Grant: Discovery Grants Program - Individual

Unlike the multitude of biomechanical testing approaches that have been developed for the hip, knee, and spine over the past three decades, shoulder testing systems are relatively few and in their infancy. Experimental shoulder devices typically employ static loading protocols on cadaver specimens to produce isometric (i.e. stationary) testing. Some recent systems have produced arm motion using simplified muscle controlling protocols and/or robotics. However, these approaches do not fully reproduce muscle loading across the joint or achieve adequate velocity control. Moreover, common maneuvers such as arm elevation involve rotation of both the ball and socket (glenohumeral) joint, and the shoulder blade to trunk (scapulothoracic) articulation. These two motions have not been well established in the experimental setting. It is logical to postulate that optimizing our understanding and evaluation of this joint necessitates the development and application of advanced comprehensive testing approaches. Hence, this discovery proposal will focus on the development and application of novel shoulder-testing systems and measurement techniques for experimental biomechanical investigations of the shoulder. These developments are an important precursor to a more complete understanding of the biomechanics of this joint. Further, implant development and reconstruction relies heavily on extensive biomechanical testing and analyses. This is especially true of new ?reverse? prosthesis where the head and socket are reversed to provide a mechanical advantage during arm elevation. While these are rapidly growing in popularity, better testing approaches are needed to more fully comprehend their mechanical performance. The long-term objective of this research is to elucidate the biomechanics of the shoulder and provide a robust and comprehensive approach to its evaluation. The short-term overall objective of this proposal is to develop and employ advanced shoulder-testing systems and analysis techniques to investigate the biomechanics of the shoulder for abduction (arm elevation) motion, with special interest in implant testing. The two specific objectives are: 1) To comprehend the biomechanics of the shoulder using an in-vitro testing simulator capable of both glenohumeral and scapulothoracic motion. 2) To establish how shoulder implant design and positioning affects joint loading using a specially designed instrumented implant system. The work proposed herein will lead to new discoveries related to the understanding of the biomechanics of the shoulder. These developments will also result in the evolution of a state of the art testing program that will permit a wide range of advanced research-based studies on the shoulder. Furthermore, the detailed investigations proposed will yield important results and findings that will contribute to improving testing approaches and computational models by my group and others. Ultimately, completion of this 5-year plan will very likely ensure that our laboratory will continue to excel in research of this nature, and be a world leader for the biomechanical assessment of the shoulder, with special expertise in comprehensive approaches to experimental testing and modelling.