Ten-Year Mortality and Revision After Total Knee Arthroplasty in Morbidly Obese Patients.

Abstract

Although morbid obesity has been associated with early surgical complications after total knee arthroplasty (TKA), evidence of long-term outcomes is limited. We conducted a population-based study to determine the association between morbid obesity and 10-year survival and revision surgery in patients undergoing primary TKA. A cohort study of 9817 patients aged 18-60 years treated with primary TKA from April 1, 2002 to March 31, 2007 was conducted using Ontario administrative health-care databases of universal health-care coverage. Patients were followed up for 10 years after TKA. Risk ratios (RRs) of mortality and TKA revision surgery in patients with body mass index > 45 kg/m² (morbidly obese patients) compared with body mass index ≤45 kg/m² (nonmorbidly obese) were estimated adjusting for age, sex, socioeconomic status, and comorbidities. About 10.2% (1001) of the cohort was morbidly obese. Morbidly obese patients were more likely to be female than nonmorbidly obese patients (82.5% vs 63.7%, P < .001) but otherwise similar in characteristics. Morbidly obese patients had higher 10-year risk of death than nonmorbidly obese patients (adjusted RR 1.50, 95% confidence interval 1.22-1.85). About 8.5% (832) of the patients had at least 1 revision procedure in the 10 years after TKA; revision rates did not differ by obesity (adjusted RR 1.09, 95% confidence interval 0.88-1.34). Morbidly obese patients ≤60 years had a 50% higher 10-year risk of death but no difference in the risk of revision surgery. Results of this population-based study inform evidence-based perioperative counseling of morbidly obese patients considering TKA.