Passive Ankle Research Articles

Design and Evaluation of Hybrid Passive Spring Damper Ankle Foot Orthosis for Gait Performance in Drop Foot Patients: A Feasibility Study.

Passive and hybrid passive Ankle foot orthoses (AFOs) are the prevalent prescription in drop foot patients to prevent toe dragging during the swing phase. While, these AFOs have some limitations like inability to overcome foot slap, limitation in forward propulsion and inappropriate power generate at the push off. The aim of this study was to design a novel spring damper and evaluate the immediate effects of this AFO on improving the ankle kinetic and kinematic in drop foot patients. This AFO was generated from carbon composite frame and foot section with posterior hinge and spring damper actuator that controlled plantar flexion resistance at the early stance, freely dorsi flexion movement with the ability to store energy during mid-stance movement as well as restore this energy at the pre swing phase. This AFO was assessed on ten drop foot patients who used Posterior Leaf Spring AFO conditions and walked at their self-comfortable walking speed. Then the ankle kinetic and kinematic data in two conditions of with PLS (Posterior Leaf Spring) AFO, and novel spring damper AFO were assessed. Results showed a significant improve in the immediate effect of the kinetic and kinematic parameters. In conclusion, spring damper AFO improved all ankle angles in entire gait cycle as well as the ankle moments and power. Therefore, this AFO should be consider as a selective AFO in drop foot patients.

The effect of walking with elastic ankle exoskeletons on the internal force of knee and ankle

Using the passive ankle exoskeleton to reduce the energy consumption of human walking has been proposed by many researchers; however, limited knowledge of the impact of walking with the PAE on the human body has been reported. This study was to quantify the changes in the joints’ internal forces (JIFs) during assisted walking. The joint kinematic patterns must be studied as a priority, and then it was used as the input of dynamic analysis to obtain the changes of JIFs. Firstly, based on the developed human-PAE system, we simulated the PAE assisting humans walking over a series of ankle angles, and the simulation result was consistent with the experimental data that the walking angle of the ankle joint kept invariable during walking with the PAE. Furthermore, we found that the JIFs of the knee and ankle, calculated by the biomechanical modeling, decreased at different degrees. The changes in the JIFs indicated that while reducing the ankle moment of normal walking by PAE, it also brought lower JIFs. The results provided a new perspective for using the elastic elements to assist human body movement, which reduces the JIFs of humans when assisting humans walking with an elastic ankle exoskeleton.

Coronal As Well As Sagittal Fascicle Dynamics Can Bring About a Gearing Effect in Muscle Elongation by Passive Lengthening.

The amount of muscle belly elongation induced by passive lengthening is often assumed to be equal to that of fascicles. But these are different if fascicles shorter than the muscle belly rotate around their attachment sites. Such discrepancy between fascicles and muscle belly length changes can be considered as gearing. As the muscle fascicle arrangement is 3D, the fascicle rotation by passive lengthening may occur in the coronal as well as the sagittal planes. Here we examined the fascicle 3D dynamics and resultant gearing during passive elongation of human medial gastrocnemius in vivo . For 16 healthy adults, we reconstructed fascicles three-dimensionally using diffusion tensor imaging and evaluated the change in fascicle length and angles in the sagittal and coronal planes during passive ankle dorsiflexion (from 20° plantar flexion to 20° dorsiflexion). Whole muscle belly elongation during passive ankle dorsiflexion was 38% greater than the fascicle elongation. Upon passive lengthening, the fascicle angle in the sagittal plane in all regions (-5.9°) and that in the coronal plane in the middle-medial (-2.7°) and distal-medial (-4.3°) regions decreased significantly. Combining the fascicle coronal and sagittal rotation significantly increased the gearing effects in the middle-medial (+10%) and distal-medial (+23%) regions. The gearing effect by fascicle sagittal and coronal rotations corresponded to 26% of fascicle elongation, accounting for 19% of whole muscle belly elongation. Fascicle rotation in the coronal and sagittal planes is responsible for passive gearing, contributing to the whole muscle belly elongation. Passive gearing can be favorable for reducing fascicle elongation for a given muscle belly elongation.

