Validity and reliability of accelerations and orientations measured using wearable sensors during functional activities.

Wearable sensors may enable the assessment of movement in a real-world setting, but they are not yet a standard practice in the analysis of movement due to the unknown accuracy and reliability with respect to different functional activities. Here, we established the concurrent validity and test-retest reliability of accelerations and orientations measured using affordable novel sensors during squats, jumps, walking and stair ambulation. In this observational study, participants underwent three data collection sessions during one day. Accelerations and orientations from sacrum, thigh and shank were collected using these sensors and already validated gold-standard sensors as the criterion method. We assessed validity by comparing the similarity of signal waveforms with the Linear Fit Method and by comparing mean differences in range values with the Bland-Altman plots. Reliability was assessed by calculating interclass correlation coefficient and standard error of measurements of the range values. Concurrent validity was from fair to excellent in 91% of the cases for accelerations and in 84.4% for orientations. Test-retest reliability of accelerations was from fair to excellent in 97% of cases when the sensors were attached by a researcher, and in 84.4% of cases when the sensors were attached by participants. Test-retest reliability of orientations was from fair to excellent in 88.9% of cases when the sensors were attached by a researcher, and in 68.9% of cases when the sensors were attached by participants. In conclusion, the new affordable sensors provide accurate measures of accelerations and orientations during multiple functional activities in healthy adults. Reliability of the orientations may depend on the ability to replicate the same position of the sensor under test-retest conditions.

Applications of Wearable Technology in a Real-Life Setting in People with Knee Osteoarthritis: A Systematic Scoping Review.

With the growing number of people affected by osteoarthritis, wearable technology may enable the provision of care outside a traditional clinical setting and thus transform how healthcare is delivered for this patient group. Here, we mapped the available empirical evidence on the utilization of wearable technology in a real-world setting in people with knee osteoarthritis. From an analysis of 68 studies, we found that the use of accelerometers for physical activity assessment is the most prevalent mode of use of wearable technology in this population. We identify low technical complexity and cost, ability to connect with a healthcare professional, and consistency in the analysis of the data as the most critical facilitators for the feasibility of using wearable technology in a real-world setting. To fully realize the clinical potential of wearable technology for people with knee osteoarthritis, this review highlights the need for more research employing wearables for information sharing and treatment, increased inter-study consistency through standardization and improved reporting, and increased representation of vulnerable populations.

Minimal shoes improve stability and mobility in persons with a history of falls.

Postural and walking instabilities contribute to falls in older adults. Given that shoes affect human locomotor stability and that visual, cognitive and somatosensory systems deteriorate during aging, we aimed to: (1) compare the effects of footwear type on stability and mobility in persons with a history of falls, and (2) determine whether the effect of footwear type on stability is altered by the absence of visual input or by an additional cognitive load. Thirty participants performed standing and walking trials in three footwear conditions, i.e. conventional shoes, minimal shoes, and barefoot. The outcomes were: (1) postural stability (movement of the center of pressure during eyes open/closed), (2) walking stability (Margin of Stability during normal/dual-task walking), (3) mobility (the Timed Up and Go test and the Star Excursion Balance test), and (4) perceptions of the shoes (Monitor Orthopaedic Shoes questionnaire). Participants were more stable during standing and walking in minimal shoes than in conventional shoes, independent of visual or walking condition. Minimal shoes were more beneficial for mobility than conventional shoes and barefoot. This study supports the need for longitudinal studies investigating whether minimal footwear is more beneficial for fall prevention in older people than conventional footwear.

Minimal footwear improves stability and physical function in middle-aged and older people compared to conventional shoes.

BACKGROUND: Effects of minimal shoes on stability and physical function in older people are under-researched. No studies have systematically explored effects of a range of minimal footwear features on these factors in older people. METHODS: A within-participant repeated-measures design was used. Participants were subjected to thirteen footwear conditions: (i) barefoot, (ii) a conventional shoe, (iii) a control minimal shoe, (iv-xiii) minimal shoes differing from the control minimal shoe by one design feature. The outcomes were: (i) postural stability expressed with movement of the center of pressure (CoP) during standing (ii) dynamic stability expressed with the CoP movement during walking, (iv) physical function assessed with the Timed Up and Go test (TUG), and (iv) perceptions of footwear assessed with the Monitor Orthopaedic Shoes questionnaire. Linear Mixed Models were applied for statistical analyses. FINDINGS: Twenty-two people participated in the study. Compared to the conventional shoe, participants: (i) were more stable during standing and walking in the majority of minimal shoes, and (ii) completed the TUG test faster when wearing the minimal shoe with wider sole. Compared to the control minimal shoe, participants: (i) completed the TUG test faster when wearing the minimal shoe with wider sole; and (ii) perceived features such as a split toe and a higher ankle collar as less fashionable and wearable. INTERPRETATION: Wearing minimal shoes might be more beneficial for stability and physical function in older adults than wearing conventional shoes. The results will be highly valuable for the design of minimal footwear for older adults.

