Exercise With Blood Flow Restriction To Improve Muscular And Physical Function After Total Knee Arthroplasty

Abstract

After a total knee arthroplasty (TKA), quadriceps strength and physical function can be impaired for several years. Blood flow restriction (BFR) exercise is an effective method to improve muscular and physical function in clinical populations with knee joint pathologies. To date, there are two case studies documenting application of BFR after TKA. A next step is to determine the feasibility of BFR in a larger TKA cohort. PURPOSE: To evaluate the effectiveness of a 10wk home-based BFR exercise program to improve muscular and physical function after TKA. METHODS: Six adults (age: 59±9yrs, BMI: 33±5) with a unilateral TKA (2.7±1.7yrs post-surgery) performed body weight half squats, isolated knee extension using a resistance band, and walking exercises with BFR 3x/wk for 10wk. During exercise, blood flow in the affected limb was restricted using a 15cm wide thigh cuff inflated to 50% of limb occlusion pressure which was identified using Doppler ultrasound. Outcome measures of vastus lateralis thickness, maximal knee extensor isometric torque, and physical function (repetitions performed during 30s chair stand test, distance covered during 6min walk test) were assessed at baseline and post-training. RESULTS: Participants completed 98% of the home-based BFR training sessions and tolerated the exercise program well as joint pain (0.6±0.1cm) and muscle soreness (0.5±0.1cm) were very low (0-10cm visual analogue scale). Vastus lateralis thickness and knee extensor strength in the affected leg increased by 18±11% and 17±13%, respectively (both P<0.05). After training, number of repetitions during the 30s chair stand test increased (11±2 vs. 18±4 repetitions, p<0.01) and this change (6 repetitions) exceeded the minimally important clinical difference. There was a significant increase in distance covered during the 6min walk test (511±28 vs. 556±36m, 9±7%, p=0.03) but this improvement (46m) did not exceed the clinical threshold. CONCLUSION: Results from this pilot study are promising and suggest that home-based BFR exercise can be feasible, safe, and effective for improving muscular and physical function after TKA. Further research is needed to confirm these initial findings in a larger randomized TKA control trial.