Knee Ankle Foot Orthosis Research Articles

Effects of ankle joint degree of freedom of knee–ankle–foot orthoses on loading patterns and triceps surae muscle activity on the paretic side in individuals with subacute severe hemiplegia: a retrospective study

BackgroundIndividuals with subacute severe hemiplegia often undergo alternate gait training to overcome challenges in achieving walking independence. However, the ankle joint setting in a knee–ankle–foot orthosis (KAFO) depends on trunk function or paralysis stage for alternate gait training with a KAFO. The optimal degree of ankle joint freedom in a KAFO and the specific ankle joint conditions for effective rehabilitation remain unclear. Therefore, this study aimed to investigate the effects of different degrees of freedom of the ankle joint on center-of-pressure (CoP) parameters and muscle activity on the paretic side using a KAFO and to investigate the recommended setting of ankle joint angle in a KAFO depending on physical function.MethodsThis study included 14 participants with subacute stroke (67.4 ± 13.3 years). The CoP parameters and muscle activity of the gastrocnemius lateralis (GCL) and soleus muscles were compared using a linear mixed model (LMM) under two ankle joint conditions in the KAFO: fixed at 0° and free ankle dorsiflexion. We confirmed the relationship between changes in CoP parameters or muscle activity under different conditions and physical functional characteristics such as the Fugl–Meyer Assessment of Lower Extremity Synergy Score (FMAs) and Trunk Impairment Scale (TIS) using LMM.ResultsAnterior–posterior displacement of CoP (AP_CoP) (p = 0.011) and muscle activity of the GCL (p = 0.043) increased in the free condition of ankle dorsiflexion compared with that in the fixed condition. The FMAs (p = 0.004) and TIS (p = 0.008) demonstrated a positive relationship with AP_CoP. A positive relationship was also found between TIS and the percentage of medial forefoot loading time in the CoP (p < 0.001).ConclusionsFor individuals with severe subacute hemiplegia, the ankle dorsiflexion induction in the KAFO, which did not impede the forward tilt of the shank, promotes anterior movement in the CoP and muscle activity of the GCL. This study suggests that adjusting the dorsiflexion mobility of the ankle joint in the KAFO according to improvement in physical function promotes loading of the CoP to the medial forefoot.

A Review of Knee Ankle-Foot Orthoses in Managing Neuromuscular Disorders: Focus on Children with Cerebral Palsy

Neuromuscular disorders (NMDs) significantly impact the musculoskeletal system, leading to lower extremity muscle weakness and impaired coordination, notably affecting the quadriceps. These impairments compromise knee stability during standing and walking, increasing fall risks and hindering mobility and independence. Knee-ankle-foot orthoses (KAFOs) are vital in enhancing gait efficiency and knee stability. Traditional locked KAFOs rigidly immobilize the knee throughout the gait cycle, offering maximal stability but limited natural movement. Advances in orthotic technology have led to the development of stance control KAFOs (SCKAFOs), which dynamically lock the knee only during the stance phase, promoting a more natural and energy-efficient gait. The E-MAG Active and NEURO TRONIC knee joints are prominent examples of SCKAFOs, featuring sophisticated electronic control mechanisms to improve functional outcomes in individuals with NMDs. This review also focuses on the application of SCKAFOs in children with cerebral palsy (CP), the most common neuromotor disorder affecting movement, posture, and muscle tone due to early brain injury. The prevalence and diverse etiologies of CP necessitate individualized therapeutic interventions. The review aims to evaluate the efficacy and satisfaction of orthotic management in pediatric CP, providing evidence-based recommendations for optimizing orthotic interventions and enhancing quality of life for affected children and their families.

Quadriceps muscle activity during walking with a knee ankle foot orthosis is associated with improved gait ability in acute hemiplegic stroke patients with severe gait disturbance.

