Clinical, Kinematic, and Kinetic Analysis of Knee Arthrodesis in Support of the Design of a Novel Treatment Alternative

The following body of work is the result of collaborative efforts between researchers at Clemson University and a team of practicing orthopedic surgeons. It begins with the identification of an inadequately addressed clinical need, the treatment of severe knee dysfunction, in the practices of our clinical collaborators. A case report, reviewing the condition of five affected patients, is presented to provide initial evidence for the existence of this need. A thorough review of the causes and currently available treatment options for knee dysfunction, including arthrodesis, is provided to clarify the need and establish its widespread significance, and a novel treatment model is proposed and discussed with respect to existing treatments. In spite of a large number of recently published clinical case reports, the total number of affected patients has been heretofore unreported. In order to establish this figure in further support of the need for an alternative treatment, a large database of hospital discharge records is analyzed. An estimate of the frequency of knee arthrodesis is provided, and the affected patients are characterized. Having quantified the incidence of the primary treatment method, and thus provided an estimate of the affected patient subpopulation, the effect of this treatment on lower body biomechanics is addressed. A gait analysis study was designed to simulate knee arthrodesis in normal, healthy subjects, providing a comprehensive quantification of joint kinematics and kinetics and allowing for the investigation of further hypotheses regarding the effects of treatment. In spite of a number of reported cases of mechanical failure in knee arthrodesis implant designs, the robustness of these designs against such failure has been a neglected subject in literature. Data obtained from a previously conducted gait analysis study is used to estimate the loading conditions at an immobilized knee through the construction of a computational biomechanical model. The purpose of this model is to estimate the resultant effects of knee immobilization on the musculoskeletal system during gait, and estimates of muscle and joint loading patterns are provided. Together, this knowledge is used to assist in the design and development of a novel treatment model, in the form of a salvage total knee replacement. This patent pending treatment is designed to subsume existing, less constrained treatment methods as well, broadening its applicability. It has been refined over the course of several design cycles, which were informed by the regulatory guidelines for medical device design in the United States. Prototyping techniques have been used throughout the design process to demonstrate proof of concept. This work is intended to establish the significance of an unmet clinical need, characterize the patient subset and treatment patterns affected by the need, quantify the biomechanical conditions in the bodies of affected patients, and ultimately facilitate the translation of a proposed medical device from concept to clinical use