Effect of sensor location for modifying center of pressure during gait using haptic feedback in people with chronic ankle instability.

BACKGROUND: Gait retraining using haptic biofeedback medially shifts the center of pressure (COP) while walking in orthopedic populations. However, the ideal sensor location needed to effectively shift COP medially has not been identified in people with chronic ankle instability (CAI). RESEARCH QUESTIONS: Can a heel sensor location feasibly be employed in people with CAI without negatively altering kinematics? Does a heel sensor placement relative to the 5th metatarsal head (5MH) impact COP location while walking in people with CAI? METHODS: In this exploratory crossover study, 10 participants with CAI walked on a treadmill with vibration feedback for 10 minutes with a plantar pressure sensor under the heel and 5MH. Separate 2×2 repeated measures analyses of covariances (rmANCOVAs) were used to compare the averaged COP location and 3-D lower extremity kinematics from the first 10% of stance before and after training and between sensor locations. Baseline measures served as covariates to adjust for baseline differences. RESULTS: Feedback triggered by a heel sensor resulted in 40% of participants avoiding a heel strike. There were no significant main effects or interactions between time and sensor location on COP location when controlling for baseline COP (p>0.05). However, with the 5MH placement, participants displayed less ankle internal rotation(IR) (5MH/Heel: -4.12±0.00º/ -6.43±0.62º), less forefoot abduction (-4.29±0.00º/ -5.14±1.01º), more knee flexion (3.40±0.32º/ 0.14±0.57º), less knee external rotation (-10.95±0.00º/-11.24±1.48º), less hip extension (-0.20±0.00º/-1.42±1.05º), and less hip external rotation (3.12±0.00º/3.75±1.98º). SIGNIFICANCE: A 5MH location may be more feasible based on difficulties maintaining heel strike when the sensor was under the heel. While no sensor location was statistically better at changing the COP, the 5MH location decreased proximal transverse plane motions making participants' gait more like controls. Individual response variations support comprehensive lower extremity assessments and the need to identify responder profiles using sensory feedback in people with CAI.

Immediate effects of vibration biofeedback on ankle kinematics in people with chronic ankle instability.

BACKGROUND: People with chronic ankle instability are more inverted during initial contact and loading response which may increase the risk of subsequent ankle injuries. Vibration feedback gait retraining causes medial center of pressure shifts but its impact on ankle kinematics remains unknown. The purpose of this study was to understand kinematic ankle changes in people with chronic ankle instability following vibration feedback gait retraining. METHODS: Nineteen participants with chronic ankle instability walked with vibration feedback for 10 min on a treadmill and for one mile in the real-world. A vibration stimulus occurred at the lower leg when pressure under the 5th metatarsal exceeded a threshold. Three-dimensional kinematics of the ankle were recorded in the lab before and after training. Paired t-tests compared baseline and posttest ankle, hindfoot, and forefoot positions during initial contact and loading response for the lab and real-world conditions. FINDINGS: After lab training the ankle (mean difference:-1.68 ± 1.62°, effect size:0.95) and forefoot (mean difference:-1.68 ± 1.67°, effect size:0.92) were more abducted. After real-world training, the ankle (mean difference:-1.19 ± 2.12°, effect size:0.54) and forefoot (mean difference:-1.87 ± 3.00°, effect size:0.63) were more everted. Similarly the ankle (mean difference:-2.37 ± 4.79°, effect size:0.46) and forefoot (mean difference:-2.78 ± 4.91°, effect size:0.51) were more abducted after real-world training. INTERPRETATION: Vibration feedback decreases inversion and adduction during loading response. However, RW compared to lab training may have more beneficial frontal plane changes for people with chronic ankle instability.

Acute Vibration Feedback During Gait Reduces Mechanical Ankle Joint Loading in Chronic Ankle Instability Patients.

