Prior bariatric surgery may decrease the rate of re-operation and revision following total hip arthroplasty.

AIMS: We compared the outcome of total hip arthroplasty (THA) in obese patients who previously underwent bariatric surgery and those who did not, in a matched cohort study.

PATIENTS AND METHODS: There were 47 THAs in the bariatric group (42 patients), and 94 THAs in the comparison group (92 patients). The mean age of the patients was 57 years in both groups (24 to 79) and 57% of the patients in both groups were women. The mean time between bariatric surgery and THA was five years (four months to 12 years) in the bariatric group. The mean follow-up after THA was three years (2 to 9).

RESULTS: The mean BMI improved from 49.7 kg/m(2) (35 to 75) prior to bariatric surgery to 35.3 kg/m(2) (21 to 49) at the time of THA (p < 0.001). Patients in the comparison group had an increased risk of re-operation (Hazard Ratio (HR) 3.2; 95% confidence intervals (CI) 1.3 to 9.5, p = 0.01) and revision (HR 5.4; 95% CI 1.5 to 34.5, p = 0.01) when compared with the bariatric group.

CONCLUSION: Patients had a dramatic improvement in BMI after bariatric surgery and those with prior bariatric surgery had a lower risk of re-operation and revision in the short- and mid-term after a subsequent THA. Larger prospective studies are required before it can be concluded that this extra surgery should be advised in these patients. Cite this article: Bone Joint J 2016;98-B:1180-4.