CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Number 380, pp. 99–107 © 2000 Lippincott Williams & Wilkins, Inc. 99 The higher costs associated with teaching hospi- tals have received some attention in the litera- ture. The objective of the current study was to de- termine the increase in resource consumption associated with resident education in knee arthroplasty surgery. Seventy-four patients who underwent primary total knee arthroplasty in the same hospital were studied (50 private practice and 24 teaching practice). Time in the operating room and medical severity of illness were noted. Hospital charges were used as a measure of re- source consumption. In addition, length of stay and in-hospital consultations and complications were observed. Kruskall-Wallis, chi square, and stepwise multiple regression analysis were per- formed. The mean age of the patients was 68 years. Patients who underwent surgery at the teaching service had higher charges ($30,311  $3325 versus $23,116  $3341) and longer times in the operating room (190  19 minutes versus 145  29 minutes). These patients also had a trend toward more associated comorbid medical conditions (0.71 versus 0.42). Stepwise multiple regression analysis showed that teaching was the most important predictor of charges and operat- ing room time. The results show a 22% increase in perioperative resource consumption for patients who underwent surgery at a teaching service. The measured increase in cost is significantly lower than what has been reported in other series (82%). At the teaching institution, the anesthesia and orthopaedic surgery residents work together on all cases and perform a significant percent of the procedures under direct supervision. The in- creased resource consumption observed in a teaching service is most likely attributable to the hands-on approach taken to train residents. The cost of training medical students has re- ceived much attention in the literature. 8,13,21,35 It has been estimated that on the average, so- ciety pays between $50,000 and $90,000 to train a medical student. 13,20 For the most part, these funds are obtained through a combina- tion of tuition and federal funds. The cost of training residents also has received some at- tention. 1,2,7,9,10,14,21,32,36 The direct costs of training residents has been estimated to be ap- proximately between $7500 and $185,000 per resident per year. 4 The total amount of money spent in the United States on direct graduate medical educa- tion costs for 1997 exceeded 18 billion dollars. 17 These dollars currently are obtained from Medicare, Medicaid, the Department of De- fense, and the Department of Veterans’ Af- The Cost of Teaching Total Knee Arthroplasty Surgery to Orthopaedic Surgery Residents Carlos J. Lavernia, MD; Rafael J. Sierra, MD; and Ruben A. Hernandez, MD From the Division of Arthritis Surgery, Department of Orthopedic Surgery, University of Miami, School of Medicine, Miami, FL. Reprint requests to Carlos J. Lavernia, MD, 1321 North- west 14 th Street, Suite 203, Miami, FL 33125.