Osteoarthritis (OA) is a leading cause of disability worldwide that affects millions of Americans each year. Posttraumatic OA (PTOA) significantly impacts patients after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) with approximately 50% of patients developing PTOA within 20 years of injury or surgery. Knee joint mechanical loading measured via physical activity (i.e. daily steps) is insufficient in individuals after ACLR compared to uninjured individuals. Establishing the beneficial effects of physical activity to promote optimal free-living knee joint mechanical loading and improve knee joint health will aid in the development of cost-effective interventions that prevent PTOA and health burden of the disease.
Osteoarthritis (OA) is a leading cause of disability worldwide resulting in severe limitations in daily activities and chronic pain. It is estimated that 35% of posttraumatic OA (PTOA) cases occur after knee injuries and surgeries such as anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR). Optimal free-living mechanical loading, which refers to the forces acting on the knee caused by daily activities, plays an essential role in maintaining knee articular cartilage health. After ACLR, individuals take fewer steps per day as compared to uninjured controls. This results in insufficient free-living mechanical loading to joint tissues and is associated with early PTOA development. Adequate physical activity (PA) is recommended to help reduce risk of PTOA, but it is unclear how changes in PA acutely impact knee joint cartilage health. The overall objective of this pretest-posttest experimental pilot study is to determine how optimizing free-living mechanical loading through PA promotion improves cartilage composition in individuals who demonstrate insufficient free-living mechanical loading after ACLR. PA promotion will be delivered over 8 weeks using commercially available PA monitors and the patients' smartphone to provide daily personalized and achievable step goals to increase daily step counts to a level consistent with healthy PA participation. The hypothesis for aim 1 is that MRI markers of proteoglycan density associated with PTOA development will improve after 8-weeks of PA promotion exposure. Hypothesis for aim 2 is that greater changes in steps per day will be associated with improved proteoglycan density. Change in MRI markers of proteoglycan density and steps per day will be assessed using a pretest-posttest design in 8 adults who are 6 months to 5 years post-ACLR with insufficient mechanical loading (\<8,000 steps per day)24 and suboptimal quality of life (quality of life survey\<87.5). Outcomes will be collected before (pretest) and after (posttest) 8-weeks of PA promotion. For the PA promotion, participants will receive a text message each morning with a personalized, daily step count goal and a link used to confirm receipt of the goal. The preceding 10 days of step data will be rank ordered and the 60th percentile step count will be set as the goal for the next day. The proposed work is innovative, in that this study will use a novel combination of outcomes that will lead to unprecedented insight into the influence of PA promotion in mitigating early PTOA development.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
7
After enrolling, participants will be outfitted with a Fitbit Charge 2 activity monitor. The monitor will be worn during all waking hours, and compliance will be considered as a day with ≥ 1,000 steps. Participants will complete a 14-day "run-in" observation period while wearing the Fitbit but no PA promotion will occur. Individuals who are noncompliant during the "run in" period (\<10 days with \<1,000 steps) will be removed. Participants will receive a text message each morning with a personalized, daily step count goal and a link used to confirm receipt of the goal. The preceding 10 days of step data will be rank ordered and the 60th percentile step count will be set as the goal for the next day.
Fetzer Hall, University of North Carolina
Chapel Hill, North Carolina, United States
T1rho Relaxation Times in the Medial Femoral Condyle at Baseline
MRI marker of T1rho relaxation times of medial femoral articular cartilage (i.e proteoglycan density) at pre-intervention (baseline)
Time frame: pre-intervention (baseline)
T1rho Relaxation Times in the Medial Femoral Condyle Post-intervention
MRI marker of T1rho relaxation times of medial femoral articular cartilage (i.e proteoglycan density) at post-intervention (\~8 weeks)
Time frame: post-intervention (~8 weeks)
T1rho Relaxation Times in the Lateral Femoral Condyle at Baseline
MRI marker of T1rho relaxation times of lateral femoral articular cartilage (i.e., proteoglycan density) at pre-intervention (baseline)
Time frame: pre-intervention (baseline)
T1rho Relaxation Times in the Lateral Femoral Condyle Post-intervention
MRI marker of T1rho relaxation times of lateral femoral articular cartilage (i.e proteoglycan density) at post-intervention (\~8 weeks)
Time frame: post-intervention (~8 weeks)
T1rho Relaxation Times in the Medial Tibial Condyle at Baseline
MRI marker of T1rho relaxation times of medial tibial articular cartilage (i.e proteoglycan density) at pre-intervention (baseline)
Time frame: pre-intervention (baseline)
T1rho Relaxation Times in the Medial Tibial Condyle Post-intervention
MRI marker of T1rho relaxation times of medial tibial articular cartilage (i.e proteoglycan density) at post-intervention (\~8 weeks)
Time frame: post-intervention (~8 weeks)
T1rho Relaxation Times in the Lateral Tibial Condyle at Baseline
MRI marker of T1rho relaxation times of lateral tibial articular cartilage (i.e proteoglycan density) at pre-intervention (baseline)
Time frame: pre-intervention (baseline)
T1rho Relaxation Times in the Lateral Tibial Condyle Post-intervention
MRI marker of T1rho relaxation times of lateral tibial articular cartilage (i.e proteoglycan density) at post-intervention (\~8 weeks)
Time frame: post-intervention (~8 weeks)
Change in Daily Steps
Change in average steps per day over 7 day physical activity monitor wear pre-intervention (baseline) to approximately 8-weeks after physical activity promotion intervention
Time frame: pre-intervention (baseline), post-intervention (~8 weeks)
Change in T1rho Relaxation Times in the Medial Femoral Condyle
Change in MRI marker of T1rho relaxation times of medial femoral articular cartilage (i.e proteoglycan density) from pre-intervention (baseline) to approximately 8-weeks after physical activity promotion intervention
Time frame: pre-intervention (baseline), post-intervention (~8 weeks)
Change in T1rho Relaxation Times in the Medial Tibial Condyle
Change in MRI marker of T1rho relaxation times of medial tibial articular cartilage (i.e proteoglycan density) from pre-intervention (baseline) to approximately 8-weeks after physical activity promotion intervention
Time frame: pre-intervention (baseline), post-intervention (~8 weeks)
Change in T1rho Relaxation Times in the Lateral Femoral Condyle
change in MRI marker of T1rho relaxation times of lateral femoral articular cartilage (i.e proteoglycan density) from pre-intervention (baseline) to approximately 8-weeks after physical activity promotion intervention
Time frame: pre-intervention (baseline), post-intervention (~8 weeks)
Change in T1rho Relaxation Times in the Lateral Tibial Condyle
change in MRI marker of T1rho relaxation times of lateral tibial articular cartilage (i.e proteoglycan density) from pre-intervention (baseline) to approximately 8-weeks after physical activity promotion intervention
Time frame: pre-intervention (baseline), post-intervention (~8 weeks)
Knee Injury and Osteoarthritis Outcome Score Quality of Life Subscale
Knee injury Osteoarthritis Outcome Score (KOOS) Quality of Life subscale to measure knee-related quality of life at pre-intervention (baseline). A higher score indicates better knee-related quality of life. Min = 0 and Max = 100
Time frame: pre-intervention (baseline)
Knee Injury and Osteoarthritis Outcome Score Quality of Life Subscale
Knee injury Osteoarthritis Outcome Score Quality of Life subscale (KOOS) Quality of Life subscale to measure knee-related quality of life at post-intervention. A higher score indicates better knee-related quality of life. Min = 0 and Max = 100
Time frame: post-intervention (~8 weeks)
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