The purpose of this study is to evaluate the effectiveness of a progressive resistance rehabilitation program (PROG) after total knee arthroplasty (TKA) compared to a traditional rehabilitation program (TRAD).

The investigators hypothesized:

• PROG will result in greater improvements in functional outcome measures such as: stair climbing test (SCT), timed-up-and-go test (TUG), six minute walk test (6MW), the Knee Injury and Osteoarthritis Outcome Survey (WOMAC), and knee range of motion (ROM).
• PROG will result in greater improvements in quadriceps muscle strength gains after TKA compared to TRAD.
• PROG will result in greater improvements in muscle mass and central activation compared to TRAD.

Over 500,000 total knee arthroplasties (TKAs) are performed each year in the United States to alleviate pain and disability associated with knee osteoarthritis (OA), and this number is expected to grow to 3.48 million per year by the year 2030. TKA reduces pain and improves self-reported function compared to pre-operative levels, but post-operative deficits in walking speed (20% slower) and stair climbing speed (50% slower) can persist for years. Stair climbing performance is the single largest residual deficit after TKA with seventy-five percent of TKA patients reporting difficulty negotiating stairs after surgery. Collectively, these findings suggest that current rehabilitation does not adequately target the impairments that lead to long-term deficits in functional mobility after TKA.

The aim of the proposed trial is to evaluate the effectiveness of a progressive resistance rehabilitation program (PROG) after TKA compared to a traditional rehabilitation program (TRAD). The PROG intervention will involve intensive rehabilitation using progressive resistance exercise and faster progression to functional strengthening exercises. The TRAD intervention represents the synthesis of previously published TKA rehabilitation programs. Our preliminary data suggest that the PROG intervention has low risk and results in improved functional mobility and muscle strength. The investigators will measure function and strength at six time points (pre-op; 1, 2, 3, 6, and 12 months after TKA). The investigators will also evaluate the contribution of changes in muscle mass (atrophy/hypertrophy) and central activation to changes in muscle strength following PROG and TRAD interventions.

Inclusion Criteria:

• undergoing a primary, unilateral knee arthroplasty
• body mass index < 40 kg/m2

Exclusion Criteria:

• severe contralateral leg OA (< 5/10 pain with stair climbing) or other unstable orthopaedic conditions that limit function
• neurological conditions that affect muscle function
• vascular or cardiac problems that limit function
• uncontrolled diabetes
• pregnancy