BACKGROUND: Individuals with chronic ankle instability (CAI) exhibit altered vertical ground reaction forces (vGRF), a laterally shifted center of pressure, and an inverted foot position during walking. These neuromechanical alterations are linked with altered ankle joint loading in this population. Vibration-based gait retraining improves center of pressure positioning but effects on neuromechanical variables influencing joint loading remains unknown. RESEARCH QUESTION: Do patients with CAI exhibit altered vGRF and ankle joint contact forces (JCF) after receiving a single session of vibration-based gait retraining? METHODS: Ten individuals with CAI underwent a single session of vibration-based gait retraining. Kinematic and kinetic data were collected during walking on an instrumental treadmill with force plates embedded in it. Following a baseline gait assessment without feedback, participants walked at a self-selected speed for 10 minutes while receiving feedback. Data was collected during an early (1 st and 2 nd minute) and late adaptation phase (9 th and 10 th minute) and, compared to baseline values. Impact and propulsive vGRF variables (i.e. peak, time to peak, and loading rate) were obtained. Musculoskeletal modeling was used to calculate ankle JCF variables (peak, impulse, and loading rate) during stance phase. RESULTS: Propulsive vGRF and ankle JCF outcomes were significantly reduced during the early and late adaptation phases (p ≤ 0.039). SIGNIFICANCE: These results indicate that vibration-based gait retraining can immediately reduce propulsive vGRF and ankle JCF and may represent a modality that could help restore appropriate ankle joint loading patterns in those with CAI.

Lateral Ankle Sprain and Subsequent Ankle Sprain Risk: A Systematic Review.

OBJECTIVE: To evaluate the evidence regarding the association between lateral ankle sprain (LAS) history and the subsequent LAS risk, as well as sex differences in the observed associations. DATA SOURCES: PubMed, CINAHL, and SPORTDiscus were searched through July 2020 for articles on LAS history and incidence during the study period. STUDY SELECTION: Studies were included if they were prospective in nature and the authors reported the number of participants with and those without a history of LAS at study initiation as well as the number of participants in each group who sustained an LAS during the investigation. DATA EXTRACTION: Data were study design parameters as well as the number of participants with and those without an LAS history and the number of subsequent LASs that occurred in both groups. Risk ratios (RRs) with 95% CIs compared the risk of LAS during the study period between those with and those without an LAS history for each investigation. DATA SYNTHESIS: A total of 19 studies involving 6567 patients were included. The follow-up periods ranged from 14 weeks to 2 years. Assessment scores indicated the studies were of moderate to high quality. A significantly higher risk of LAS during the study period was observed among those with a history of LAS in 10 of 15 studies (RR range = 1.29-6.06). Similar associations were seen in 4 of 6 studies of all-male samples (RR range = 1.38-8.65) and 1 of 4 studies with an all-female sample (RR = 4.28). CONCLUSIONS: Strong evidence indicates that a previous LAS increased the risk of a subsequent LAS injury. Men with a history of LAS appeared to be at a higher risk of sustaining a subsequent LAS, but women were not. However, further data are needed to draw definitive conclusions from the limited number of sex-specific studies.

The effect of laboratory and real world gait training with vibration feedback on center of pressure during gait in people with chronic ankle instability.

