GAIT BIOMECHANICS OF RABBITS WITH EITHER ACHILLES OR TIBIALIS CRANIALIS ARTIFICIAL TENDONS

Abstract

Artificial tendons have been developed as a replacement for biological tendons with irreparable pathologies and defects. Previous studies reported the mechanical strength and tissue integration of a polyester suture-based artificial tendon, but not its effect on locomotor function. The objective of this study was to quantify the hindlimb biomechanics during hopping gait of New Zealand White rabbits with surgical replacement of either the Achilles (n=2) or tibialis cranialis (TC, n=2) biological tendons with artificial tendons. Once pre-surgery and for five consecutive weeks post-surgery (starting at about two weeks post-surgery), we measured hindlimb kinematics and ground contact pressures with a video camera and pressure mat, respectively. Promisingly, post-surgical locomotor function was either consistent or improved over time in both tendon replacement groups. However, Achilles rabbits exhibited greater immediate post-surgery functional decline and less post-surgical functional recovery than TC rabbits. Compared to healthy rabbits, at the study endpoint, (1) TC rabbits had a 17.3-degree higher (i.e., more plantarflexed) ankle angle at foot strike; and (2) Achilles rabbits had a 39.2-degree lower (i.e., more dorsiflexed) ankle angle at toe off. These functional deficits suggest that the muscles attached to the artificial tendons had lower force-generating capacity. Future studies of artificial tendons are needed to quantify long-term function, determine the effectiveness of structured rehabilitation exercises, and refine surgical implementation.