A machine learning approach to quantify individual gait responses to ankle exoskeletons

Predicting an individual’s response to an exoskeleton and understanding what data are needed to characterize responses remains challenging. Specifically, we lack a theoretical framework capable of quantifying heterogeneous responses to exoskeleton interventions. We leverage a neural network-based discrepancy modeling framework to quantify complex changes in gait in response to passive ankle exoskeletons in nondisabled adults. Discrepancy modeling aims to resolve dynamical inconsistencies between model predictions and real-world measurements. Neural networks identified models of (i) Nominal gait, (ii) Exoskeleton (Exo) gait, and (iii) the Discrepancy (i.e., response) between them. If an Augmented (Nominal+Discrepancy) model captured exoskeleton responses, its predictions should account for comparable amounts of variance in Exo gait data as the Exo model. Discrepancy modeling successfully quantified individuals’ exoskeleton responses without requiring knowledge about physiological structure or motor control: a model of Nominal gait augmented with a Discrepancy model of response accounted for significantly more variance in Exo gait (median R2 for kinematics (0.928−0.963) and electromyography (0.665−0.788), (p<0.042)) than the Nominal model (median R2 for kinematics (0.863−0.939) and electromyography (0.516−0.664)). However, additional measurement modalities and/or improved resolution are needed to characterize Exo gait, as the discrepancy may not comprehensively capture response due to unexplained variance in Exo gait (median R2 for kinematics (0.954−0.977) and electromyography (0.724−0.815)). These techniques can be used to accelerate the discovery of individual-specific mechanisms driving exoskeleton responses, thus enabling personalized rehabilitation.

The Incidence of Gastrocnemius Tightness Among Clinic Staff in a District Hospital's Clinic in the State of Kedah, Malaysia.

Aim Musculus Gastrocnemius Tightness (MGT) has been linked with common foot and ankle pathologies. These symptoms sometimes are not severe enough for the patient to seek treatment. This study aims to determine the incidence rate of MGT among our clinical personneland if there is any association between foot and ankle symptoms with MGT. Materials and methods This observational cross-sectional study involves clinical personnel from our Specialist Clinics at Hospital Kulim, Malaysia. We interviewed and assessed 85 volunteers of which, we measured the passive ankle dorsiflexion of the volunteers (the Silfverskiöld) test, to diagnose MGT. We then used the Manchester Oxford Foot Questionnaire (MOxFQ) is used to determine the functional outcome of our volunteers. Results Out of a total of 85 volunteers assessed, 12 (14%) volunteers were found to have gastrocnemius tightness. Among this cohort, 11 were symptomatic. Out of the 73 who did not have MGT, there were three symptomatic volunteers. There was a significant association between volunteers with foot and ankle symptoms with gastrocnemius tightness, compared to those without.There was a significant difference in the relationship between the MOxFQ scores in all components (walking, pain, and social) when comparing those with and those without MGT. Conclusion We conclude that there is a significant association between foot and ankle symptoms and MGT in our clinic sample population. However, these symptoms were not severe enough for these symptomatic volunteers to seek treatment. We should consider screening symptomatic staff and implementing stretching protocols.

Biomechanical Comparison of Nonlocked Minimally Invasive and Locked Open Achilles Tendon Simulated Rupture Repairs.