A knee-ankle-foot orthosis (KAFO) prevents knee buckling during walking and enables gait training for acute hemiplegic stroke patients with severe gait disturbances. Although the goal of gait training with a KAFO is to improve gait ability, that is, to acquire walking with an ankle-foot orthosis (AFO), it is not clear how gait training with a KAFO contributes to improving gait ability. Therefore, this study aimed to investigate the relationship between muscle activities during walking with a KAFO and the improvement of gait ability in hemiplegic stroke patients with severe gait disturbance. A prospective cohort study was conducted. Fifty acute hemiplegic stroke patients who could not walk with an AFO participated. Muscle activities of the paretic rectus femoris, biceps femoris, tibialis anterior, and soleus were assessed with surface electromyogram during walking with a KAFO. Electromyograms were assessed at the beginning of gait training and at the time the Ambulation Independence Measure score improved by 3 or higher, or discharge. Even in patients with complete hemiplegia, paretic rectus femoris, biceps femoris, and soleus showed periodic muscle activity during walking with a KAFO. Twenty-three patients improved to an Ambulation Independence Measure score of 3 or higher and were able to walk with an AFO (good recovery group). At the beginning of gait training, paretic rectus femoris muscle activity during the first double-limb support phase was significantly higher in the good recovery group than in the poor recovery group. The rectus femoris muscle activity significantly increased from before to after acute rehabilitation, which consisted mainly of gait training with a KAFO. For acute hemiplegic stroke patients with severe disturbance, the induction and enhancement of paretic quadriceps muscle activity during walking with a KAFO play an important role in acquiring walking with an AFO.

Efficacy of Lower Limb Orthoses in the Rehabilitation of Children Affected by Cerebral Palsy: A Systematic Review.

Lower limb orthoses are frequently used in children suffering from cerebral palsy (CP) alongside rehabilitation. The aim of this study was to analyze the effectiveness of ankle-foot orthosis (AFO) and knee-ankle-foot orthosis (KAFO) in walking, balance maintenance, spasticity, and quality of life improvement during rehabilitation in children affected by CP. The hypothesis was that the use of orthoses could improve the parameters compared to non-use. A systematic review was conducted in the main databases, including English language RCTs published about the use of AFO and KAFO in combination or not with rehabilitation methods in children affected by CP and studies mentioning walking, balance, muscle length, and quality of life as outcomes. From an initial number of 1484 results, a final number of 11 RCTs were included, comprising a total number of 442 participants and showing an overall high risk of bias in 10 studies and some concerns in one study. Six studies investigated the domain of walking, four studies investigated the domain of balance, and two studies investigated how KAFO and AFO orthoses could improve and prevent muscle contractures. Using highly heterogeneous study designs, different kinds of orthoses and different assessment tools were used. Further studies conducted with higher methodological quality are needed to establish whether AFO and KAFO are useful or not in combination with rehabilitation in improving the investigated domains.

Determination of Gait Events and Temporal Gait Parameters for Persons with a Knee-Ankle-Foot Orthosis.

Gait event detection is essential for controlling an orthosis and assessing the patient's gait. In this study, patients wearing an electromechanical (EM) knee-ankle-foot orthosis (KAFO) with a single IMU embedded in the thigh were subjected to gait event detection. The algorithm detected four essential gait events (initial contact (IC), toe off (TO), opposite initial contact (OIC), and opposite toe off (OTO)) and determined important temporal gait parameters such as stance/swing time, symmetry, and single/double limb support. These gait events were evaluated through gait experiments using four force plates on healthy adults and a hemiplegic patient who wore a one-way clutch KAFO and a pneumatic cylinder KAFO. Results showed that the smallest error in gait event detection was found at IC, and the largest error rate was observed at opposite toe off (OTO) with an error rate of -2.8 ± 1.5% in the patient group. Errors in OTO detection resulted in the largest error in determining the single limb support of the patient with an error of 5.0 ± 1.5%. The present study would be beneficial for the real-time continuous monitoring of gait events and temporal gait parameters for persons with an EM KAFO.

