The purpose of our study is to examine the outcome of patients undergoing outpatient total hip arthroplasty with a BMI >35.

Case-control matching on age, gender (46% female;54%male), and ASA (mean 2.8) with 51 outpatients BMI≥35 kg/m² (mean of 40 (35–55)), mean age of 61 (38–78) matched to 51 outpatients BMI<35 kg/m² (mean of 27 (17–34)) mean age 61 (33–78). Subsequently 47 inpatients BMI≥35 kg/m² (mean of 40 (35–55)) mean age 62 (34–77) were matched outpatients BMI≥35 kg/m². For each cohort, adverse events, readmission in 90 days, reoperations were recorded.

Rate of adverse events was significantly higher in BMI ≥35: 15.69% verus 1.96% (p=0.039) with 5 reoperations in the BMI≥35 cohort vs 0 in the BMI<35 kg/m² (p= 0.063). Readmissions did not differ between groups (p=0.125). No significant difference for all studied outcomes between the outpatient and inpatients cohorts with BMI≥35 kg/m². The most complications requiring surgery/medical intervention (3B) were in the inpatient cohort of patients >35. The prevalence of Diabetes and Obstructive Sleep apnea was 21.6% and 29.4% for BMI>35 compared to 9.8% and 11.8%, for BMI <35, respectively.

Severely obese patients have an overall higher rate of adverse events and reoperations however it should not be used a sole variable for deciding if the patient should be admitted or not.