Open repair of Achilles tendon ruptures is associated with a risk of infection and other wound complications. Although percutaneous repairs reduce these complications, they may increase the risk of nerve injury. This study was designed to determine whether a percutaneous nonlocking repair can approach the gapping resistance offered by a standard open repair under conditions approximating typical postoperative physiotherapy. Ten pairs of cadavers Achilles tendons were transected in situ 5 cm above the insertion. One tendon from each pair was repaired using an open 4-strand Krackow locking loop, and the contralateral tendon was repaired with the Achillon system using the same suture material. Displacement transducers were attached to the medial, lateral, anterior, and posterior aspects of the tendon, spanning the repair. Each tendon underwent 1000 tensile loading cycles to 86.5 N, simulating passive ankle range-of-motion physiotherapy. Gapping was documented on the 1st, 50th, 100th, 500th, and 1000th cycles. The ultimate tensile strength of each repaired tendon was then measured by distracting until gross failure occurred. Gapping of the percutaneous repairs exceeded that of conventional open repairs on the first, 500th, and 1000th load cycles. All 10 conventionally repaired tendons withstood 1000 load cycles without gross failure, but 4 of 10 percutaneous minimally invasive repairs failed, one on the 9th load cycle and the others between the 100th and 500th cycles. On average, tendons repaired with the open technique withstood 66% greater tensile load in failure testing than those repaired with the percutaneous technique. Open Krackow Achilles tendon repairs may better withstand more aggressive postoperative physiotherapy than nonlocked percutaneous repairs. The study suggests that surgeons should consider locking suture approaches to avoid loss of repair integrity with early motion.

Lower Limb Anthropometric Profiling in Professional Female Soccer Players: A Proof of Concept for Asymmetry Assessment Using Video Analysis.

The objective was to evaluate the clinical joint and limb measures in professional female soccer players. The study was a cross-sectional observational design. It was a preseason clinical setting. The inclusion criteria were outfield professional female soccer players, based in the UK, competing in the highest English league. The exclusion criteria included players who had had surgery in the last six months or had missed a single training session or match due to injury in the previous three months. In terms of the outcome measures, the dependent variables were the true limb length, ankle dorsiflexion, knee flexion and extension, hip flexion, extension, internal rotation and external rotation, and straight leg raise measured using video analysis software. Additionally, passive clinical knee and ankle stability tests were conducted. The independent variables were leg dominance and playing position (defender, midfielder, and attacker). For the results, all the ROM measurements demonstrated limb symmetry (p = 0.621). However, there were significant main effects of the playing position on the ankle dorsiflexion and hip internal rotation, with defenders demonstrating a significantly reduced range of motion in comparison to midfielders and attackers. A notable finding from the bilateral passive stability measures was that 38.3% of players exhibited ankle talar inversion instability when using a talar tilt. In conclusion, bilateral differences do not appear to be apparent in this population; however, positional differences may occur in the ankle and hip range of motion measures. A high proportion of this population may present with passive ankle inversion instability. Future research should consider whether this leads to a higher risk of injury in this population.

Effects of Diagnostic Tibial Nerve Block and Selective Tibial Nerve Neurotomy on Spasticity and Spastic co-contractions: A Retrospective Observational Study

Objective: To assess the effects of diagnostic nerve block and selective tibial neurotomy on spasticity and co-contractions in patients with spastic equinovarus foot.Methods: Among 317 patients who underwent a tibial neurotomy between 1997 and 2019, 46 patients who met the inclusion criteria were retrospectively screened. Clinical assessment was made before and after diagnostic nerve block and within 6 months after neurotomy. A total of 24 patients underwent a second assessment beyond 6 months after surgery. Muscle strength, spasticity, angle of catch (XV3), passive (XV1) and active (XVA) ankle range of motion were measured. The spasticity angle X (XV1–XV3) and paresis angle Z (XV1–XVA) were calculated with the knee in flexed and extended positions.Results: Tibialis anterior and triceps surae strength remained unchanged, while both Ashworth and Tardieu scores were highly reduced after nerve block and neurotomy at all measurement times. XV3 and XVA increased significantly after block and neurotomy. XV1 increased slightly after neurotomy. Consequently, spasticity angle X and paresis angle Z decreased after nerve block and neurotomy.Conclusion: Tibial nerve block and neurotomy improve active ankle dorsiflexion, probably by reducing spastic co-contractions. The results also confirmed a long-lasting decrease in spasticity after neurotomy and the predictive value of nerve blocks. LAY ABSTRACTSelective tibial nerve neurotomy is an effective surgical treatment for spastic equinovarus foot deformity after stroke. However, its effectiveness on spastic co-contractions, defined as a disabling involuntary antagonist contraction during an active agonist movement, is unknown. This retrospective study evaluated the effects of tibial neurotomy on the active ankle dorsiflexion limitation related to co- contractions. Selective tibial neurotomy allows an immediate improvement in active dorsal flexion of the ankle, probably by decreasing muscle co-contractions around this joint. This effect continues for the long term for the soleus muscle. This study also confirms that reflex spasticity is permanently reduced after neurotomy. This surgical technique therefore seems useful in limiting impairment caused by the development of spasticity and co-contractions after a stroke.

