Improving Rehabilitation Outcomes After Total Hip Arthroplasty

Study Overview
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Brief Summary
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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.

Detailed Description
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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).

Official Title
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Improving Rehabilitation Outcomes After Total Hip Arthroplasty

Conditions
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Total Hip Arthroplasty, Osteoarthritis

Intervention / Treatment
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* Behavioral: Functional Strength Integration (FSI)
* Behavioral: Control Group (CON)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI less than or equal to 40 Receiving unilateral primary total hip arthroplasty for osteoarthritis Exclusion Criteria: Severe contralateral leg OA (>= 5/10 pain with stair climbing) Other unstable orthopaedic conditions that limit function Neurological or pulmonary problems that severely limit function Uncontrolled hypertension or diabetes Use of illegal substances

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Functional Strength Integration (FSI)<br>Progressive strength training exercise, specific functional activity to improve pelvic stability and core muscle strength | Behavioral: Functional Strength Integration (FSI)<br>* 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.<br>|
| Active Comparator: Control Group (CON)<br>Usual care, continuing education on postsurgical precautions | Behavioral: Control Group (CON)<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. 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). | Change in 6MW from baseline to intervention end-point (after 8 week intervention; POST2) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. 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). | 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. 30 STS will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3). | 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. FGA will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3). | 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). | 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 timed, 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 will be analyzed in pelvic tilt angles 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). | 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). 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). | 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). PA will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3). | Change in physical activity from baseline to intervention end-point (after 8 week intervention; POST2) | 
| Veterans RAND 12-item health survey (VR-12) | The VR-12 is a reliable, self-report survey for assessing health-related quality of life. VR-12 scores will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3). | 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. WOMAC scores will also be assessed at mid-intervention (POST1, 4 weeks) and 26-week evaluation (POST3). | 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. | 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. | Quantification at POST1 (after 4 weeks intervention) & POST 2 (after 8 weeks intervention) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Functional strength integration, Rehabilitation, Hip arthroplasty, Physical function, Muscle performance, Movement compensations