Obesity & Hypertension are Determinants of Poor Hemodynamic Control during Total Joint Arthroplasty: A Retrospective Review

Background: Proper blood pressure control during surgical procedures such as total joint arthroplasty (TJA) is considered critical to good outcome. There is poor understanding of the pre-operative risk factors for poor intra-operative hemodynamic control. The purpose of this study is to identify risk factors for poor hemodynamic control during TJA. Methods: We performed a retrospective cohort analysis of 118 patients receiving TJA in the Dominican Republic. We collected patient demographic and comorbidity data. We developed an a priori definition for poor hemodynamic control: 1) Mean arterial pressure (MAP) 135% of preoperative MAP. We performed bivariate and multivariate analyses to identify risk factors for poor hemodynamic control during TJA. Results: Hypertension was relatively common in our study population (76 of 118 patients). Average preoperative mean arterial pressure was 109.0 (corresponding to an average SBP of 149 and DBP of 89). Forty-nine (41.5%) patients had intraoperative blood pressure readings consistent with poor hemodynamic control. Based on multi-variable analysis preoperative hypertension of any type (RR 2.9; 95% CI 1.3-6.3) and an increase in BMI (RR 1.2 per 5 unit increase; 95% CI 1.0-1.5) were significant risk factors for poor hemodynamic control. Conclusions: Preoperative hypertension and being overweight/obese increase the likelihood of poor blood pressure control during TJA. Hypertensive and/or obese patients warrant further attention and medical optimization prior to TJA. More work is required to elucidate the relationship between these risk factors and overall outcome

Placing a Price on Medical Device Innovation: The Example of Total Knee Arthroplasty

Background: Total knee arthroplasty (TKA) is common, effective, and cost-effective. Innovative implants promising reduced long-term failure at increased cost are under continual development. We sought to define the implant cost and performance thresholds under which innovative TKA implants are cost-effective. Methods: We performed a cost-effectiveness analysis using a validated, published computer simulation model of knee osteoarthritis. Model inputs were derived using published literature, Medicare claims, and National Health and Nutrition Examination Survey data. We compared projected TKA implant survival, quality-adjusted life expectancy (QALE), lifetime costs, and cost-effectiveness (incremental cost-effectiveness ratios or ICERs) of standard versus innovative TKA implants. We assumed innovative implants offered 5–70% decreased long-term TKA failure rates at costs 20–400% increased above standard implants. We examined the impact of patient age, comorbidity, and potential increases in short-term failure on innovative implant cost-effectiveness. Results: Implants offering ≥50% decrease in long-term TKA failure at ≤50% increased cost offered ICERs <$100,000 regardless of age or baseline comorbidity. An implant offering a 20$150,000 per QALY gained only among healthy 50–59-year-olds. Increasing short-term failure, consistent with recent device failures, reduced cost-effectiveness across all groups. Increasing the baseline likelihood of long-term TKA failure among younger, healthier and more active individuals further enhanced innovative implant cost-effectiveness among younger patients. Conclusions: Innovative implants must decrease actual TKA failure, not just radiographic wear, by 50–55% or more over standard implants to be broadly cost-effective. Comorbidity and remaining life span significantly affect innovative implant cost-effectiveness and should be considered in the development, approval and implementation of novel technologies, particularly in orthopedics. Model-based evaluations such as this offer valuable, unique insights for evaluating technological innovation in medical devices