft embalmed cadavers were preserved for 3 weeks by two methods: (a) 10% formalin and (b) deep freezing at -20 ° C followed by thawing. Seven FATC samples from fresh ca- davers were experimented as control samples. The results were evaluated by a two-stage statistical process of Kruskal-Wallis H test and Mann-Whitney U-test.

Results: It was observed that the failure force of fresh cadavers was the highest while that of preserved samples were approximately half the value. Failure elongation of frozen samples exceeded fresh samples while formalin samples failed at lesser elongations. Higher incidence of tibial insertion point or mid-section failures were observed in fresh samples while the higher incidence of ruptures at femoral insertion point was observed in the two preservation methods.

Conclusion: Tensile properties of fresh tissues vary significantly from that of formalin preserved or frozen preserved samples.