Increased Survivorship of Cementless versus Cemented TKA in the Morbidly Obese. A Minimum 5-Year Follow-Up

Background: Total knee arthroplasty (TKA) in the morbidly obese patients can be challenging with an increased risk of complications. Studies have shown increased aseptic failures with well-aligned cemented TKAs in the obese patient. The purpose of this study is to determine if TKA in the morbidly obese (body mass index inverted right perpendicular BMI inverted left perpendicular >= 40) using cementless implants would demonstrate improved results and survivorship compared to cemented TKA at a minimum 5-year follow-up. Methods: This is a retrospective study comparing clinical results of cemented vs cementless primary TKA with a posterior stabilized design TKA in morbidly obese (BMI >= 40) patients with minimal 5-year follow-up. There were 108 patients in the cementless group with a mean BMI of 45.6. In the cemented cohort, there were 85 cemented TKAs with a mean BMI of 45.0. Demographic, clinical, surgical, and radiographic data along with complications were extracted for all study patients. Results: There were 5 failures requiring revision in the cementless group, including 1 for aseptic tibial loosening (0.9%). In the cemented group, there were 22 failures requiring revision, including 16 implants for aseptic loosening (18.8%; P = .0001). Survivorship with aseptic loosening as the endpoint was 99.1% in the cementless group vs 88.2% in the cemented cohort at 8 years (P = .02). Conclusion: Morbidly obese patients (BMI >= 40) have a higher failure due to aseptic loosening with cemented TKA with decreasing survivorship over time. The use of cementless TKA in morbidly obese patients with the potential of durable long-term biologic fixation and increased survivorship appears to be a promising alternative to mechanical cement fixation. (C) 2018 Elsevier Inc. All rights reserved.