People with chronic ankle instability (CAI) demonstrate altered gait or walking mechanics which cause people to walk on the outside of their foot and increases the risk of additional ankle sprains, abnormal cartilage strain, and early joint degeneration. Evidence indicates that common treatments for CAI do not impact gait, leaving unresolved impairments that can lead to lifelong disability. Recent lab-based gait retraining with visual and auditory feedback has immediately improved walking mechanics. However, real-world training is hypothesized to generate long-term changes by incorporating short, frequent training sessions over a variety of surfaces. These are key training parameters to produce lasting change. Pilot data using real-world vibration feedback (RW-VF) suggest that a single session immediately improves walking mechanics with changes lasting for up to 5 minutes. Despite promising initial results, there remains a critical need to determine the impact of multiple RW-VF sessions as an initial step to developing a protocol capable of long-term improvements. The purpose of this proposal is to determine the extent to which 2-weeks of RW-VF restores gait biomechanics in those with CAI. Twenty people with CAI will be enrolled and complete a two-week gait retraining protocol with vibration feedback. Walking mechanics before, immediately after, and 1 week and 4 weeks following the training will be compared. These contributions can be significant as positive results will support a paradigm shift in treatments for people with CAI and lay the foundation for large scale clinical trials aimed at optimizing long term gains. The outcomes of future research have the potential to advance evidenced based rehabilitation interventions not only for people with CAI but also for people who have sustained a variety of musculoskeletal injuries as there is strong evidence that other lower extremity pathologies cause lifelong limitations, including changes in walking mechanics which lead to degenerative changes to other joints.
Background: There are 3.1 million lateral ankle sprains in the United States per year, of which about 40% will develop persistent limitations leading to chronic ankle instability (CAI). People with CAI demonstrate altered walking gait mechanics including increased inversion (ie: the foot rolling outward) and a lateral shift in the location of the center of pressure (COP) under the foot. These changes cause people to walk on the outside of their foot and increases the risk for additional ankle sprains, abnormal cartilage strain, and early post traumatic ankle arthritis (PTOA). Evidence indicates that common treatments for CAI do not impact gait, leaving unresolved impairments that can lead to lifelong disability. Recently walking with novel sensory feedback techniques (visual, auditory, and visual stimuli) has immediately improved walking mechanics during laboratory training. However, real-world (RW) training is hypothesized to generate long-term changes by incorporating short, frequent training sessions over a variety of surfaces which are key training parameters to produce lasting change. Vibration feedback (VF) is currently the only tool capable of being deployed in the real world. Recent pilot data suggest that a single VF training session in the RW immediately improves ankle and COP position with changes lasting for up to 5 minutes. Despite these promising initial results, there remains a critical need to determine the impact of multiple real-word vibration feedback (RW-VF) sessions as an initial step to developing a protocol capable of long-term improvements. Purpose: The purpose of this proposal is to examine the effectiveness of a new treatment approach by determining the extent to which 2-weeks of RW-VF restores gait biomechanics in those with CAI. Design: Cohort Study Methods: Kinematic and kinetic data will be captured from 20 participants with CAI at two baseline training sessions within 48 hours of each other (B1 and B2) while the participant walks on an instrumented treadmill. These data will be used to calculate the minimal detectable change (MDC), which is the stability of the walking measures. Following B2, participants will be fitted with the VF tool and complete the first of six training sessions. During training sessions, participants will walk six standardized but unique 1-mile RW routes with VF within a two-week time period. The order of the routes will be determined by a random number generator. Three additional biomechanical walking assessments will be completed within 72 hours of (P-2), one week following the final training (F-1), and 4 weeks following the final training (F-4). Data Analysis: The primary analysis will determine the impact of RW-VF on COP location during the stance phase of walking in people with CAI. COP location will be compared before and after treatment (B1:P-2) using paired t-tests to determine the immediate impact of RW-VF training. The change between B1 and P-2 will be compared to the MDC to rule out measurement error. Next, COP location between B1 and F-1, and B1 and F-4 will be calculated to determine the extent to which the COP change is retained and compared to the MDC to rule out measurement error. Finally, COP data from posttest and retention timepoints will be compared to a database of walking biomechanics data from healthy controls using independent t-tests to determine similarities between people with and without CAI following training. The secondary analysis will repeat the primary using ankle position in the frontal plane (inversion/ eversion) during stance. Significance: These contributions have the potential to be significant because positive results will support a paradigm shift in treatments for people with CAI. Positive results will also lay the foundation for large scale clinical trials comparing the current standard of care to the standard of care with the addition of RW-VF training to optimize long term gains. The outcomes of future research have the potential to advance evidenced based rehabilitation interventions not only for people with CAI but also for people who have sustained a variety of musculoskeletal injuries as there is strong evidence that other lower extremity pathologies cause lifelong limitations, including changes in walking mechanics which lead to degenerative changes to other joints.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
20
Participants will walk with a vibration feedback tool attached to their shoelaces. A small force sensing resistor is taped to the foot bed of the shoe under the lateral foot and a vibration motor is placed over the outside of the ankle with a strap. When a participant walks on the outside of their foot, they will exceed the pressure threshold and activate the feedback which signifies an incorrect foot placement. The feedback is intended to prompt a correct foot placement on the subsequent step. Participants will use the same feedback tool for 6 real world training sessions.
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
Immediate and retained changes in the center of pressure location under the foot at initial contact within the chronic ankle instability group in response to 2-weeks of RWVF gait retraining.
The location of the center of pressure (COP) under the foot will be collected while participants walk for 1-minute on an instrumented treadmill at each assessment in this repeated measures study (baseline, P-2, F-1, F-4). Data from each stance phase of walking will be divided into 10 equal parts each representing 10% of stance and averaged across all steps. Subphase 1 of the data will be used for the primary outcome as it represents initial contact of gait.
Time frame: COP location during walking will be measured at baseline, within 72 hours of completing the intervention (P-2), 1 week after the intervention (F-1), 1 month after the intervention (F-4).
Immediate and retained changes in the center of pressure location under the foot from 20% to 100% of the walking stance phase within the chronic ankle instability group in response to 2-weeks of RWVF gait retraining.
The location of the COP under the foot will be collected while participants walk for 1-minute on an instrumented treadmill at each assessment in this repeated measures study (baseline, P-2, F-1, F-4). Data from each stance phase of walking will be divided into 10 equal parts each representing 10% of stance and averaged across all steps. Subphases 2-10 of the data will be used for this secondary outcome.
Time frame: COP location during walking will be measured at baseline, within 72 hours of completing the intervention (P-2), 1 week after the intervention (F-1), 1 month after the intervention (F-4).
Differences between the COP location in people with CAI following 2-weeks of RWVF gait retraining and the COP location in healthy controls.
The location of the COP under the foot will be collected while CAI participants walk for 1-minute on an instrumented treadmill following 2-weeks of RWVF gait retraining (P-2). Previously, data were collected during 1-minute of walking on an instrumented treadmill from a healthy control cohort. Data from each stance phase of walking from both groups will be divided into 10 equal parts each representing 10% of stance and averaged across all steps. Subphases 1-10 of the data will be used for this secondary outcome to compare the COP location between groups.
Time frame: The COP location during walking will be measured following 2-weeks of training (P-2) in the CAI cohort and compared to pre-collected, de-identified healthy control data from a single session.
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