Research development involving large scale joint mechanics and biomechanical adaptations is growing. However, interest in smaller scale joints, such as the fingers, is limited. Thus, the present work describes the enhancement and clinical application of a previously designed in-vitro active finger motion simulator in measuring and assessing intrinsic joint kinematics and tissue biomechanics including load transfer and strains induced tissues within the finger. Accuracy of electromagnetic tracking (EM) systems were evaluated compared to the standard optical tracking systems and used to develop motion derived finger joint coordinate systems. Moreover, minute strain gauges were utilized to measure strains induced by the volar plate. Multiple in-vitro studies involving zone I and II injuries and repairs were evaluated where joint motion kinematics, tendon loads, work of flexion (WOF), and volar plate strains were measured. Strains, tendon load, and WOF increased with each progressive injury simulation. Joint kinematics were also significantly influenced with each injury simulation. Subsequent repair of the injuries restored metrics to the near-normal state. The active motion system and the present work advances the knowledge on finger biomechanics and provides researchers with a more detailed and refined insight on the overall effect of different innovate surgical techniques, rehabilitation protocols, and traumatic injuries on the biomechanics of single, or multiple, internal structures.