Background

The SWIFT trial, is a multi-site, prospective trial comparing knee physical function outcomes in patients with severe obesity who undergo bariatric surgery prior to TKA versus TKA only. This preliminary report compares knee outcomes in patients that completed bariatric surgery only vs. patients that had TKA without bariatric surgery.

Methods

Knee outcomes for this analysis included Visual Analog Scale for knee pain, Timed Up and Go, 30-second Chair Stand, and 40-meter fast paced walk. The percent with >10% improvement in knee outcomes were compared between groups using logistic regression (adjusting for age and baseline BMI).

Results

This report includes 17 TKA eligible patients that completed 6-month follow-up after bariatric surgery and another 17 patients that completed 6-month follow-up after TKA only. The groups had a similar sex distribution (18% males in the bariatric group and 12% in TKA group, p=0.999) but the bariatric group was younger (53 vs 60, p=0.0056) and had a higher baseline BMI (47.1 vs 40.7, p=0.0020). Although the percent with >10% improvement was consistently higher in the TKA group, these differences were not significant for Visual Analog Pain Scale (48% vs 41%, p=0.762), Timed Up and Go (65% vs 59%, p=0.750), 30-second Chair Stand (77% vs 41%, p=0.091), or the 40-meter fast paced walk (76% vs 44%, p=0.147).

Conclusions

Bariatric surgery results in modest improvements in knee outcomes in patients that are eligible for TKA and demonstrates potential to diminish the short term needs for knee replacement.