Obesity and racial characteristics drive utilization of total joint arthroplasty at a younger age

Background: Obesity is a growing public health problem. Obesity increases the risk of requiring total joint arthroplasty (TJA). The purpose of this study was to examine the effect of obesity on the propensity for TJA in patients at our institution. We hypothesized that obese patients would be younger and more likely to be races other than non-Hispanic whites when compared to a normal weight cohort.

Methods: 568 consecutive patients undergoing primary TJA were reviewed. Demographic data and World Health Organization Body Mass Index (BMI) class were compared statistically, with age at time of TJA used as the main outcome of interest.

Results: The average age at TKA was 68.3 years, while the average age at THA was 67.5 years (p = 0.447 between procedure groups). Increased BMI class was associated with decreased age at TJA: normal weight patients were 12.2 and 11.4 years older than class III obese patients at the time of TKA and THA, respectively (p < 0.001). Among TKA patients, obese patients, when compared to non-obese patients, were significantly less likely to be non-Hispanic whites (p = 0.016). Among THA patients, class III obese patients were significantly less likely to be non-Hispanic whites (p = 0.007).

Conclusions: Obesity is a risk factor for both TKA and THA at a younger age. For patients in the study, for each unit increase in BMI, the age at TKA decreased by 0.56 years and age at THA decreased by 0.52 years. Obese patients were less likely to be non-Hispanic whites than normal weight patients.