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Do the Ten-Year Functional Outcomes and Revision Rates of Total Hip Arthroplasty in Obese and Morbidly Obese Patients
Hua Shin Tan1, Deborah Snell1, Jinny Willis2
1Department of Orthopaedic Surgery and Musculoskeletal Medicine, University of Otago, Christchurch, Christchurch, New Zealand.
Background:
A prospective observational study with retrospective analysis of the data was carried out on 8,089 patients who underwent total hip arthroplasty (THA) at a single elective center between January 1, 2006, and November 30, 2022. Our aim was to examine whether obesity and morbid obesity have an effect on ten-year clinical outcomes and revision rates.
Methods:
The patients were divided into three groups: nonobese (body mass index [BMI] < 30), obese (BMI 30 to < 40), and morbidly obese (BMI ≥ 40). Our primary outcomes were the mean change in Oxford Hip Score and Western Ontario and McMaster's Universities Osteoarthritis Index up to 10 years to assess the clinical benefit of surgery. The secondary outcomes measured were the rate of revisions up to 10 years, rate/100 component years, time between primary THA and revision, reasons for revision (aseptic loosening, deep infection, dislocation, fractured femur), mean skin-to-skin time, American Society of Anesthesiologist Classification, and the 90-day mortality rate. The BMI data were not available for 1,130 patients (13.97%).
Results:
There was no difference in the absolute at 10 years and mean change in Oxford Hip Score and Western Ontario and McMaster's Universities Osteoarthritis Index up to 10 years between the groups. There was no difference in the absolute revision rate between the groups, although the obese and morbidly obese groups did have a higher rate of revision/100 component years and can expect a shorter time interval between THA and revision surgery compared to the nonobese groups. We did not find any significant association between obesity and the reasons for revision surgery, with the exception of fractured femur in the nonobese group.
Conclusions:
The ten-year functional outcomes and revision rates of THA do not justify restricting access to surgery on the basis of BMI.
