Cementless Total Knee Arthroplasty Is Associated With Improved Outcomes in Patients Who Have a Body Mass Index of 35 or More.

Abstract

Indications for cementless fixation in total knee arthroplasty (TKA) remain unclear despite increasing use. Previous findings have suggested that obese patients have favorable outcomes with cementless TKA, but evidence is sparse. This paper compared the following outcomes in patients who have a body mass index (BMI) of 35 or more: (1) mechanical complications, including periprosthetic fracture and aseptic loosening; (2) infectious complications, including periprosthetic joint infection (PJI) and surgical site infection; 3) venous thromboembolism; and 4) aseptic revision through five years postoperatively. A national all-payer database identified patients who had a BMI of 35 or more undergoing primary TKA for osteoarthritis from 2010 to 2021 (n = 91,221). Patients who had a history of trauma, malignancy, or rheumatoid arthritis were excluded. International Classification of Diseases-10th edition codes determined fixation type. Propensity score matching for age, Charlson Comorbidity Index, sex, alcohol abuse, tobacco use, and diabetes yielded cementless (n = 5,416) and cemented (n = 18,525) cohorts. Chi-square analyses were completed for respective complications at 90 days, one year, two years, and five years postoperatively. Odds ratios (ORs) were calculated using 95% confidence intervals (CIs). Cementless fixation was associated with decreased rates of aseptic loosening at 90 days (OR 0.39, 95% CI 1.02 to 1.48), one year (OR 0.65, 95% CI 0.45 to 0.96), 2 years (OR 0.72, 95% CI 0.54 to 0.96), and five years (OR 0.68, 95% CI 0.54 to 0.87). The cementless cohort also demonstrated reduced PJI at five years (OR 0.80, 95% CI 0.69 to 0.92). The incidences of periprosthetic fracture, surgical site infection, venous thromboembolism, and aseptic revision were comparable between groups (P > 0.05). Among patients who had a BMI ≥ 35, cementless TKA was associated with decreased odds of aseptic loosening through five years and reduced PJI at five years, supporting its use in this population.