This study plans to learn more about the effects of physical therapy (PT) following a total hip arthroplasty (THA). The purpose of this study is to compare standard of care PT after THA with a physical therapy program specifically designed to integrate targeted core and hip muscle strength and functional training.
Over the next 20 years, the number of total hip arthroplasties (THAs) performed to alleviate pain and disability associated with osteoarthritis (OA) is expected to double to more than 500,000/year. Most patients report improved health-related quality of life following surgery; however, deficits in physical function and quality of life persist. Specifically, Veterans with THA have a higher prevalence of severe activities of daily living (ADL) limitations and report severe physical health-related quality of life deficits. The increased THA utilization, combined with long-term functional deficits which increase heath care utilization, suggests a need for targeted rehabilitation strategies to improve physical function for Veterans after THA. Movement compensations are a biomarker of functional decline in a variety of older adult populations. For patients with THA, persistent movement compensations are seen in activities of daily living, such as level walking, sit-to-stand transitions, and stair climbing. These movement compensations likely stem from a combination of poor muscle strength and a failure to integrate available muscle strength into functional movement. Functional strength integration (FSI) during daily tasks refers to the ability of the body to produce stable, coordinated movements. At the hip joint, optimal FSI is largely dependent on the ability of hip abductor muscles to produce sufficient hip abduction moments to stabilize the pelvis during unilateral stance tasks. Thus, inability to integrate hip abductor muscle strength during functional tasks results in poor pelvic stability and movement compensations. Lack of FSI possibly explains the deficits in functional recovery after THA. However, current rehabilitation practices do not target the integration of strength and functional movement to resolve movement compensations. Rehabilitation emphasizing functional strength integration after THA has the potential to substantially improve postoperative physical function by remediating movement compensations with greater hip abductor strength and recruitment during function, providing greater pelvic control and better movement quality. Therefore, the investigators propose a randomized controlled trial of 100 participants to determine if an 8-week functional strength integration (FSI) program after THA improves physical function and muscle performance more than control intervention (CON) after unilateral THA. The secondary goal is to determine if FSI improves movement compensations during functional activity (walking and stair climbing). Eight weeks of intervention will be initiated 2 weeks after THA to allow for early tissue healing. Outcomes will be assessed pre-operatively (PRE); intervention mid-point (after 4 weeks intervention; POST1); intervention end-point (after 8 weeks intervention; POST2) (primary endpoint); and late recovery (26 weeks after initiating rehabilitation; POST3).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
95
FSI intervention involves strengthening of the hip musculature combined with focused techniques emphasizing early initiation of hip muscle recruitment to stabilize the pelvis, integrating strength and movement pattern training to maximize functional recovery. The FSI program consists of therapeutic exercise in 3 domains: pelvic stability (PST) training, functional training (FT), and strength training (ST). PST includes early surgical-limb weight bearing and core muscle strengthening, progressively increasing in difficulty based on performance benchmarks and therapist monitoring. FT focuses on gait and stair climb exercise, progressing to higher level agility training. ST includes progressive, resistance exercise to improve lower extremity muscle strength. The ST exercises include use of weighted pulleys/weight-training machines. Therapists will determine an 8-rep max for muscle groups and weight will be increased by 10% every 2 weeks to maximize hypertrophy and strength gains.
Observed practice patterns from previous investigations and discussion with physical therapists indicate that patients receive rehabilitation services during the 2-3 day hospital stay after THA, but not routinely after hospital discharge. Yet, to control for attention and volume of rehabilitation for the FSI group, patients in the control group will attend outpatient physical therapy for 14 visits (40 minute sessions) over 8 weeks. This control program will mimic the typical postoperative experience for patients in our community, in which patients independently manage their activity. This program will focus on patient education, functional ADL training, and therapeutic exercise. However, the activities in the exercise domain will be limited to low load exercise such as isometric muscle exercise, range of motion (ROM), and flexibility activities. These activities are specifically designed to mirror usual care activity.
