Abstract
BACKGROUND: Blood flow restriction (BFR) therapy has been proposed to help patients build strength with fewer repetitions than standard physical therapy (PT). We sought to determine if BFR would improve quadriceps and hamstring strength in patients with instability and perceived weakness >1 year after primary total knee arthroplasty (TKA). METHODS: We retrospectively reviewed 48 patients with painful TKAs and flexion instability as well as quadriceps and hamstring weakness who performed a 6-week PT program and received isokinetic strength measurements (ISMs). Thirty-six patients completed a standard PT program (non-BFR) and 12 patients completed a BFR regimen. ISMs were taken before and after PT to quantify quadriceps and hamstring power, torque, and work compared to the contralateral leg. Statistical analysis was conducted on pre-PT and post-PT ISMs and decisions for revision surgery. RESULTS: There were no differences in ISMs after PT between the BFR and non-BFR groups. The non-BFR group showed statistically significant strength improvements in flexion but not extension (+28.7%-32.8%, P = .0145-.255). Although no significant difference was found in the BFR group, they saw improvements in all extension strength metrics (19.4%-23.4%, P = .3315-.3901) and flexion (25.7%-29.9%, P = .1994-.2392). No difference was observed between the groups in the rates of subsequent revision TKA (8.3% vs 16.7%, P = .3362). CONCLUSION: BFR did not improve quadriceps and hamstring strength compared to PT alone in patients with instability and weakness after TKA. Over 80% of total patients chose to avoid revision TKA after completion of focused PT with or without BFR.