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In partial fulfillment of the Requirements for the Degree of
Doctor of Philosophy in Applied Physiology
in the
School of Biological Sciences
Joshua R. Jarrell
will defend his thesis
Quadrupedal locomotion with a unilateral bone-anchored transtibial prosthesis in the cat
Thursday, August 31, 2017
9:00am
Auditorium, room 1253
555 Fourteenth Street
Thesis Advisor
Boris I. Prilutsky, Ph.D. (Advisor)
Committee Members
T. Richard Nichols, Ph.D.
Johnna S. Temenoff, Ph.D.
Young-Hui Chang, Ph.D.
W. Lee Childers, Ph.D.
Abstract
Bone-anchored limb prostheses offer numerous advantages over conventional socket-supported prostheses. As opposed to socket prostheses, loads on a bone-anchored prosthetic limb during natural activities are directly transmitted to the residual bone, which prevents damage of skin and other soft tissues. Despite this and other documented advantages, however, bone-anchored prostheses have been limited in their availability in the United States due to an increased risk of skin and deep tissue infection through the skin-implant interface. A novel porous titanium pylon, the skin- and bone-integrating pylon (SBIP), has been developed to promote deeper tissue integration with the percutaneous implant and thereby reduce the risk of infection (Pitkin et al., 2009; Pitkin and Raykhtsaum, 2012; Farrell et al., 2014). Further research is needed to examine if the SBIP can be utilized for anchoring a limb prosthesis in natural load bearing applications. In veterinary medicine, gait changes in animals after limb loss and subsequent prosthesis intervention have not been extensively investigated. In addition, it is not completely understood how the motor system adapts to a loss of sensory feedback from the distal leg and to a reduced ability to absorb and generate mechanical energy for locomotion. Currently, detailed biomechanical analyses of such adaptations are missing. Therefore, the overall goal of my research was to investigate the effects of walking with a unilateral, transtibial, bone-anchored via SBIP prosthesis on mechanics and stability of quadrupedal locomotion and on tissue integration with the SBIP implant. The general hypothesis tested was that the SBIP would provide secure, infection free anchoring of a transtibial prosthesis and that would permit the cats to adopt the prosthesis for stable quadrupedal locomotion. In Specific Aim 1, I examined the ability of the SBIP to serve as attachment for a unilateral, transtibial bone-anchored prosthesis during walking in the cat. In Specific Aim 2, I investigated dynamic stability by analyzing margins of dynamic stability and changes in angular impulse during quadrupedal walking with a unilateral bone-anchored passive transtibial prosthesis. In Specific Aim 3, I determined the amount of skin and bone ingrowth into the SBIP after the residual tibia had been loaded during natural motor activities including level and slope walking. The results of these investigations showed purposeful adoption of the bone-anchored prosthesis into the animals’ chosen gait strategies. More specifically, normal ground reaction forces produced by the prosthetic limb were of substantial magnitudes (at least 50% of the pre implantation level), and tangential ground reaction forces, while significantly reduced, were statistically greater than zero and in the appropriate direction and timing across the gait cycle. Frontal-plane stability metrics deviated from the intact values to a lesser extent than in similar studies in human prosthetic gait. The histological results revealed deep bone and skin integration highly correlated with the duration of implantation and exceeded ingrowth of in a non-locomotive subject of similar implantation times. This study has provided important new information about the ability of the novel SBIP implants to be utilized for anchoring limb prostheses and about how the motor system of a quadrupedal animal adapts to a partial loss of the limb’s ability to absorb and generate mechanical energy for locomotion.
