Development and Functional Testing of an Unloading Concept for Knee Osteoarthritis Patients: A Pilot Study.

This paper presents a knee brace design that applies an extension moment to unload the muscles in stance phase during gait, and thereby the knee, as alternative to conventional valgus braces for knee osteoarthritis patients. The concept was tested on one healthy subject during normal gait with a prototype, which was designed to activate and deactivate in order to apply the extension moment in the stance phase only and hereby avoid any interference during the swing phase. Electromyography measurements and musculoskeletal models were used to evaluate the brace effects on muscle activation and knee compressive forces, respectively. Simulations predicted an ideal reduction of up to 36%, whereas experimental tests revealed a reduction of up to 24% with the current prototype. The prototype brace also reduced the knee joint force impulse up to 9% and electromyography (EMG) peak signal of the vasti muscles with up to 19%. Due to these reductions on a healthy subject, this bracing approach seems promising for reducing knee loads during normal gait. However, further clinical experiments on knee osteoarthritis patients are required to evaluate the effect on both pain and disease progression.

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.

Embracing additive manufacture: implications for foot and ankle orthosis design.

BACKGROUND: The design of foot and ankle orthoses is currently limited by the methods used to fabricate the devices, particularly in terms of geometric freedom and potential to include innovative new features. Additive manufacturing (AM) technologies, where objects are constructed via a series of sub-millimetre layers of a substrate material, may present the opportunity to overcome these limitations and allow novel devices to be produced that are highly personalised for the individual, both in terms of fit and functionality.Two novel devices, a foot orthosis (FO) designed to include adjustable elements to relieve pressure at the metatarsal heads, and an ankle foot orthosis (AFO) designed to have adjustable stiffness levels in the sagittal plane, were developed and fabricated using AM. The devices were then tested on a healthy participant to determine if the intended biomechanical modes of action were achieved. RESULTS: The adjustable, pressure relieving FO was found to be able to significantly reduce pressure under the targeted metatarsal heads. The AFO was shown to have distinct effects on ankle kinematics which could be varied by adjusting the stiffness level of the device. CONCLUSIONS: The results presented here demonstrate the potential design freedom made available by AM, and suggest that it may allow novel personalised orthotic devices to be produced which are beyond the current state of the art.

Correction: Measurements agreement between low-cost and high-level handheld 3D scanners to scan the knee for designing a 3D printed knee brace.

[This corrects the article DOI: 10.1371/journal.pone.0190585.].

Measurements agreement between low-cost and high-level handheld 3D scanners to scan the knee for designing a 3D printed knee brace.

Use of additive manufacturing is growing rapidly in the orthotics field. This technology allows orthotics to be designed directly on digital scans of limbs. However, little information is available about scanners and 3D scans. The aim of this study is to look at the agreement between manual measurements, high-level and low-cost handheld 3D scanners. We took two manual measurements and three 3D scans with each scanner from 14 lower limbs. The lower limbs were divided into 17 sections of 30mm each from 180mm above the mid-patella to 300mm below. Time to record and to process the three 3D scans for scanners methods were compared with Student t-test while Bland-Altman plots were used to study agreement between circumferences of each section from the three methods. The record time was 97s shorter with high-level scanner than with the low-cost (p = .02) while the process time was nine times quicker with the low-cost scanner (p < .01). An overestimation of 2.5mm was found in high-level scanner compared to manual measurement, but with a better repeatability between measurements. The low-cost scanner tended to overestimate the circumferences from 0.1% to 1.5%, overestimation being greater for smaller circumferences. In conclusion, 3D scanners provide more information about the shape of the lower limb, but the reliability depends on the 3D scanner and the size of the scanned segment. Low-cost scanners could be useful for clinicians because of the simple and fast process, but attention should be focused on accuracy, which depends on the scanned body segment.

Personalized foot orthoses with embedded temperature sensing: Proof of concept and relationship with activity.

Plantar foot surface temperature has been identified as a clinically relevant physiological variable. Embedding sensors in foot orthoses (FOs) may allow long term monitoring of these temperatures, with compliance via the detection of periods of activity being a potential clinical utilization. This study aimed to test novel designs for FOs with embedded sensing that were produced via additive manufacturing and determine if foot temperature measurements could be used to detect periods of increased activity. FOs with embedded temperature sensors were developed and tested in 10 healthy participants over four day wear periods. Activity monitoring was used to estimate energy expenditure during testing. A threshold-based algorithm was developed to identify time periods of high activity from foot temperature data. Group differences in estimated energy expenditure between time periods below and above the threshold were significant in both the training and validation sets (p<0.001). Significant differences were also seen at individual participant level (p<0.001 in all cases). These results demonstrate the feasibility of using FOs with embedded sensing to monitor plantar surface foot temperatures during normal daily activities and for extended periods and show that periods of increased activity can be identified using foot temperature data.

Gait assessment during the initial fitting of customized selective laser sintering ankle foot orthoses in subjects with drop foot.

BACKGROUND: Recently, additive fabrication has been proposed as a feasible engineering method for manufacturing of customized ankle foot orthoses (AFOs). Consequently, studies on safety, comfort and effectiveness are now carried out to assess the performance of such devices. OBJECTIVE: Evaluate the clinical performance of customized (selective laser sintering) SLS-AFOs on eight subjects with unilateral drop foot gait and compare to clinically accepted (polypropylene) PP-AFOs. STUDY DESIGN: Active control trial. METHODS: For each subject two customized AFOs were fabricated: one SLS-AFO manufactured following an additive fabrication framework and one thermoplastic PP-AFO manufactured according to the traditional handcraft method. Clinical performance of both AFOs was evaluated during gait analysis. RESULTS: A significant beneficial effect of both custom-moulded PP-AFO and customized SLS-AFO in terms of spatial temporal gait parameters and ankle kinematic parameters compared to barefoot gait of adults with drop foot gait are observed. No statistically significant difference between the effect of PP-AFO and of SLS-AFO was found in terms of spatial temporal gait parameters and ankle kinematic parameters. CONCLUSION: AFOs manufactured through the SLS technique show performances that are at least equivalent to the handcrafted PP-AFOs commonly prescribed in current clinical practice. Clinical relevance Manufacturing personalized AFOs with selective laser sintering (SLS) in an automated production process results in decreased production time and guarantees the consistency of shape and functional characteristics over different production time points compared to the traditional manufacturing process. Moreover, it reduces the dependency of the appliance on the experience and craftsmanship of the orthopaedic technician.

Mass customization of foot orthoses for rheumatoid arthritis using selective laser sintering.

Rheumatoid arthritis is an inflammatory joint disease that can lead to pain, stiffness, and deformity, often with marked involvement of the small joints of the foot and ankle. Orthotic devices are commonly prescribed for this condition to lessen symptoms and improve function and mobility, and customized devices are most effective. The work reported in this paper has examined the feasibility of using an additive manufacturing-based approach to manufacture customized orthoses. In order to test feasibility, orthoses have been manufactured using the additive manufacturing technology of selective laser sintering, and have been evaluated through a small-scale patient trial (n = 7). The trial indicated that these orthoses performed as well as the patients' current prescribed customized devices in terms of the observed gait and subjective evaluation of fit and comfort. It is concluded that the feasibility of the additive manufacturing approach has been demonstrated, and further development of a mass customization system to deliver orthoses, together with exploitation of the design freedom offered by the manufacturing method, will give the overall approach significant clinical potential.