Restoring physical function after knee replacement: a cross sectional comparison of progressive strengthening vs standard physical therapy.

Objective: The purpose of this study is to compare the functional status of patients 12 months after total knee arthroplasty (TKA) who underwent progressive strengthening or standard of care rehabilitation to older adults without knee joint pain. Methods: This cross-sectional design study included 165 participants in the progressive strengthening group, 40 participants in the standard of care group, and 88 older adults (control group). The Knee Outcome Survey - Activity of Daily Living, knee active range of motion (ROM), quadriceps strength, and performance tests were compared between groups using a one-way ANOVA. The proportions of participants in both TKA groups who achieved the lower bound of the 95% confidence interval of the control group were compared using a Fisher's exact test. Results: Significant between-group effects were found for all variables (p < 0.001). The control group had better outcomes than both the progressive strengthening and standard of care groups (p < 0.001). Compared to the standard of care group, a higher proportion of participants in the progressive strengthening group achieved the lower bound cutoff for active knee extension ROM (p = 0.042), quadriceps strength (p = 0.032), and stair climbing time (p = 0.029). Conclusion: More participants in the progressive strengthening group had physical function that was similar to the healthy control group, when compared to the standard of care group. Progressive strengthening rehabilitation may be more effective in restoring normative levels of function after TKA than standard of care.