Influence of Temperature on the Biomechanical Stability of Titanium, PEEK, Poly-L-Lactic Acid, and β–Tricalcium Phosphate Poly-L-Lactic Acid Suture Anchors Tested on Human Humeri In Vitro in a Wet Environment

Abstract

The purpose of this study was to analyze the biomechanical integrity of suture anchors of different materials (titanium, PEEK [polyether ether ketone], poly-L-lactic acid [PLLA], and β-tricalcium phosphate PLLA) and almost identical design for rotator cuff repair in human humeri positioned in a water bath at room and body temperature undergoing cyclic loading rather than single-pull or static tests. Four different anchor models (n= 6) were tested using healthy human cadaveric humeri in a water bath thermostatically regulated at 20°C and 37°C. A cyclic testing protocol was used. The maximum failure load, the system displacement, and the respective mode of failure were recorded. There were no significant differences regarding the maximum failure load values between the 20°C groups and 37°C groups for the 4 different anchor materials. The displacement values for the 20°C groups and 37°C groups also were not statistically significant. Anchor and suture dislocations were the predominant modes of failure; suture ruptures were observed in few cases. This study shows that there are no significantly relevant differences regarding the maximum failure loads and the displacement values of the tested suture anchor systems in a wet environment at 20°C or 37°C. The temperature differences do not seem to affect the modes of failure either. Titanium, PEEK, PLLA, and β-tricalcium phosphate PLLA suture anchors for rotator cuff repair can be expected-on the basis of this investigation comparing laboratory temperature with body temperature and a wet environment-to perform invivo similar to invitro testing.