The safety and efficacy of outpatient total hip arthroplasty in very obese patients.

Abstract

As the number of patients who undergo total joint replacement as an outpatient continues to increase, it is essential that the safety and efficacy of this form of treatment is maintained. The aim of this study was to examine the outcome in a series of very obese patients who underwent total hip arthroplasty (THA) as an outpatient. A prospective database was used to identify 381 patients who underwent THA as an outpatient. Using case-control matching based on age, sex, and American Society of Anesthesiologists grade, 51 very obese patients with a BMI > 35 kg/m² were matched to 51 patients with a BMI < 35 kg/m² who underwent THA as an outpatient. In a subsequent analysis, 47 patients (41 THAs) from the same very obese cohort were matched to 47 very obese patients who underwent THA as an inpatient. For each group, readmission within 90 days, return to the emergency department (ED) within 90 days, adverse events, and reoperations were recorded. The mean BMI of the very obese outpatient group was 40 kg/m² (35 to 55); their mean age was 61 years (38 to 78). The mean BMI of the outpatients with a BMI < 35 kg/m² was 27 kg/m² (17 to 34); their mean age was 61 years (33 to 78). The mean BMI of the very obese inpatient group was 40 kg/m² (35 to 55); their mean age 62 years (34 to 77). Between the two outpatient groups, the rate of adverse events was significantly higher in the very obese group (15.69% compared with 1.96% (p = 0.015)). The reoperation rate was also significantly higher in the very obese group (five cases compared with none; p = 0.022). The rate of readmission and return to the ED within 90 days did not differ significantly between the groups (p = 0.299 and p = 0.092, respectively). There was no significant difference for all outcomes between the very obese patients who were treated as an outpatient and those who were treated as an inpatient. The very obese group had significantly higher rates of adverse events and reoperations compared with those with a BMI < 35 kg/m², but there was no difference when they were compared with a matched cohort of very obese patients who were treated as an inpatient. Caution must always be taken to identify the ideal candidates for outpatient surgery. However, BMI should not be used as a sole variable for deciding whether THA should be undertaken as an inpatient.