Decreased Pain and Improved Dynamic Knee Instability Mediate the Beneficial Effect of Wearing a Soft Knee Brace on Activity Limitations in Patients With Knee Osteoarthritis.

OBJECTIVE: To evaluate whether improvement of proprioception, pain, or dynamic knee instability mediates the effect of wearing a soft knee brace on activity limitations in patients with knee osteoarthritis (OA). METHODS: We conducted an analysis of data for 44 patients with knee OA who were enrolled in a laboratory-based trial evaluating the effect of wearing a commercially available soft knee brace. Activity limitations were assessed with the 10-meter walk test and the Get Up and Go test. Knee joint proprioception was assessed by an active joint position sense test; pain was assessed on a numeric rating scale (NRS) (range 0-10); pressure pain threshold (PPT) was assessed with a hand-held pressure algometer; dynamic knee instability was expressed by the perturbation response, i.e., a measure reflecting a deviation in mean knee varus-valgus angle after a controlled mechanical perturbation on a treadmill, with respect to level walking. Mediation analysis was conducted using the product of coefficients approach. Confidence intervals were calculated with a bootstrap procedure. RESULTS: A decrease in pain (scored on an NRS) and a decrease in dynamic knee instability mediated the effect of wearing a soft knee brace on the reduction of activity limitations (P < 0.05), while changes in proprioception and PPT did not mediate this effect (P > 0.05). CONCLUSION: This study shows that decreased pain and reduced dynamic knee instability are pathways by which wearing a soft knee brace decreases activity limitations in patients with knee OA.

The immediate effect of a soft knee brace on dynamic knee instability in persons with knee osteoarthritis.

Objectives: Wearing a soft knee brace has been shown to reduce self-reported knee instability in persons with knee OA. There is a need to assess whether a soft knee brace has a beneficial effect on objectively assessed dynamic knee instability as well. The aims of the study were to evaluate the effect of a soft knee brace on objectively assessed dynamic knee instability and to assess the difference in effect between a non-tight and a tight soft knee brace in persons with knee OA. Methods: Thirty-eight persons with knee OA and self-reported knee instability participated in a laboratory study. A within-subject design was used comparing no brace vs brace and comparing a non-tight vs a tight brace. The primary outcome measure was dynamic knee instability, expressed by the perturbation response (PR). The PR reflects deviation in the mean knee varus-valgus angle during level walking after a controlled mechanical perturbation. Linear mixed-effect model analysis was used to evaluate the effect of a brace on dynamic knee instability. Results: Wearing a brace significantly reduced the PR compared with not wearing a brace (B = -0.16, P = 0.01). There was no difference between a non-tight and a tight brace (B = -0.03, P = 0.60). Conclusion: This study is the first to report that wearing a soft knee brace reduces objectively assessed dynamic knee instability in persons with knee OA. Wearing a soft brace results in an objective improvement of knee instability beyond subjectively reported improvement. Trial registration: Nederlands Trial register (trialregister.nl) NTR6363.

Proprioception mediates the association between systemic inflammation and muscle weakness in patients with knee osteoarthritis: Results from the Amsterdam Osteoarthritis cohort.

OBJECTIVES: To determine whether systemic inflammation is associated with poor proprioception; to confirm that systemic inflammation is associated with muscle weakness; and to determine whether poor proprioception mediates the association between systemic inflammation and muscle weakness in knee osteoarthritis. DESIGN: Cross-sectional study. SUBJECTS: A total of 689 participants with knee osteoarthritis from the Amsterdam Osteoarthritis (AMS-OA) cohort. METHODS: Systemic inflammation was assessed by erythrocyte sedimentation rate, knee proprioception by determining the joint motion detection threshold, and muscle strength with an isokinetic dynamometer. Linear regression models were used to estimate direct associations between systemic inflammation, proprioception and muscle strength, and the indirect association (mediation) between systemic inflammation and muscle strength via proprioception adjusted for potential confounders. RESULTS: Higher erythrocyte sedimentation rates were associated with poor proprioception (p = 0.022). Poor proprioception (p < 0.001) and higher erythrocyte sedimentation rates (p < 0.001) were associated with muscle weakness. Poor proprio-ception mediated the association between systemic inflammation and muscle weakness (p = 0.035). CONCLUSION: Results suggest that systemic inflammation is associated with poor proprioception in knee osteoarthritis. Poor proprioception may be a path-way through which systemic inflammation is associated with muscle weakness in patients with knee osteoarthritis.

