Results of Cemented Posterior-Stabilized TKA in Obese Patients with an Average 10 Year Follow-up

Abstract Introduction Obese and morbidly obese patients undergoing primary Total Knee Arthroplasty (TKA) place significant stress at the bone-cement-implant interface over the life of the patient. The purpose of this study was to evaluate results of cemented, posterior stabilized (PS) TKA in obese and morbidly obese patients at an average follow-up of 10 years. Methods Retrospective study of 181 patients who had a cemented, PS TKA between 2000 and 2013 with BMI >35 at time of surgery. Clinical data and radiographs evaluated along with survivorship, complications, and revisions. Minimum follow-up was 5 years with an average follow-up of 10 years. Results There were 135 women and 46 men in the study, with mean age of 60.2 years (range: 43-80), mean BMI of 42.0 (35.1-66.1) and an average follow-up of 10 years (range 5-18). There were a total of 39 failures (22%) that underwent revision TKA surgery with mean time to revision of 8 years. Failures included: 25 (14%) cases of aseptic loosening; 9 (5%) polyethylene wear; 2 (1%) prosthetic joint infection; and 3 additional revisions for instability, pain and stiffness. There were a total of 11 cases of isolated tibial component loosening and 13 for both tibial and femoral loosening. Survivorship at 15 years with aseptic loosening as the endpoint was 86.7%, and for all causes 79.6% at 15 years. Conclusion Aseptic loosening is the leading cause of failure following TKA in obese and morbidly obese patients with decreasing survivorship from 96.1% to 91.2% and 86.7% at 5, 10, and 15 years, respectively.