The Journal of Arthroplasty , Volume 34 , Issue 3 , 433 - 438

Ninety-Day Costs, Reoperations, and Readmissions for Primary Total Hip Arthroplasty Patients of Varying Body Mass Index Levels

Ponnusamy, Karthikeyan E. et al.


The purpose of this study is to compare 90-day costs and outcomes for primary total hip arthroplasty patients between a nonobese (body mass index, 18.5-24.9) vs overweight (25-29.9), obese (30-34.9), severely obese (35-39.9), morbidly obese (40-44.9), and super obese (45+) cohorts.


We conducted a retrospective review of an institutional database of primary total hip arthroplasty patients from 2006 to 2013. Thirty-three super-obese patients were identified, and the other 5 cohorts were randomly selected in a 2:1 ratio (n = 363). Demographics, 90-day outcomes (costs, reoperations, and readmissions), and outcomes after 3 years (revisions and change scores for Short-Form Health Survey, Harris Hip Score, and Western Ontario and McMaster Universities Arthritis Index) were collected. Costs were determined using unit costs from our institutional administrative data for all in-hospital resource utilization. Comparisons between the nonobese and other groups were made with Kruskal-Wallis tests for non-normal data and chi-square and Fisher exact test for categorical data.


The 90-day costs in the morbidly obese ($13,134 ± $7250 mean ± standard deviation, P < .01) and super-obese ($15,604 ± 6783, P < .01) cohorts were significantly greater than the nonobese cohorts ($10,315 ± 1848). Only the super-obese cohort had greater 90-day reoperation and readmission rates than the nonobese cohort (18.2% vs 0%, P < .01 and 21.2% vs 4.5%, P = .02, respectively). Reoperations and septic revisions after 3 years were greater in the super-obese cohort compared to the nonobese cohort 21.2% versus 3.0% (P = .01) and 18.2% versus 1.5% (P = .01), respectively. Improvements in Short-Form Health Survey, Harris Hip Score, and Western Ontario and McMaster Universities Arthritis Index were comparable in all cohorts.


Super-obese patients have greater risks and costs compared to nonobese patients, but also have comparable quality of life improvements.

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