Countermovement Jump Performance Is Related to Ankle Flexibility and Knee Extensors Torque in Female Adolescent Volleyball Athletes.

Ankle flexibility and isokinetic knee torque/power generating capacity were previously suggested to contribute or to be correlated to the vertical countermovement jump (CMJ) performance. The aim of this study was to investigate the effect of the passive ankle joint dorsi flexion (θPDF) and the knee muscle's isokinetic torque and power on the CMJ in adolescent female volleyball players. The θPDF at a knee extension angle of 140 degrees were measured for 37 female post-pubertal volleyball players. Then, the players were assigned to either the flexible (n = 10) or inflexible (n = 14) groups according to earlier recommended criteria. Testing included the CMJ with and without an arm swing, and maximal knee extensions and flexions in 3 angular velocities on an isokinetic dynamometer. CMJ height performed with or without an arm swing (r(22) = 0.563, p = 0.040 and r(22) = 0.518, p = 0.009, respectively) and relative power (r(22) = 0.517, p = 0.010 and r(22) = 0.446, p = 0.030, respectively) were positively correlated with the extensors' torque at 180°/s and were negatively correlated with the flexibility level of the dominant side ankle (r(22) = -0.529, p = 0.008 and r(22) = -0.576, p = 0.030, respectively). A moderate positive correlation was also revealed between the CMJ height with and without an arm swing and the power of the non-dominant knee extensors (r(22) = 0.458, p = 0.024 and r(22) = 0.402, p = 0.049, respectively) and flexors (r(22) = 0.484, p = 0.016 and r(22) = 0.477, p = 0.018, respectively). Results of the 2 × 2 repeated ANOVA measurements revealed that flexible players jumped significantly (p < 0.05) higher during the CMJs, whilst there was a group effect only on the isokinetic knee extensor muscles' torque. In conclusion, a more flexible ankle joint and a higher isokinetic knee extensor's torque generating capacity resulted in higher CMJ performance. Therefore, ankle flexibility should be emphasized in training and is suggested to be included in preseason screening tests of youth female volleyball players.

Evaluation of Static and Dynamic Plantar Pressure Distribution along with Other Musculoskeletal Parameters in Athletes with and without Medial Tibial Stress Syndrome

ABSTRACT Background: Medial tibial stress syndrome is one of the most common overuse injuries in all running-related activities. Despite the high prevalence, various controversy exist in the literature regarding the risk factors for MTSS. Purpose: The main purpose of the present study was to evaluate and compare the risk factors for MTSS such as passive ankle range of motion, static and dynamic plantar pressure distribution, navicular drop, hip flexors, and hamstring flexibility as well as the foot posture between the athletes with MTSS and normal athletes. Materials and Methods: Fourty-eight participants after detailed assessment were recruited in the present study and were divided into two groups, Group A (subjects with MTSS) and Group B (subjects without MTSS). They all went through a musculoskeletal examination for quantifying the navicular drop, foot posture, hamstring and hip flexor’s flexibility, ankle plantarflexion and dorsiflexion range of motion. Plantar pressure analysis was used to quantify plantar pressure while standing and running. Results: Independent t-test was used. Subjects with MTSS demonstrated deficit in hamstring flexibility (P = 0.0006), dorsiflexion range of motion (P = 0.0039), a greater navicular drop (P &lt; 0.0001), and a more pronated foot posture (P = 0.0245) when compared with the normal athletes. MTSS subjects also showed more total force and pressure under the forefoot region in both static and dynamic measurement of plantar pressure. Conclusion: The findings demonstrated that MTSS is multifactorial syndrome with passive ankle range of motion, foot posture and navicular drop, plantar pressure distributions, as well as flexibility playing a major role.

