Economic Decision Model for First-Time Traumatic Patellar Dislocations in Adolescents Benedict U. Nwachukwu, * y MD, MBA, Conan So, z BS, William W. Schairer, y MD, Beth E. Shubin-Stein, y MD, Sabrina M. Strickland, y MD, Daniel W. Green, y MD, and Emily R. Dodwell, y MD, MPH Investigation performed at the Hospital for Special Surgery, New York, New York, USA Background: The surgical management of traumatic patellar dislocations in adolescents is associated with a lower rate of recur- rent dislocations compared with nonoperative care. However, the attendant cost of surgery and the quality-of-life benefit of a sur- gical treatment strategy are unclear. Purpose: To compare the cost-utility of 3 management strategies for acute first-time patellar dislocations in adolescents: (1) non- operative treatment only, (2) initial nonoperative treatment with surgery only for recurrent dislocations, and (3) immediate surgery. Study Design: Economic and decision analysis; Level of evidence, 2. Methods: A 10-year state-transition Markov model was constructed to compare the cost-utility of the 3 index treatment proto- cols. Utilities used to define health states were derived from a telephone interview of 60 adolescents with a history of acute patel- lar dislocations. The probability of transition between each health state was informed by the available literature. Direct costs were estimated using a statewide ambulatory surgery database, and indirect costs were estimated based on parental lost productivity. Effectiveness was expressed in quality-adjusted life years (QALYs). The principal outcome measure was the incremental cost- effectiveness ratio (ICER). Results: In the base case for our model, nonoperative treatment only was the least costly ($7300) but also the least effective (5.30 QALYs); initial nonoperative treatment with delayed surgery cost $10,500 for a 5.93 QALY benefit, while immediate surgical treat- ment cost $17,100 and provided 6.32 QALY benefits. Compared with nonoperative treatment only, initial nonoperative treatment with delayed surgery was associated with an ICER of $5100 per QALY. When immediate surgery was compared with a strategy of delayed surgery, immediate surgery provided incremental benefits at an ICER of $17,000 per QALY. The model was sensitive to the probability of surgical versus nonoperative treatment to achieve a full return to preinjury activity versus an intermediate lower state. When the probability of achieving a full return to preinjury activity with initial nonoperative treatment exceeds 47.5% (com- pared with 34.2% in the base case), then initial nonoperative treatment with delayed surgery is preferred to immediate surgery. Similarly, when the probability of achieving a full return to full preinjury activity with surgery falls below 51% (compared with 64% in the base case), then delayed surgery after initial nonoperative treatment is preferred. Conclusion: Immediate surgery and delayed surgical treatment are both cost-effective treatment options; however, immediate surgical treatment provides the highest QALY gains within a 10-year time horizon. Our model sensitivity analysis highlights the role of optimizing functional and quality-of-life benefits in the treatment of acute traumatic patellar dislocations. These findings have implications for clinical guidelines and policy decisions relating to adolescent patellar dislocations. Keywords: cost-utility analysis; patellar dislocation; medial patellofemoral ligament; quality of life; cost A patellar dislocation is a common acute knee injury, 8,19 accounting for approximately 3% of all knee injuries. 1,40 The annual incidence of first-time patellar dislocations in children and adolescents has been reported to be 43 per 100,000. 19 The traditional treatment for acute patellar dis- locations has been nonoperative management consisting of brief immobilization, followed by physical rehabilita- tion. 5,11 Surgical intervention for a first-time dislocation has been reserved for cases with osteochondral damage, other knee concomitant injuries, or anatomic deficiency. 40 The routine role of surgery for first-time traumatic patellar *Address correspondence to Benedict U. Nwachukwu, MD, MBA, Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA (email: nwachukwub @hss.edu). y Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York, USA. z University of Maryland School of Medicine, Baltimore, Maryland, USA. The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. The American Journal of Sports Medicine, Vol. XX, No. X DOI: 10.1177/0363546517703347 Ó 2017 The Author(s) 1