Characterization and Potential Relevance of Randomized Controlled Trial Patient Populations in Total Joint Arthroplasty in the United States: A Systematic Review

A substantial number of randomized controlled trial (RCT) studies in total joint arthroplasty (TJA) are published each year in the United States (US). However, it is unknown how closely the demographic and clinical characteristics of these cohorts resemble that of the US patient population undergoing TJA. Thus, the purpose of this systematic review was to evaluate the patient characteristics of published RCTs in TJA in the US and to compare these characteristics against patient cohorts from national patient databases.RCT studies regarding primary TJA conducted in the US were selected. Key patient demographics were aggregated and compared against demographics characteristics of the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality National Inpatient Sample (NIS) and American College of Surgeons National Surgical Quality Improvement Program patient cohorts.One hundred and fifty-three RCTs fulfilled the inclusion criteria and were included. The total number of patients in the 153 RCTs was 24,135 patients. The average age of patients in the TJA RCT cohort was 65 years (53-80) while the NIS cohort was 67 years (18-90) (d = 0.21, effect size = small). The average body mass index of the TJA RCT cohort was 30.8 (18.2-37.6) while the National Surgical Quality Improvement Program cohort was 31.9 (14.1-59.6) (d = 0.18, effect size = small). For TJA, effect sizes for age, body mass index BMI, sex, ethnicity, smoking, and diabetes were all small or very small.Overall, the US RCT patient cohort for TJA does not differ substantially from the general patient population undergoing TJA in the United States. Differences in demographic and clinical characteristics between the TJA RCT cohort and database cohorts ranged from minimal to small, suggesting that these differences are unlikely to impact clinical outcomes.