Rocky Mountain Regional VA Medical Center, Aurora, CO
Aurora, Colorado, United States
6 Minute Walk Test (6MW)
Patients will perform a 6MW test, which assesses how far a patient walks in 6 minutes. The 6MW test was chosen as the primary outcome because it captures performance over a period of time that best mimics community ambulation with activities of daily living. Higher numbers indicate better function. The 6MW test is reliable and valid in the post-THA population and can detect small changes in function after THA. 6MW will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in 6MW from baseline to intervention end-point (after 8 week intervention; POST2)
4 Meter Walk (4MW)
The 4MW test measures the time to walk 4 meters and has been used to generate gait speed values, which have been associated with morbidity and mortality in older adults. Higher numbers indicate better speed values. Participants will perform the 4MW with instructions to walk in their "normal, everyday pace." 4MW will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in 4MW from baseline to intervention end-point (after 8 week intervention; POST2)
30 Second Sit-to-stand (30 STS)
The 30 second sit-to-stand test assesses functional lower extremity strength and endurance, and has been validated and found reliable in older adults at various physical activity levels and physical independence levels. Higher numbers indicate better lower extremity strength and endurance. 30 STS will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in 30 STS from baseline to intervention end-point (after 8 week intervention; POST2)
Functional Gait Assessment (FGA)
Participants will also perform the FGA, which is a 10-item objective outcome measure designed to measure dynamic balance while walking in the presence of external demands, and will provide information on patients' stability before and after THA. The FGA has been shown to be a reliable and valid measure, effective in classifying fall risk in older adults and predicting unexplained falls. Scores range from 0-30, with higher scores indicating better functions. FGA will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
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Time frame: Change in FGA from baseline to intervention end-point (after 8 week intervention; POST2)
Isometric Strength
Isometric strength of the quadriceps and hip abductor muscles will be assessed on a handheld dynamometer. All strength testing will be performed in positions that minimize the risk of hip dislocation post-operatively, while still allowing for optimal trunk and pelvic stabilization. Isometric quadriceps strength testing will be performed in sitting at 0 hip flexion and 60 knee flexion. Isometric hip abduction strength testing will be performed in side lying at 0 flexion/extension and 0 hip abduction. Testing will include warm-up repetitions, followed by three separate maximal voluntary isometric contractions while receiving visual and verbal feedback. Strength will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in strength from baseline to intervention end-point (after 8 week intervention; POST2)
Modified Trendelenburg Test
Patients will complete hip abductor endurance testing using a static single-limb balance test,. This modified Trendelenburg test assesses neuromuscular control during single limb stance and indicates the ability of the lateral hip muscles to maintain pelvic control during closed-chain, functional tasks and therefore serves as a measure of hip abductor muscle endurance. This test will be performed using a high-speed motion-capture system to assess lateral pelvic tilt. Differences in length of time pelvic control is maintained will be analyzed from preoperative to postoperative assessments during the single-limb task on the surgical leg. Trendelenburg will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in Trendelenburg test from baseline to intervention end-point (after 8 week intervention; POST2)
Peak Internal Hip Abduction Moment
Surgical limb peak internal hip abduction moment will be calculated with 3-D instrumented motion analysis. Continuous internal hip abduction moments will be calculated during functional task performance using a standard inverse dynamics approach integrating kinematic and kinetic data using Visual 3D software (C-Motion, Germantown, MD). Peak internal hip moment during activity is a measurement of muscle activity during the task and provides insight to how muscles are activated during the task. Since the intervention exercise program targeted improving recruitment of the hip abductor moments during gait and other functional tasks, we calculated internal hip abduction moments. From the continuous hip moments, peak surgical limb internal hip abduction moments during the Loading Response phase of the stance period of the walking trials will be collected. Moments will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in moment from baseline to intervention end-point (after 8 week intervention; POST2)
ActiGraph
ActiGraph activity monitors assess physical activity (PA) using accelerometry, which allows objective evaluation of the relative volume (steps/day) and intensity (activity counts) of physical activity with high validity and reliability. Each participant will wear the ActiGraph for at least 4 days at all time points to assess average daily PA (steps/day). Higher number of steps indicates higher level of physical activity. PA will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in physical activity from baseline to intervention end-point (after 8 week intervention; POST2)
Veterans RAND 12-item Health Survey (VR-12)
The Veterans RAND (VR-12) is a reliable, self-report survey for assessing health-related quality of life. The questions in this survey correspond to seven different health domains: general health perceptions, physical functioning, role limitations due to physical and emotional problems, bodily pain, energy/fatigue levels, social functioning and mental health. Answers are summarized into two scores, a Physical Component Score (PCS) and a Mental Component Score (MCS) which then provides an important contrast between the respondents' physical and psychological health status. Each component score is summarized from 0 to 100, with a higher score indicating a better outcome. VR-12 scores will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in VR-12 from baseline to intervention end-point (after 8 week intervention; POST2)
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)
The WOMAC is a self-report questionnaire that assesses the impact of osteoarthritis on pain, stiffness, and disability. The WOMAC has been shown to be a valid, reliable, and responsive instrument often used in clinical trials. Scores range from 0-96, with higher scores indicating more pain, stiffness, and disability. WOMAC scores will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3).
Time frame: Change in WOMAC from baseline to intervention end-point (after 8 week intervention; POST2)
Patient Activation Measure (PAM)
The PAM survey assesses patient knowledge, skill, and confidence for self-management, as self-efficacy exhibits a positive relationship with preventive actions and health outcomes. The Continuous Score is a composite score of the available 10 items, ranging from 0-100, wherein a higher score indicates a higher activation (better outcomes). The PAM Level is the mean of the 4 Categorical Levels, wherein a higher score indicates a higher activation (better outcomes). Categorical Level 1: disengaged and overwhelmed; Categorical Level 2: becoming aware but still struggling; Categorical Level 3: taking action \& gaining control; Categorical Level 4: maintaining behaviors \& pushing further. Specific cut offs for each Categorical Level are unavailable, as scoring is proprietary.
Time frame: Assessed at baseline only
Patient Activation Measure (PAM) Categorical
The PAM survey assesses patient knowledge, skill, and confidence for self-management, as self-efficacy exhibits a positive relationship with preventive actions and health outcomes. The Categorical Levels are frequency distribution of the scores between 1-100, wherein a higher Categorical Level indicates a higher activation (better outcomes). Categorical Level 2: becoming aware but still struggling; Categorical Level 3: taking action \& gaining control; Categorical Level 4: maintaining behaviors \& pushing further. Specific cut offs for each Categorical Level are unavailable, as the scoring is proprietary.
Time frame: Assessed at baseline only
Motivation Scale
The motivation scales asks the participant "How motivated do you feel to participate in physical therapy?", and rating on a 0 (not at all motivated) to 10 (very motivated) scale. Higher scores indicate higher level of motivation.
Time frame: Quantification at Baseline