Lower limb muscle strength of the affected side in stroke patients is an accurate predictor of the need for a KAFO.

Accurate prediction of recovery is essential to determine whether a knee-ankle-foot orthosis (KAFO) is required in the subacute phase of stroke. However, there are currently no reliable methods to predict such recovery. This study aimed to determine whether muscle strength of the affected lower limb (affected side LL strength) in stroke patients in the subacute phase who cannot walk without a KAFO can be used to predict the continuous need for a KAFO, using a hand-held dynamometer. We enrolled patients with severe hemiplegia (n = 51) who were unable to walk without a KAFO for 10 days after stroke onset. They were divided into two groups depending on the continuous need for a KAFO at 1 month after onset; the KAFO and non-KAFO groups. Logistic regression analysis was used to investigate whether the affected side LL strength was a predictor of the continuous need for a KAFO at 1 month after onset. In addition, significant predictors were analyzed using receiver operating characteristic (ROC) curves. The KAFO and non-KAFO groups included 23 (45.10%) and 28 (54.90%) patients, respectively. The affected side LL strength and pusher syndrome severity were identified as predictors of the continuous need for a KAFO. The predictor with the highest predictive ability was the affected side LL strength, with an area under the ROC curve of 0.80 (95% CI, 0.68-0.93). Affected side LL strength may be a highly accurate predictor of the need for a KAFO in the subacute phase of stroke.

Predictors indicating the continuous need for a knee-ankle-foot orthosis in stroke patients at 1 month after onset

ObjectivesTo investigate predictors indicating the continuous need for a knee-ankle-foot orthosis (KAFO) at 1 month after stroke onset in patients who cannot walk without a KAFO in the acute period. Materials and methodsWe enrolled patients with severe hemiplegia (n = 139) who were unable to walk without a KAFO on day 10 from stroke onset. The patients were divided into two groups depending on the need for a KAFO at 1 month after the onset: the KAFO group and non-KAFO group. Logistic regression analysis was used to identify predictors of the continuous need for a KAFO at 1 month after stroke onset. In addition, significant predictors were analyzed using receiver operating characteristic curves. ResultsThe number of patients in the KAFO group and non-KAFO group was 72 (51.8 %) and 67 (48.2 %), respectively. Motor deficit, sensation disorder, severity of pusher syndrome, and body mass index were identified as predictors of the continuous need for a KAFO. Moreover, active range of motion of knee extension on the affected side was found to have the highest predictive ability, with an area under the receiver operating characteristic curve of 0.89 (95 % confidence interval, 0.83–0.94). ConclusionsIn this study, multiple factors were associated with the continuous need for a KAFO at 1 month after stroke onset. In particular, active range of motion of knee extension on the affected side is suggested to be a highly accurate predictor for the need for a KAFO in the subacute phase.

Lightweight design of Knee-Ankle-Foot Orthotic Devices using Voronoi patterns for Additive Manufacturing

Traditionally fabricated knee-ankle-foot orthosis (KAFO) device that is used to aid in the mobility user is uncomfortable. Problems such as weight and enclosure in almost all the part of the leg make it strenuous and humid for the user to wear for a long time. Furthermore, in the traditional production method, it can take up to a week to fabricate. The aim of this study is to redesign the knee-ankle-foot-orthosis by using the application of topology optimization in order to reduce the material used on the product and to make it lightweight. The parameters of the KAFO were determined by using indirect method; similar to traditional method. The modelling and analysis of the KAFO is completed by using CAD and CAE software. Optimization of the product is performed by redesigning the shape and applying topology optimization function. It is able to reduce the maximum stress of the product by 22.56% and the volume by 4.33%. Application of the Voronoi pattern further reduces the mass of the KAFO and produces more organic looks to the product. SLS Lisa Pro 3D printer is used to produce the KAFO in a period of less than a week. This prove to be a viable alternative for producing customized KAFO.