BACKGROUND: External feedback has can medially shift the center of pressure (COP) location in people with chronic ankle instability(CAI) during walking. However, previous modalities are restricted to controlled environments which limits motor learning. Vibration feedback during gait may maximize motor learning by allowing for training in the laboratory and real world (RW) but has not been investigated in those with CAI. RESEARCH QUESTION: Does vibration feedback change COP location in people with CAI following laboratory and RW training? METHODS: Nineteen CAI participants walked for 10 min on a treadmill (lab training) and a one mile loop on a sidewalk (RW training) with vibration feedback. When pressure under the 5th metatarsal exceeded a threshold, a vibration stimulus was applied to the lateral malleolus encouraging the participant to medially shift the COP. One minute baseline, posttest, and short term retention gait assessments were taken for each environment. The stance phase of gait was divided into 10 subphases and data were averaged within each subphase. Repeated measures ANOVAs were completed for each subphase to compare COP location over time. RESULTS: After lab based training the COP was more medial at posttest for the first 90 % of stance versus baseline (Mean differences (MD): -0.57 to -5.12 mm, p < 0.023). Relative to baseline, the COP remained more medial at retention from 20 to 90% of stance (MD: -1.69 to -4.40 mm, p < 0.049). For RW training, the COP was more medial at posttest for the first 70 % of stance versus baseline (MD: -4.24 to -8.27 mm, p < 0.017) and the first 60 % of stance at retention versus baseline (MD: -4.14 to -6.42 mm, p < 0.049). SIGNIFICANCE: Vibration feedback during laboratory and RW gait training has the ability to immediately shift the COP location medially and retain this shift for a short period in individuals with CAI.

Lateral ankle sprain increases subsequent ankle sprain risk: a systematic review.

OBJECTIVE: To evaluate the evidence surrounding the association between lateral ankle sprain (LAS) history and subsequent LAS risk, as well as sex-differences in the observed associations. DATA SOURCES: PubMed, CINAHL, and SPORTDiscus were searched through July 2020 for articles reporting LAS injury history and injury incidence during a study period. STUDY SELECTION: Studies were included if they were prospective in nature, reported the number of participants with and without a history of LAS at study initiation, and reported the number of participants from each group that sustained a LAS during the study period. DATA EXTRACTION: Data included study design parameters as well as the number of participants with and without a LAS history, and the number of subsequent LAS that occurred to both groups. Risk ratios (RR) with 95% confidence intervals (CI) compared the risk of LAS within the study period between those with and without a LAS history for each included investigation. DATA SYNTHESIS: Nineteen studies with a total of 6,567 patients were included. Follow-up periods ranged from 14 weeks to 2 years. Quality assessment scores indicate moderate to high quality studies were included. A significantly higher risk of LAS within the study period was observed among those with a history of LAS in 10 out of 15 studies (RR range=1.29-6.06). Similar associations were seen in four out of six studies that included an all-male sample (RR Range=1.38-8.65), and one out of four studies with an all-female sample (RR=4.28). CONCLUSION: There is strong evidence to support that a previous LAS increases the risk of a subsequent LAS injury. Males but not females with a history of a LAS appear to be at a higher risk of sustaining a subsequent LAS but further data are needed to draw definitive conclusions based on the limited number of sex specific studies.

Gait Biomechanics Following Taping and Bracing in Patients With Chronic Ankle Instability: A Critically Appraised Topic.

Clinical Scenario: Approximately 30% of all first-time patients with LAS develop chronic ankle instability (CAI). CAI-associated impairments are thought to contribute to aberrant gait biomechanics, which increase the risk of subsequent ankle sprains and the development of posttraumatic osteoarthritis. Alternative modalities should be considered to improve gait biomechanics as impairment-based rehabilitation does not impact gait. Taping and bracing have been shown to reduce the risk of recurrent ankle sprains; however, their effects on CAI-associated gait biomechanics remain unknown. Clinical Question: Do ankle taping and bracing modify gait biomechanics in those with CAI? Summary of Key Findings: Three case-control studies assessed taping and bracing applications including kinesiotape, athletic tape, a flexible brace, and a semirigid brace. Kinesiotape decreased excessive inversion in early stance, whereas athletic taping decreased excessive inversion and plantar flexion in the swing phase and limited tibial external rotation in terminal stance. The flexible and semirigid brace increased dorsiflexion range of motion, and the semirigid brace limited plantar flexion range of motion at toe-off. Clinical Bottom Line: Taping and bracing acutely alter gait biomechanics in those with CAI. Strength of Recommendation: There is limited quality evidence (grade B) that taping and bracing can immediately alter gait biomechanics in patients with CAI.