Effect of Soft Braces on Pain and Physical Function in Patients With Knee Osteoarthritis: Systematic Review With Meta-Analyses.

OBJECTIVES: To systematically review and synthesize the effects of soft braces on pain and on self-reported and performance-based physical function in patients with knee osteoarthritis. DATA SOURCES: The following electronic databases were searched from inception to April 20, 2016: The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, CINAHL, SPORTDiscus, Web of Science, and PEDro. STUDY SELECTION: Randomized controlled trials (RCTs) and nonrandomized controlled trials (non-RCTs), such as controlled clinical trials, crossover studies, and case-control studies, were included. Two reviewers independently screened articles and determined inclusion through predefined criteria. DATA EXTRACTION: Data related to participant demographics, study design and methods, interventions, and outcomes, including numerical means and SDs, were extracted by 1 reviewer. Methodological quality assessment was independently performed by 2 reviewers. DATA SYNTHESIS: Eleven studies were identified, including 6 RCTs and 5 non-RCTs. The methodological quality of included RCTs was low. There was a moderate improvement in pain (standardized mean difference [SMD]=.52; 95% confidence interval [CI], .14-.89; P=.007; 284 participants) in favor of wearing a brace compared with not wearing a brace for the immediate, within-group comparison. There was a moderate improvement in pain (SMD=.61; 95% CI, .33-.89; P<.001; 206 participants) and a small to moderate improvement in self-reported physical function (SMD=.39; 95% CI, .11-.67; P=.006; 206 participants) in favor of patients receiving a soft brace versus standard care for the prolonged effect, between-group comparison. CONCLUSIONS: Currently available evidence indicates that soft braces have moderate effects on pain and small to moderate effects on self-reported physical function in knee osteoarthritis. These findings highlight the importance of soft braces as a technique to improve pain and physical function in both the short- and long-term. Additional high-quality studies are warranted to improve confidence in the findings.

The immediate effect of a soft knee brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence in patients with knee osteoarthritis.

BACKGROUND: We aimed to (i) evaluate the immediate effect of a soft knee brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence, and (ii) to assess the difference in effect between a non-tight and a tight soft brace in patients with knee osteoarthritis (OA). METHODS: Forty-four patients with knee OA and self-reported knee instability participated in the single-session, laboratory, experimental study. A within-subject design was used, comparing a soft brace with no brace, and comparing a non-tight with a tight soft brace. The outcome measures were pain, self-reported knee instability and knee confidence during level and perturbed walking on the treadmill and activity limitations (10-m walk test and the get up and go (GUG) test). Linear mixed-effect model analysis for continuous outcomes and logistic generalized estimating equations for categorical outcomes were used to evaluate the effect of wearing a soft brace. RESULTS: Wearing a soft brace significantly reduced pain during level walking (B - 0.60, P = 0.001) and perturbed walking (B - 0.80, P < 0.001), reduced the time to complete the 10-m walk (B - 0.23, P < 0.001) and the GUG tests (B - 0.23, P = 0.004), reduced self-reported knee instability during level walking (OR 0.41, P = 0.002) and perturbed walking (OR 0.36, P < 0.001), and reduced lack of confidence in the knees during level walking (OR 0.45, P < 0.001) and perturbed walking (OR 0.56, P < 0.001), compared with not wearing a soft brace. There was no difference in effects between a non-tight and tight brace, except for the 10-m walk test. Wearing a tight brace significantly reduced the time to complete the 10-m walk test in comparison with wearing a non-tight brace (B - 0.11, P = 0.03). CONCLUSION: The results of this study indicate that a soft brace is an efficacious intervention targeting pain, activity limitations, self-reported knee instability, and knee confidence in the immediate term in patients with knee OA. Further studies are needed evaluating the mode of action based on exerted pressure, and on the generalization to functioning in daily life. TRIAL REGISTRATION: trialregister.nl, NTR6363 . Retrospectively registered on 15 May 2017.