A microprocessor stance and swing control orthosis improves balance, risk of falling, mobility, function, and quality of life of individuals dependent on a knee-ankle-foot orthosis for ambulation

Introduction The C-Brace microprocessor stance and swing control orthosis was designed to overcome safety and functional limitations of traditional knee-ankle-foot orthoses (KAFOs) for individuals with lower limb paresis. However, a systematic comparison to established KAFO types has not been performed in a bigger sample. Methods International multicenter, randomized, controlled, cross-over clinical trial. Legacy KAFO users at risk of falling were randomized to KAFO/C-Brace or C-Brace/KAFO use for three months with each orthosis. Primary outcome was balance assessed with the Berg Balance Scale (BBS). Secondary outcomes were falls, mobility, function, and quality of life. Results Intention-to-treat analysis with 102 participants. With the C-Brace, the BBS improved by 3.3 ± 6.3 points (p < 0.0001). Significantly fewer participants presented BBS scores <40 indicative of increased fall risk (16 vs. 36, p = 0.018). Mean falls reduced from 4.0 ± 16.8 to 1.1 ± 3.3 (p = 0.002). Outcomes for function, mobility, and quality of life showed significant improvements with the C-Brace. Discussion The improvements in fall risk and mobility can be attributed to the stumble recovery and controlled knee flexion during weight bearing of the C-Brace and have a positive impact on the quality of life of users. Conclusion The C-Brace represents an option for KAFO users with increased fall risk and reduced mobility.

Long-term locked knee ankle foot orthosis use: A perspective overview of iatrogenic biomechanical and physiological perils.

A knee ankle foot orthosis (KAFO) may be prescribed to the person with severe neuromusculoskeletal impairment of the lower limb to promote walking stability. The locked knee ankle foot orthosis (L-KAFO) is among the KAFO's routinely prescribed; however, long-term use of the L-KAFO is associated with musculoskeletal (arthrogenic and myogenic) and integumentary changes, and gait asymmetry with increased energy expenditure. Consequently, the risk of developing low back pain, osteoarthritis of the lower limbs and spinal joints, skin dermatitis, and ulceration increases, all of which impact quality of life. This article synthesizes the iatrogenic biomechanical and physiological perils of long-term L-KAFO use. It promotes using recent advances in rehabilitation engineering to improve daily activities and independence for proper patient groups.

Do Knee Joint Orthoses Affect the Functional Status of Stroke Patients? A Literature Review

Stroke is the leading cause of adult disability in developed countries. As a result of damage to the central nervous system, the patient's independence in performing everyday activities is reduced, which often leads to dependence on the environment. The symptoms of syndromes affect many functions, including: speech, the upper limb, gait, balance and coordination disorders. These disorders lead to a decrease in the patient's quality of life. Many patients require knee braces to learn to walk. In this review article, the most commonly used scales used to assess the functional status of patients after stroke are discussed, with particular attention being paid to gait assessment. We described simple (basic ADL) and instrumental (extended) scales of activities of daily living (instrumental, extended ADL), methods of clinical gait and balance assessment, International Classification of Functioning, Disability and Health, ICF), as well as recommendations of the European Stroke Organisation (ESO, Neurorehabilitation Committee). These guidelines regard methods of evaluating the results of post-stroke rehabilitation for clinical use - Outcome Measures for Clinical Use, in which, among others, the Berg scale and the timed Up &amp; Go test are recommended for the lower limb, the Barthel scale and the Functional Independence Measure for ADL, and the Stroke Impact Scale for the participation column in all 3 ICF domains. In the article, the current state of knowledge is presented regarding the impact of knee braces on the functional status of people after stroke. Mechanical knee and ankle orthoses are called KAFO (Knee Ankle Foot Orthosis). Their main tasks include immobilisation of the knee joint and aid in learning to walk.

