OBESITY IN TOTAL HIP ARTHROPLASTY, DOES IT REALLY MATTER? A META-ANALYSIS.

Background A lot of discussion persists whether obesity negatively influences the outcome of hip arthroplasty. Current literature does not answer this question, since manuscripts showing a worse outcome and those showing a similar outcome can both be found. We performed a meta-analysis with the primary research question whether obesity has a negative influence on short and long term outcome of total hip arthroplasty. Methods A search of the literature was performed and studies comparing the outcome of hip arthroplasty in different weight groups were included. Methodology of the included studies was scored according to the Cochrane guidelines. Data extraction and pooling of the data was performed. For continuous data a weighted mean difference and for dichotomous variables a weighted Odds ratio was calculated. Heterogeneity was calculated using I2 statistics. Results A total of 15 studies were available for data-extraction. Dislocation occurred more often in obese with an Odds ratio of 0.54 (95%CI: 0.38–0.75) (10 studies, n = 8634). Aseptic loosening occured more often in obese with an Odds ratio of 0.64 (95% CI 0.43–0.96)(6 studies, n = 5137). Infection occured more often in obese with an Odds Ratio of 0.3 (95%CI: 0.19–0.49) (10 studies, n = 7500). Venous thromboembolism occured more often in obese with an Odds Ratio of 0.56 (95%CI: 0.32–0.98) (7 studies, n = 3716). For septic loosening and intraoperative fractures no difference was found, probably due to low power. Subjective outcome measurements did not allow Pooling due to high heterogeneity (I2 = 68%). Conclusions We conclude that being obese; ergo having a BMI of more than 30 certainly has a negative influence on total hip replacement.