Doctoral Thesis Proposal

Georgia Institute of Technology, School of Biological Sciences

February 27, 2017, 3:00pm, Room 1253, 555 14th St NW

Joshua R. Jarrell

Title: Quadrupedal locomotion with a unilateral bone-anchored transtibial prosthesis in the cat

Committee Members: Boris I. Prilutsky, Ph.D. (Advisor); T. Richard Nichols, Ph.D.; Johnna S.

Temenoff, Ph.D.; Young-Hui Chang, Ph.D.; and W. Lee Childers, Ph.D.

Abstract

Bone-anchored limb prostheses offer numerous advantages over conventional socket-supported

prostheses. Loads on a bone-anchored prosthetic limb during natural activities are directly

transmitted to the residual bone that prevents damage of skin and other soft tissues in the case of

socket prostheses. 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 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 the

study is to examine if or how the motor system adapts to a unilateral, transtibial SBIPanchored

prostheses during locomotion in the cat. The general hypothesis to be tested is that

the SBIP will provide secure, infection free anchoring of a transtibial prosthesis and that will

permit the cats to adopt the prosthesis for stable quadrupedal locomotion. In Specific Aim 1 I

will examine the ability of the SBIP to serve as attachment for a unilateral, transtibial boneanchored

prostheses during walking in the cat. In Specific Aim 2 I will determine the amount of

skin and bone ingrowth into the SBIP after the residual tibia has been loaded during natural

motor activities including locomotion. In Specific Aim 3 I will determine margins of static and

dynamic stability during quadrupedal walking with a unilateral bone-anchored passive transtibial

prosthesis. This study will provide important new information about the ability of the novel SBIP

implant to serve for anchoring limb prostheses and about how the motor system of a quadrupedal

animal adapts to a partial loss of afferent sensory feedback and the ability to generate mechanical

energy for locomotion.