Effects of orthoses on muscle activity and synergy during gait.

An orthosis is often used in rehabilitation to improve kinetic and kinematic parameters during gait. However, whether changes in neural control depend on wearing an orthosis during gait is unclear. We measured the muscle activity and synergy of the lower limb muscles without orthosis and with two types of orthoses: ankle-foot orthosis (AFO) and knee-ankle-foot orthosis (KAFO). Muscle activity during gait was measured in 15 healthy adults, and muscle synergies were extracted using non-negative matrix factorization. The results revealed that some muscle activities were significantly different among the three conditions. Post-hoc analysis indicated differences between each condition. Knee extensor muscle activity related to the loading response was significantly increased by wearing the AFO. In the KAFO condition, hip abductor muscle activity related to weight bearing was significantly decreased, and ankle dorsiflexor muscle activity was increased to secure clearance during the swing phase. However, the number of muscle synergies and complexity of muscle synergy did not significantly change among these conditions. However, along with changes in muscle activity, the activation pattern and weightings of muscle synergies tended to change with the use of orthoses. Each muscle activity was changed by wearing the orthosis; however, the immediate mechanical constraint did not change the framework of muscle synergy.

Effects of specialist care lower limb orthoses on personal goal attainment and walking ability in adults with neuromuscular disorders.

Lower limb orthoses intend to improve walking in adults with neuromuscular disorders (NMD). Yet, reported group effects of lower limb orthoses on treatment outcomes have generally been small and heterogeneous. We propose that guideline-based orthotic care within a multidisciplinary expert setting may improve treatment outcomes. To examine the effectiveness of specialist care orthoses compared to usual care orthoses on personal goal attainment and walking ability. Cohort study. Adults with NMD who experienced walking problems due to calf and/or quadriceps muscle weakness and were provided with a specialist care lower limb orthosis between October 2011 and January 2021. Three months after provision, the specialist care orthosis was compared to the usual care orthosis worn at baseline in terms of personal goal attainment (Goal Attainment Scaling (GAS)), comfortable walking speed (m/s), net energy cost (J/kg/m) (both assessed during a 6-minute walk test), perceived walking ability and satisfaction. Sixty-four adults with NMD were eligible for analysis. The specialist care orthoses comprised 19 dorsiflexion-restricting ankle-foot orthoses (AFOs), 22 stance-control knee-ankle-foot orthoses (KAFOs) and 23 locked KAFOs. Overall, 61% of subjects showed a clinically relevant improvement in GAS score. Perceived safety, stability, intensity, fear of falling and satisfaction while walking all improved (p≤0.002), and subjects were satisfied with their specialist care orthosis and the services provided. Although no effects on walking speed or net energy cost were found in combined orthosis groups, specialist care AFOs significantly reduced net energy cost (by 9.5%) compared to usual care orthoses (from mean (SD) 3.81 (0.97) to 3.45 (0.80) J/kg/m, p = 0.004). Guideline-based orthotic care within a multidisciplinary expertise setting could improve treatment outcomes in adults with NMD compared to usual orthotic care by improvements in goal attainment and walking ability. A randomized controlled trial is now warranted to confirm these results.

Robotized Knee-Ankle-Foot Orthosis-Assisted Gait Training on Genu Recurvatum during Gait in Patients with Chronic Stroke: A Feasibility Study and Case Report.

