Total knee arthroplasty (TKA), one of the most common surgical procedures reimbursed by Medicare, provides improved function and pain relief. The most devastating complication related to this surgery is infection, also known as prosthetic joint infection (PJI). The recommended management for PJI depends on a number of factors but ideally involves a surgical debridement of the joint and surrounding tissues. Despite surgical intervention and long courses of intravenous antibiotics, the failure rate for these treatments can reach 60% which leads to multiple surgeries and significant cost to the patient and health care systems. There is a large gap in our current understanding of what constitutes an adequate debridement. The hypothesis of this proposal is that variability exists in the concentration of biomarkers, regional vascularity, and immune cell response dependent on the depth of debridement and the presence or absence of infection. Evaluation in the clinical setting and in a preclinical PJI model will allow for the development of methods to detect the adequacy of debridement and improve significant failure rates in the treatment of PJI. The proposed aims will demonstrate the variability in the tissue environment in the infected and non- infected setting. The results of this variability will be demonstrated in both clinical samples obtained from discarded surgical tissue and in a preclinical model to allow for further development of translational treatments and techniques. Preliminary results in this proposal demonstrate the ability to detect regional variations in inflammatory biomarkers, the ability to detect local vascularity via laser assisted fluorescent angiography, and the assessment of immune cell activation via extracellular flux analysis.
In Aim 1, clinical samples from revision knee arthroplasties will be compared in the presence or absence of infection and according to the depth of debridement. A preclinical model will be validated with the results obtained from the clinical samples.
Aim 2 will assess the regional vascular environment before and after debridement to demonstrate the alteration of perfusion as a result of infection and surgical debridement.
In Aim 3, the bioenergetic profile of cells located within a tissue bed in a revision knee and a preclinical model will be defined. This information will further the understanding of the local environment of a revision knee joint and allow for comparison to a preclinical model. This ambitious research plan has been developed with the assistance and guidance of a multidisciplinary mentor team of respected investigators and leaders in their fields. The mentor team and advisory panel were selected based on longstanding relationships, known expertise, and track record of successful mentorship of junior faculty and investigators. The career development goals outlined will be achieved through didactic classes, workshops, and conferences in addition to the direct mentoring of the group. The preliminary data and training acquired will position Dr. Dietz to achieve independence with R01 funded research.
Infections after total joint replacement are devastating complications requiring prolonged treatments, costly hospitalizations, and multiple surgeries; the five-year mortality rate is similar to colon cancer. Surgery to remove infected tissues and materials is common but incomplete understanding of what tissues to remove or leave behind contributes to the high failure rates and poor outcomes associated with this complication. To improve treatment, we need to more fully understand the environment in which the infection occurs.
