Tumors Constitute a Majority of Total Knee Arthroplasty in Patients <21 Years Old: A United States Nationwide Analysis

Total knee arthroplasty (TKA) is rarely performed in patients under 21 years old, but the frequency of utilization of TKA in this population in the United States is not known. The purpose of this study was to evaluate trends in the use of TKA in patients21 in the United States. Additionally, we aimed to determine the characteristics of these patients and the hospitals in which this procedure is performed.We retrospectively reviewed the Kids&#39; Inpatient Database, a national weighted sample of all inpatient hospital admissions in the United States in patients21 years of age. We used International Classification of Diseases, Ninth Revision (ICD-9) and ICD-10 codes to identify patients undergoing TKA from 2000 to 2019 and determine a primary diagnosis. Descriptive statistics were calculated using the appropriate sample weights.The total weighted number of TKAs performed in patients21 years from 2000 to 2019 was 1,535. There were 70.9% of TKAs performed for a primary diagnosis of tumor, and the use of TKA for malignant tumors has increased. In contrast, the use of TKA for inflammatory arthritis/juvenile idiopathic arthritis decreased significantly over the study period. The majority of TKAs were performed in urban teaching hospitals with a large bed size.Approximately 1,535 TKAs have been performed in patients21 years from 2000 to 2019 in the United States. The majority of these procedures were performed for reconstruction after resection of a malignant tumor. The rate of TKA for inflammatory arthritis/juvenile idiopathic arthritis has decreased over the past two decades.