Genu recurvatum (knee hyperextension) is a common problem after stroke. It is important to promote the coordination between knee and ankle movements during gait; however, no study has investigated how multi-joint assistance affects genu recurvatum. We are developing a gait training technique that uses robotized knee-ankle-foot orthosis (KAFO) to assists the knee and ankle joints simultaneously. This report aimed to investigate the safety of robotized KAFO-assisted gait training (Experiment 1) and a clinical trial to treat genu recurvatum in a patient with stroke (Experiment 2). Six healthy participants and eight patients with chronic stroke participated in Experiment 1. They received robotized KAFO-assisted gait training for one or 10 sessions. One patient with chronic stroke participated in Experiment 2 to investigate the effect of robotized KAFO-assisted gait training on genu recurvatum. The patient received the training for 30 min/day for nine days. The robot consisted of KAFO and an attached actuator of four pneumatic artificial muscles. The assistance parameters were adjusted by therapists to prevent genu recurvatum during gait. In Experiment 2, we evaluated the knee joint angle during overground gait, Fugl-Meyer Assessment of lower extremity (FMA-LE), modified Ashworth scale (MAS), Gait Assessment and Intervention Tool (G.A.I.T.), 10-m gait speed test, and 6-min walk test (6MWT) before and after the intervention without the robot. All participants completed the training in both experiments safely. In Experiment 2, genu recurvatum, FMA-LE, MAS, G.A.I.T., and 6MWT improved after robotized KAFO-assisted gait training. The results indicated that the multi-joint assistance robot may be effective for genu recurvatum after stroke.

Long-term Observation in Patients with Duchenne Muscular Dystrophy with Early Introduction of a Standing Program Using Knee-ankle-foot Orthoses.

This study investigated the outcomes of the early introduction of a standing program for patients with Duchenne muscular dystrophy (DMD). This was a retrospective observational study of 41 outpatients with DMD aged 15-20 years. We introduced the standing program using knee-ankle-foot orthoses (KAFO) to slow the progression of scoliosis when ankle dorsiflexion became less than 0° in the ambulatory period. Thirty-two patients with DMD were offered the standing program with KAFO; 12 continued the program until the age of 15 years (complete group) and 20 discontinued the program before the age of 15 years (incomplete group). The non-standing program group included 9 patients. The standing program with KAFO was significantly associated with the Cobb angle at the age of 15 years after adjustment for the duration of corticosteroid use and DMD mutation type (P=0.0004). At the age of 15 years, significant correlations were found between the ankle dorsiflexion range of motion (ROM) and non-ambulatory period (P=0.0010), non-ambulatory period and Cobb angle (P<0.0001), Cobb angle and percent predicted forced vital capacity (P=0.0004), and ankle dorsiflexion ROM and Cobb angle (P=0.0066). In the complete group, the age at ambulation loss (log-rank P=0.0015), scoliosis progression (log-rank P=0.0032), and pulmonary dysfunction (log-rank P=0.0006) were significantly higher than in the non-standing program group. The early introduction of a standing program for DMD patients may prolong the ambulation period and slow the progression of scoliosis and pulmonary dysfunction.

Comparison of anterior and posterior wheeled walkers based on body weight support in improving gait function a subjects with spinal cord injury: A case study.

The majority of people with muscle weakness or paralysis lose their ability to walk and require various assistive devices like a walker to walk. Although various studies have examined the effect of different types of anterior and posterior walkers on different walking variables, so far no studies compare anterior versus posterior walker on forces and torques applied to the lower extremities. This paper presents a novel approach of using a passive saddle-assistive device (S-AD) to investigate the effect of this device on the torques of the joints. To measure the effectiveness of the device, a volunteer with spinal cord injury (SCI) participated to walk in four modes; including the use of a standard walker, anterior, and posterior mobility S-AD with and without body weight support, in the gait laboratory. The forces and torques applied to the lower and upper limbs were measured and examined. The result demonstrated a reduction in the vertical force on the lower limb in the anterior S-AD in supporting the patient's weight compared to the standard walker up to 42.8% and to the posterior S-AD with weight support up to 12%. According to the results, the anterior S-AD has a greater effect compared to posterior S-AD and standard walkers on lower and upper limb torque and forces during walking of a SCI patient while using knee ankle-foot orthoses.

