The effects of elective total knee arthroplasty on the activation of markers of inflammation, coagulation and endothelial dysfunction

Total knee arthroplasty is a common elective orthopaedic procedure. The surgery itself causes soft tissue and bony trauma leading to a systemic response which includes endocrinological, immunological and haematological events. This thesis aims to investigate the potential association between total knee arthroplasty and such markers of inflammation, endothelium and coagulation. The study consisted of 4 groups; group 1 underwent an uncemented total knee arthroplasty; group 2 underwent a cemented total knee arthroplasty; group 3 underwent an uncemented total knee arthroplasty but received an intra-operative infiltration of local anaesthetic; group 4 underwent an uncemented total knee arthroplasty but had a post-operative drain for 24hours. Blood sampling was undertaken pre-operatively and at day 1 and day 7 post-operatively for the white cell count, platelets, neutrophils, C-reactive protein, interleukin 6, e-selectin, soluble CD40L, tissue plasminogen activator, von Willebrand factor, CD40 and CD1442a. Statistical analysis was undertaken in the form of pair sampled t-tests between group 1 and each of the other three groups. Although there some significant changes in one or two of the variables between the groups the only variable which demonstrated a significant difference in all comparisons was the CD1442a count. The exact role of CD1442a is unclear but there evidence to suggest that it may reflect the inflammatory and thrombotic process or contribute directly to the ongoing atherothrombogenesis. During the statistical analysis it was noted that the majority of the variables showed no clear statistical difference between the groups. In chapter 7 an ANOVA / Freidman analysis demonstrated that all but one of the variables, the CD1442a count, showed no statistical difference between all four groups. This allowed all the variables to be collated and presented as the single largest cohort study to date demonstrating the effects of total knee arthroplasty on the markers of inflammation, endothelium and coagulation. All the variables assessed showed a statistically significant change from pre-operative levels to day 7 post operation. 3 In summary our studies demonstrate that total knee arthroplasty results in activation of common markers of inflammation, endothelium and coagulation. These changes may explain the increased incidence of venous thrombosis and thrombo-embolism post-operatively as well as a potential risk of venous thrombo-embolism