Is Utilizing a Modular Stemmed Tibial Component in Obese Patients Undergoing Primary Total Knee Replacement Cost-Effective?
Introduction: There has been recent enthusiasm for the use of modular stemmed tibial components in obese (BMI ≥35kg/m2) patients undergoing primary total knee arthroplasty (TKA). This has been mainly driven by studies demonstrating statistically significant increases in the rates of aseptic tibial loosening (ATL) in this patient population. However, to our knowledge, no study has specifically evaluated the cost effectiveness of this current recommendation.
Methods: The following study was performed utilizing previously obtained data on the incidence of ATL in obese patients undergoing primary TKA. This data was then utilized to create a cost calculator that can evaluate the price point at which the use of a stemmed tibial component in all obese patients would be less than or equal to the costs of revision surgery if a stemmed implant was not utilized.
Results: Utilizing historical data with a revision rate of 4% for aseptic loosening of the tibia on obese patients, a cost calculator was developed. The cost calculator requires the input of expected or known incidence of ATL utilizing a stem extension and the expected or known costs of revision for ATL.
Conclusion: The following cost calculator quickly determines a price point at which the use of a tibial stem offsets the costs of revision surgery. While this study may not provide an exact cost-effectiveness of modular stem fixation due to model limitations, it will hopefully initiate the discussion for providing more cost-effective individualized care for this patient population.
Campos P, Saguy A, Ernsberger P, Oliver E, Gaesser G. The epidemiology of overweight and obesity: public health crisis or moral panic? Int J Epidemiol. 2006;35(1):55-60. doi:10.1093/ije/dyi254.
Martin JR, Watts CD, Taunton MJ. Bariatric surgery does not improve outcomes in patients undergoing primary total knee arthroplasty. Bone Joint J. 2015;97-B(11):1501-1505. doi:10.1302/0301-620X.97B11.36477.
Wagner, E.R.; Kamath A.F., Fruth, K; Harmsen WS. BDJ. Influence of Body Mass Index on Total Knee Arthroplasty Outcomes. J Bone Jt Surg. 2015.
D’Apuzzo MR, Novicoff WM, Browne JA. The John Insall Award: Morbid obesity independently impacts complications, mortality, and resource use after TKA. Clin Orthop Relat Res. 2015;473(1):57-63. doi:10.1007/s11999-014-3668-9.
Mason JB, Callaghan JJ, Hozack WJ, Krebs V, Mont MA, Parvizi J. Obesity in Total Joint Arthroplasty: An Issue With Gravity. J Arthroplasty. 2014;29(10):1879. doi:10.1016/j.arth.2014.09.002.
Martin JR, Fehring KA, Watts CD, Springer BD, Fehring TK. Radiographic Findings in Patients With Catastrophic Varus Collapse After Total Knee Arthroplasty. J Arthroplasty. 2018;33(1):241-244. doi:10.1016/j.arth.2017.08.014.
Abdel MP, Bonadurer GF, Jennings MT, Hanssen AD. Increased Aseptic Tibial Failures in Patients With a BMI ≥35 and Well-Aligned Total Knee Arthroplasties. J Arthroplasty. July 2015. doi:10.1016/j.arth.2015.06.057.
Fehring TK, Fehring KA, Anderson LA, Otero JE, Springer BD. Catastrophic Varus Collapse of the Tibia in Obese Total Knee Arthroplasty. J Arthroplasty. 2017;32(5):1625-1629. doi:10.1016/j.arth.2016.12.001.
Gopalakrishnan A, Hedley AK, Kester MA. Magnitude of cement-device interfacial stresses with and without tibial stemming: impact of BMI. J Knee Surg. 2011;24(1):3-8. http://www.ncbi.nlm.nih.gov/pubmed/21618932. Accessed July 10, 2017.
Parratte S, Ollivier M, Lunebourg A, Verdier N, Argenson JN. Do Stemmed Tibial Components in Total Knee Arthroplasty Improve Outcomes in Patients With Obesity? Clin Orthop Relat Res. 2017;475(1):137-145. doi:10.1007/s11999-016-4791-6.
Crawford DA, Berend KR, Nam D, Barrack RL, Adams JB, Lombardi Jr A V. Low Rates of Aseptic Tibial Loosening in Obese Patients With Use of High-Viscosity Cement and Standard Tibial Tray: 2-Year Minimum Follow-Up. 2017. doi:10.1016/j.arth.2017.04.018.
Abdel MP, Ast MP, Lee Y-Y, Lyman S, González Della Valle A. All-cause in-hospital complications and urinary tract infections increased in obese patients undergoing total knee arthroplasty. J Arthroplasty. 2014;29(7):1430-1434. doi:10.1016/j.arth.2014.02.013.
Alvi HM, Mednick RE, Krishnan V, Kwasny MJ, Beal MD, Manning DW. The Effect of BMI on 30 Day Outcomes Following Total Joint Arthroplasty. J Arthroplasty. 2015;30(7):1113-1117. doi:10.1016/j.arth.2015.01.049.
Dowsey MM, Choong PFM. Obese diabetic patients are at substantial risk for deep infection after primary TKA. Clin Orthop Relat Res. 2009;467(6):1577-1581. doi:10.1007/s11999-008-0551-6.
Thelwall S, Harrington P, Sheridan E, Lamagni T. Impact of obesity on the risk of wound infection following surgery: results from a nationwide prospective multicentre cohort study in England. Clin Microbiol Infect. July 2015. doi:10.1016/j.cmi.2015.07.003.
Odum SM, Springer BD, Dennos AC, Fehring TK. National obesity trends in total knee arthroplasty. J Arthroplasty. 2013;28(8 Suppl):148-151. doi:10.1016/j.arth.2013.02.036.
Maradit Kremers H, Visscher SL, Moriarty JP, et al. Determinants of Direct Medical Costs in Primary and Revision Total Knee Arthroplasty. Clin Orthop Relat Res. 2013;471(1):206-214. doi:10.1007/s11999-012-2508-z.
Nichols CI, Vose JG. Clinical Outcomes and Costs Within 90 Days of Primary or Revision Total Joint Arthroplasty. J Arthroplasty. 2016;31(7):1400-1406.e3. doi:10.1016/j.arth.2016.01.022.
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