BMI: CLINICAL OUTCOMES

The majority of evidence demonstrates that patients of all body mass index (BMI) categories clinically improve following total joint arthroplasty. Patients with elevated BMI may recover more slowly, have less post operative physical activity (Paxton 2016), lower gait speed, less effective hip biomechanics, and achieve lower overall levels of satisfaction and function with total hip arthroplasty (THA) (McCalden 2011, Mukka 2020, Shadyab 2018, Davis 2011, Skutek 2016, Jackson 2009). However, despite lower total post operative outcome scores, the magnitude of improvement in these scores in patients with elevated BMI is equivalent to those of patients with normal BMI (Cleveland Clinic 2020, Liljensoe 2019, McLawhorn 2017). It should be noted that in many studies, elevated BMI was considered greater than 30. While studies of patients with higher BMIs (e.g., > 40) showed similar results, the available data is more limited in this population.

Benefits/Harms of Implementation
There are no harms associated with the implementation of this option.

Outcome Importance
It is important to understand that total hip arthroplasty patients show dramatic increases in their quality of life at all BMI levels.

Cost Effectiveness/Resource Utilization
Total hip arthroplasty has been shown to be cost- effective. Understanding that patients of all BMI levels have improved quality of life and patient- reported outcomes may expand access to this cost- effective surgical intervention.

Acceptability
It is accepted that BMI may influence the outcome of total hip arthroplasty.

Feasibility
It is feasible to determine BMI and educate patients preoperatively on its impact on post operative outcomes.

Future Research
Future research is warranted to determine the levels of improvement in patient reported outcomes after total hip arthroplasty based on BMI classes. Further research is also warranted to determine if certain patient reported outcomes improve more over others in patients with an elevated BMI. It is also necessary to determine if patient reported outcomes improve if BMI is reduced with preoperative weight loss before proceeding with THA.