Effect of passive ankle movement in the sitting position on the symptoms of chronic venous insufficiency with long-term observation.

Chronic venous insufficiency (CVI) is the most common vascular disease. One major risk factor for its development is either long-term sitting or standing in the same position and the nature of the work performed. This study aims to assess the effectiveness of passive ankle movement in the sitting position performed using the Bella Vena robot for the symptoms of CVI with long-term observation. A group of 58 patients (mean age: 59.69 ±14.59 years) with CVI in CEAP (Clinical (C), Etiological (E), Anatomical (A), and Pathophysiological (P)) classification categories 2 and 3, and a group of 37 (mean age: 51.49 ±14.86 years) healthy volunteers performing sedentary work for at least 6 h during the working day were enrolled into the study. The total duration of observation lasted 8 months (8 visits), during which the following parameters were assessed at the beginning and end of this period: pain intensity (according to the visual analogue scale (VAS)), level of saturation on the toe, pulse rate, and lower limb Doppler ultrasound evaluation of reflux parameters. The exercises used in people with CVI resulted in a significant reduction (p ≤ 0.01) in the occurrence of symptoms. Among all respondents, after 8 months of exercise, a significant reduction in pain level according to the VAS of the lower limbs, an improvement in saturation at the toe level, and a reduction in venous reflux was recorded (p ≤ 0.05). Home exercises with the use of an automatic exercise rehabilitation device alleviated significant symptoms in patients with CVI and improved the calf muscle pump.

A passive ankle dorsiflexion testing system to assess mechanobiological and structural response to cyclic loading in rat Achilles tendon

Tendinopathy is thought to be caused by repeated overload of the tendon with insufficient recovery time, leading to an inadequate healing response and incomplete recovery of preinjury material strength and function. The etiology of tendinopathy induced by mechanical load is being explored with a variety of mechanical load scenarios in small animals. This study establishes a testing system that applies passive ankle dorsiflexion to a rat hindlimb, estimates the force applied to the tendon during cyclic loading and enables the assessment of subsequent structural and biological changes. We demonstrated that the system had no drift in the applied angle, and the registered maximum angle and torque inputs and outputs were consistent between tests. We showed that cyclic loading decreased hysteresis and loading and unloading moduli with increasing cycles applied to the tendon. Histology showed gross changes to tendon structure. This work establishes a system for passively loading the rat Achilles tendon in-vivo in a physiological manner, facilitating future studies that will explore how mechanics, structure, and biology are altered by mechanical repetitive loading.

Runners with a history of shank and foot injury: Interactions among local musculoskeletal factors, age, and running experience

ObjectiveTo identify subgroups of runners’ profiles who had or did not have a History of Running-Related Injury in the Shank and Foot (HRRI-SF). DesignCross-sectional. MethodsClinical measures of passive ankle stiffness (measured as ankle position (compliance) to index passive joint stiffness), forefoot-shank alignment, peak torque of ankle plantar flexors, years of running experience, and age were analyzed through Classification and Regression Tree (CART). ResultsThe CART identified four subgroups of runners with a greater prevalence of HRRI-SF: (1) ankle stiffness ≤0.42°; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus >19,64°; (3) ankle stiffness >0.42°, age >62.5 years, and forefoot varus ≤19.70°; (4) ankle stiffness >42°, age >62.5 years, forefoot varus >19.70°, and running experience ≤7 years. Three subgroups had a lower prevalence of HRRI-SF: (1) ankle stiffness >0.42° and age between 23.5 and 62.5 years; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus ≤14.64°; (3) ankle stiffness >0.42°, age >62.5 years, forefoot varus >19.7°, and running experience >7 years. ConclusionOne runner profile subgroup showed that higher ankle stiffness could predict HRRI-SF without association with other variables. Distinct interactions among variables characterized the other subgroups' profiles. The identified interactions among the predictors used to characterize the runners’ profiles could be used in clinical decision-making.

