Anti-Gravity Treadmill Walking in Acute Rehabilitation of Total and Partial Knee Replacement Patients

Abstract

Trauma from surgery and limited functional movement of the knee following knee replacement surgery results in atrophy due to reduced anabolism of skeletal muscle proteins. The use of an anti-gravity (AG) treadmill in recovery to improve strength, functionality, and quality of life, attenuating this catabolic state, has yet to be investigated in this population. PURPOSE: To determine if AG treadmill training in conjunction with standard of care rehabilitation will augment or maintain overall lean mass and leg strength as well as improve physical function and clinical outcomes following knee replacement surgery. METHODS: Six men and six women (age 67.7 ± 5.8) underwent knee replacement surgery and were randomized into the AG or control (C) group. Both the AG and C group received standard of care physical therapy. In addition, the AG group walked 3 days per week for 12-weeks on the anti-gravity treadmill, starting at 50% body weight and completing the intervention at 95% body weight. Body composition, strength, and physical function measurements were obtained 3-weeks post-operation, as a baseline measurement (BL), and 6 and 12 weeks from the BL measurement. RESULTS: After Bonferroni corrections (P≤.017), statistically significant differences were achieved within but not between groups. The AG group, from BL to week 6, demonstrated significant improvements in quality of life (P=.017, +102%) and marked improvements in knee extension strength of the affected leg (P=.040, +108%). From BL to week 12, significant changes were made in the 10-meter walk test (P=.009, -28%). Notable percent changes were observed from BL to week 12 in lean body mass (AG +8.3%, C +1.4%), the five times sit-to-stand test (AG -51.9%, C -8.6%), and single leg anterior reach lower extremity on the affected leg (AG +42.3%, C -5.8%). CONCLUSION: 12 weeks of AG treadmill training prompts important improvements in quality of life and walking recovery compared to standard of care physical therapy alone. We continue to recruit subjects and with a larger sample size may be able to demonstrate statistically significant changes in strength, physical function, and clinical outcomes even with Bonferroni corrections.