The purpose of this study is to examine the pre-post effects of a single ZILRETTA knee injection on physiological measures of self-reported pain and disability, physical performance, and physical activity in individuals with knee osteoarthritis (OA). The investigators will recruit 35 symptomatic knee OA patients for this study. All data will be collected prior to injection (baseline), as well as at 4 (post 1) and 8-week follow-ups (post 2).
Individuals with knee osteoarthritis (OA) demonstrate significant physical disability which leads to diminished physical activity, a lesser quality of life, as well as a higher risk of inactivity related comorbidities including mortality. This is thought to be caused by an inability to voluntarily activate your quadriceps muscle due, in part, to knee joint swelling and joint-related pain. Incomplete muscle activation causes quadriceps weakness. Individuals with quadriceps weakness exhibit changes in their walking biomechanics which is associated with diminished physical function and lesser physical activity in those with knee OA. Therefore, it is critical to develop interventions that target mechanisms causing decreased quadriceps activation in order to restore optimal walking biomechanics and improve physical activity. The ZILRETTA knee injection is an FDA approved, extended release corticosteroid for in patients with knee osteoarthritis and has been shown to reduced knee pain for 3 months in approximately 70% of patients. Currently, there are no studies that have examined ZILRETTA's objective effectiveness on physical activity, biomechanics, and performance tests in patients who have received an injection. The overall purpose of the current study is to examine the effect of a ZILRETTA knee injection on functional and performance tests including quadriceps neuromuscular activation, quadriceps strength, walking gait biomechanics, and a battery of physical performance outcomes at 4 and 8-weeks following injection in 35 individuals with knee OA.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
35
A single ZILRETTA® (triamcinolone acetonide extended-release injectable suspension) intra-articular knee injection.
MOTION Science Institute
Chapel Hill, North Carolina, United States
Percentage Change in Mean Maximal Quadriceps Strength as Measured by the Maximal Isometric Voluntary Contractions Normalized to Body Weight from Baseline to the 8-week follow-up.
Quadriceps strength was measured in Newton Meters normalized to body weight of the individuals. Strength was assessed in 90 degrees of knee flexion.
Time frame: Baseline and 8-week follow-up
Percentage Change in Mean Voluntary Quadriceps Activation as Measured by the Central Activation Ratio Expressed as a Percent of Full Activation from Baseline to the 8-week follow-up.
The investigators assessed voluntary quadriceps central activation ratio as a representative variable of lower extremity neuromuscular activation using the supra imposition technique. Quadriceps central activation ratio has been demonstrated to be significantly decreased in knee osteoarthritis (OA) compared to healthy, matched controls, and the investigators have reported acceptable measurement reliability (ICC2,k = 0.85)
Time frame: Baseline and 8-week follow-up
Percentage Change in Mean Knee Flexion Angle During Walking Gait Measured in Degrees of Knee Flexion from Baseline to the 8-week follow-up.
The peak Knee Flexion Angle was calculated using using inverse dynamics calculations in the first 50% of the stance phase of gait and during self selected gait speed.
Time frame: Baseline and 8-week follow-up
Percentage Change in Mean Internal Knee Extension Moment During Walking Gait Measured in Nm/ Body Weight*m from Baseline to the 8-week follow-up.
The peak internal knee extension moment was calculated using using inverse dynamics calculations in the first 50% of the stance phase of gait and normalized to the Body Weight\* height (m) of the individual during self selected gait speed.
Time frame: Baseline and 8-week follow-up
Percentage Change in Mean of Self-reported Disability Score as Measured by the Western Ontario and McMasters Universities Index from Baseline to the 8-week follow-up.
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The Western Ontario and McMasters Universities Index is reliable and valid measure of self reported disability. The physical function consists of 17 items and asks about the magnitude of difficulty when ascending and descending stairs, rising from sitting, standing, bending, walking, getting in / out of a car, shopping, putting on and taking off socks, rising from bed, lying in bed, getting in and out of the bath, sitting, getting on and off the toilet, completing heavy household duties, and completing light household duties. Each item is presented in a 5 point Likert-type format and uses the following descriptors for possible answer choices none, mild moderate, severe, and extreme. Each descriptor corresponds to an ordinal scale of 0-4. The scores are summed for the items in each subscale, with total possible ranges as 0-68. Higher scores on the WOMAC indicate greater amounts of functional limitations.
Time frame: Baseline and 8-week follow-up
Percentage Change in mean of self-reported Disability Score as Measured by the Knee Injury and Osteoarthritis Outcome Score from Baseline to the 8-week follow-up.
The Knee Injury and Osteoarthritis Outcomes Score (KOOS) consists of five subscales: Pain (9 items), Symptoms (7 items), Function in Activities of Daily Living (17 items), Function in Sport and Recreation (5 items) and Knee Related Quality of Life (4 items). Each item is presented in a 5 point Likert-type format that ranges from 0 (no problems) to 4 (extreme problems). Totals from each subscale are transformed to a 0-100 score. Lower scores on the KOOS indicate greater amounts of functional limitations.
Time frame: Baseline and 8-week follow-up
Percentage Change in Physical Activity Scale for the Elderly from baseline to the 8-week follow-up.
Physical Activity Scale for the Elderly (PASE) scores are calculated from weights and frequency values for each of 12 types of activity. Responses to the first question about sitting activities are not scored. The scale is continuous with higher scores indicating greater physical activity.
Time frame: Baseline and 8-week follow-up
Percentage Change in 30-s chair-stand test from Baseline to the 8-week follow-up.
The number of times that an individual can sit and stand in 30 seconds.
Time frame: Baseline and 8-week follow-up
Percentage Change in 20 meter fast-paced walk test from Baseline to the 8-week follow-up.
The investigators will time the amount of seconds it takes to walk 20 meters.
Time frame: Baseline and 8-week follow-up
Percentage Change in Stair-climb test from Baseline to the 8-week follow-up.
The investigators will time the amount of seconds it takes to walk up and down a flight of stairs.
Time frame: Baseline and 8-week follow-up
The percentage change in steps per day from Baseline to the 8-week follow-up.
Physical activity will be measured in the form of steps per day using an ActiGraph accelerometer. Participants will wear the ActiGraph for 7 days following each testing session.
Time frame: Baseline and 8-week follow-up