Stability, performance and upper and lower extremities range of motion in elite beach handball athletes: A cross sectional study

Although beach handball is a popular sport worldwide, information about the functional profile in elite athletes are lacking. This study generate a descriptive profile of stability, performance and upper and lower extremities ROM in elite beach handball athletes. Secondary proposals were to compare these outcome measures between sexes and sides, and to report the frequency of athletes “at risk” according to cutoff values for shoulder ROM and dynamic postural stability of the lower extremities. Twenty-eight (n = 16 males, 28.7 ± 5.3 years; n = 12 females, 27.5 ± 5.5 years) elite beach handball athletes were tested. Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), single hop test, modified Star Excursion Balance Test (mSEBT) and passive shoulder, hip and ankle dorsiflexion ROM were assessed. Male athletes presented greater reach distance in the anterior direction [P < .0001; Mean Difference (MD): 36%] and lower reach distance in the posteromedial direction (P < .0001; MD: −29.7%) than female athletes in the mSEBT. Bilateral differences were observed for male athletes during the mSEBT, with the dominant stance limb obtaining a smaller reach distance in the anterior direction (P < .01; MD: −38.3%) and greater reach distance in the posteromedial direction (P < .0001; MD: 30.8%). Male athletes had less upper and lower extremities ROM and reached a smaller normalized single hop distance than female athletes. Most athletes presented mSEBT asymmetries and shoulder ROM deficits which have been shown to increase injury risk. Dynamic postural stability adaptations are present in elite beach handball athletes of both sexes, with more pronounced upper and lower extremity flexibility deficits in male athletes.

Design and Additive Manufacturing of a Passive Ankle-Foot Orthosis Incorporating Material Characterization for Fiber-Reinforced PETG-CF15.

The individualization of patient-specific ankle joint orthoses is becoming increasingly important and can be ideally realized by means of additive manufacturing. However, currently, there are no functional additively manufactured fiber-reinforced products that are used in the field of orthopedic treatment. In this paper, an approach as to how additively manufactured orthopedic products can be designed and produced quickly and flexibly in the future is presented. This is demonstrated using the example of a solid ankle-foot orthosis. For this purpose, test results on PETG-CF15, which were determined in a previous work, were integrated into a material map for an FEA simulation. Therewith, the question can be answered as to whether production parameters that were determined at the test specimen level can also be adapted to real, usable components. Furthermore, gait recordings were used as loading conditions to obtain exact results for the final product. In order to perfectly adapt the design of the splint to the user, a 3D scan of a foot was performed to obtain a perfect design space for topology optimization. This resulted in a patient-specific and stiffness-optimized product. Subsequently, it was demonstrated that the orthosis could be manufactured using fused layer modelling. Finally, a comparison between the conventional design and the consideration of AM-specific properties was made. On this basis, it can be stated that the wearing comfort of the patient-specific design is very good, but the tightening of the splint still needs to be improved.

Enhanced corticospinal excitability in the tibialis anterior during static stretching of the soleus in young healthy individuals.

Corticospinal excitability is known to be affected by afferent inflow arising from the proprioceptors during active or passive muscle movements. Also during static stretching (SS) afferent activity is enhanced, but its effect on corticospinal excitability received limited attention and has only been investigated as a single average value spread over the entire stretching period. Using transcranial magnetic stimulation (TMS) the present study was conducted to explore the time course of corticospinal excitability during 30 seconds SS. Motor evoked potentials (MEPs) after TMS were recorded from soleus (SOL) and tibialis anterior (TA) muscles in 14 participants during: a passive dynamic ankle dorsiflexion (DF), at six different time points during maximal individual SS (3, 6, 9, 18, 21 and 25 seconds into stretching), during a passive dynamic ankle plantar flexion (PF) and following SS. To explore the time course of corticospinal excitability during the static lengthened phase of a muscle stretch, the stretching protocol was repeated several times so that it was possible to collect a sufficient number of stimulations at each specific time point into SS, as well as during DF and PF. During passive DF, MEPs amplitude was greater than baseline in both TA and SOL (p = .001 and p = .005 respectively). During SS, MEPs amplitude was greater than baseline in TA (p = .006), but not in SOL. No differences between the investigated time points were found and no trend was detected throughout the stretching time. No effect in either muscle was observed during passive PF and after SS. These results could suggest that an increased activity of secondary afferents from SOL muscle spindles exert a corticomotor facilitation on TA. The muscle-nonspecific response observed during passive DF could instead be attributed to an increased activation within the sensorimotor cortical areas as a result of the awareness of the foot passive displacements.

Algorithm for Controlling the Movement of the Actuator of the Device for Active-Passive Mechanotherapy of the Ankle Join

Purpose of research. The article is devoted to the development of an algorithm for controlling the movement of a controlled mobile platform of a passive mechanotherapy ankle joint apparatus. One of the most common injuries sustained by humans is damage to the ankle joint in sports, domestic, industrial exercises, and as a result of car accidents. Falls from heights with a landing on the feet, including parachute jumps, also often result in ankle injuries. In order to increase the effectiveness of rehabilitation, mechanotherapy is usually used. The relevance of the topic is related to the high efficiency of robotic rehabilitation devices, which, thanks to back-linking and electrically controlled actuators, can perform lower limb movements in an optimal way.Methods. The structural diagram of the device control system has been developed. The proposed algorithm uses the strategy of paralleling control actions with the use of corrective and reference controls to calculate control voltages. Presence of force-moment feeling system enables to estimate change of reaction value in time and timely fix the moment of spastic effects appearance, muscle contracture and automatically make changes in foot movement laws in order to exclude patient's traumatisation and pain syndrome elimination.Results. A methodology for constructing the desired dependence of foot rotation angles on time in the sagittal and frontal planes is proposed. We have developed an operating algorithm for the laws of motion and decision-making block, an algorithm for generating control voltages from the reference model, an operating algorithm for the voltage correction block, and an operating algorithm for the reference model correction block. As a result of virtual tests on the mathematical model of the device, we obtained the basic patterns of motion of the actuator in the form of dependences of the rotation angle of the platform from the time.Conclusion. The results of testing the device show that controlling the movement of the actuator for active-passive mechanotherapy of the ankle joint using the algorithms described in the article is reasonable.

Continuous relative phases of walking with an articulated passive ankle–foot prosthesis in individuals with a unilateral transfemoral and transtibial amputation: an explorative case–control study

BackgroundA mechanical ankle–foot prosthesis (Talaris Demonstrator) was developed to improve prosthetic gait in people with a lower-limb amputation. This study aims to evaluate the Talaris Demonstrator (TD) during level walking by mapping coordination patterns based on the sagittal continuous relative phase (CRP).MethodsIndividuals with a unilateral transtibial amputation, transfemoral amputation and able-bodied individuals completed 6 minutes of treadmill walking in consecutive blocks of 2 minutes at self-selected (SS) speed, 75% SS speed and 125% SS speed. Lower extremity kinematics were captured and hip–knee and knee–ankle CRPs were calculated. Statistical non-parametric mapping was applied and statistical significance was set at 0.05.ResultsThe hip–knee CRP at 75% SS walking speed with the TD was larger in the amputated limb of participants with a transfemoral amputation compared to able-bodied individuals at the beginning and end of the gait cycle (p = 0.009). In people with a transtibial amputation, the knee–ankle CRP at SS and 125% SS walking speeds with the TD were smaller in the amputated limb at the beginning of the gait cycle compared to able-bodied individuals (p = 0.014 and p = 0.014, respectively). Additionally, no significant differences were found between both prostheses. However, visual interpretation indicates a potential advantage of the TD over the individual's current prosthesis.ConclusionThis study provides lower-limb coordination patterns in people with a lower-limb amputation and reveals a possible beneficial effect of the TD over the individuals’ current prosthesis. Future research should include a well-sampled investigation of the adaptation process combined with the prolonged effects of the TD.

Effectiveness of Extracorporeal Shockwave Therapy on Controlling Spasticity in Cerebral Palsy Patients: A Meta-Analysis of Timing of Outcome Measurement

Extracorporeal shockwave therapy (ESWT) has been suggested as an alternative treatment for reducing spasticity in patients with cerebral palsy (CP). However, the duration of its effect was rarely known. A meta-analysis was performed to investigate the effectiveness of ESWT at controlling spasticity in patients with CP according to the follow-up period. We included studies in which ESWT was used to manage spasticity in patients with CP, and the effect was compared with that in a control group. Finally, three studies were included. In the meta-analysis, spasticity, measured using the modified Ashworth scale (MAS), was significantly reduced after ESWT compared with that in the control group; however, it was sustained for only 1 month. After ESWT, significant increases in passive ankle range of motion (ROM) and plantar surface area in the standing position were observed compared with those in the control group and sustained for up to 3 months. Although spasticity measured using MAS was significantly reduced for only 1 month, improvement in spasticity-associated symptoms, such as ankle ROM and plantar surface area contacting the ground, persisted for over 3 months. ESWT appears to be a useful and effective therapeutic option for managing spasticity in patients with CP.

A Multidimensional Assessment of a Novel Adaptive Versus Traditional Passive Ankle Sprain Protection Systems

Background: Ankle braces aim to reduce lateral ankle sprains. Next to protection, factors influencing user compliance, such as sports performance, motion restriction, and users’ perceptions, are relevant for user compliance and thus injury prevention. Novel adaptive protection systems claim to change their mechanical behavior based on the intensity of motion (eg, the inversion velocity), unlike traditional passive concepts of ankle bracing. Purpose: To compare the performance of a novel adaptive brace with 2 passive ankle braces while considering protection, sports performance, freedom of motion, and subjective perception. Study Design: Controlled laboratory study. Methods: The authors analyzed 1 adaptive and 2 passive (one lace-up and one rigid brace) ankle braces, worn in a low-cut, indoor sports shoe, which was also the no-brace reference condition. We performed material testing using an artificial ankle joint system at high and low inversion velocities. Further, 20 male, young, healthy team sports athletes were analyzed using 3-dimensional motion analysis in sports-related movements to address protection, sports performance, and active range of motion dimensions. Participants rated subjective comfort, stability, and restriction experienced when using the products. Results: Subjective stability rating was not different between the adaptive and passive systems. The rigid brace was superior in restricting peak inversion during the biomechanical testing compared with the passive braces. However, in the material test, the adaptive brace increased its stiffness by approximately 400% during the fast compared with the slow inversion velocities, demonstrating its adaptive behavior and similar stiffness values to passive braces. We identified minor differences in sports performance tasks. The adaptive brace improved active ankle range of motion and subjective comfort and restriction ratings. Conclusion: The adaptive brace offered similar protective effects in high-velocity inversion situations to those of the passive braces while improving range of motion, comfort, and restriction rating during noninjurious motions. Clinical Relevance: Protection systems are only effective when used. Compared with traditional passive ankle brace technologies, the novel adaptive brace might increase user compliance by improving comfort and freedom of movement while offering similar protection in injurious situations.