Comparing walking with knee-ankle-foot orthoses and a knee-powered exoskeleton after spinal cord injury: a randomized, crossover clinical trial

Recovering the ability to stand and walk independently can have numerous health benefits for people with spinal cord injury (SCI). Wearable exoskeletons are being considered as a promising alternative to conventional knee-ankle-foot orthoses (KAFOs) for gait training and assisting functional mobility. However, comparisons between these two types of devices in terms of gait biomechanics and energetics have been limited. Through a randomized, crossover clinical trial, this study compared the use of a knee-powered lower limb exoskeleton (the ABLE Exoskeleton) against passive orthoses, which are the current standard of care for verticalization and gait ambulation outside the clinical setting in people with SCI. Ten patients with SCI completed a 10-session gait training program with each device followed by user satisfaction questionnaires. Walking with the ABLE Exoskeleton improved gait kinematics compared to the KAFOs, providing a more physiological gait pattern with less compensatory movements (38% reduction of circumduction, 25% increase of step length, 29% improvement in weight shifting). However, participants did not exhibit significantly better results in walking performance for the standard clinical tests (Timed Up and Go, 10-m Walk Test, and 6-min Walk Test), nor significant reductions in energy consumption. These results suggest that providing powered assistance only on the knee joints is not enough to significantly reduce the energy consumption required by people with SCI to walk compared to passive orthoses. Active assistance on the hip or ankle joints seems necessary to achieve this outcome.

Experts' Perceived Patient Burden and Outcomes of Knee-ankle-foot-orthoses (Kafos) Vs. Microprocessor-stance-and-swing-phase-controlled-knee-ankle-foot Orthoses (Mp-sscos).

Patients with neuromuscular knee-instability assisted with orthotic devices experience problems including pain, falls, mobility issues and limited engagement in daily activities. The aim of this study was to analyse current real-life burden, needs and orthotic device outcomes in patients in need for advanced orthotic knee-ankle-foot-orthoses (KAFOs). An observer-based semi-structured telephone interview with orthotic care experts in Germany was applied. Interviews were transcribed and content-analysed. Quantitative questions were analysed descriptively. Clinical experts from eight centres which delivered an average of 49.9 KAFOs per year and 13.3 microprocessor-stance-and-swing-phase-controlled-knee-ankle-foot orthoses (MP-SSCOs) since product availability participated. Reported underlying conditions comprised incomplete paraplegia (18%), peripheral nerve lesions (20%), poliomyelitis (41%), post-traumatic lesions (8%) and other disorders (13%). The leading observed patient burdens were "restriction of mobility" (n=6), followed by "emotional strain" (n=5) and "impaired gait pattern" (n=4). Corresponding results for potential patient benefits were seen in "improved quality-of-life" (n=8) as well as "improved gait pattern" (n=8) followed by "high reliability of the orthosis" (n=7). In total, experts reported falls occurring in 71.5% of patients at a combined annual frequency of 7.0 fall events per year when using KAFOs or stance control orthoses (SCOs). In contrast, falls were observed in only 7.2 % of MPSSCO users. Advanced orthotic technology might contribute to better quality of life of patients, improved gait pattern and perceived reliability of orthosis. In terms of safety a substantial decrease in frequency of falls was observed when comparing KAFO and MP-SSCO users.

Evaluation of Optimal Control Approaches for Predicting Active Knee-Ankle-Foot-Orthosis Motion for Individuals With Spinal Cord Injury.

Gait restoration of individuals with spinal cord injury can be partially achieved using active orthoses or exoskeletons. To improve the walking ability of each patient as much as possible, it is important to personalize the parameters that define the device actuation. This study investigates whether using an optimal control-based predictive simulation approach to personalize pre-defined knee trajectory parameters for an active knee-ankle-foot orthosis (KAFO) used by spinal cord injured (SCI) subjects could potentially be an alternative to the current trial-and-error approach. We aimed to find the knee angle trajectory that produced an improved orthosis-assisted gait pattern compared to the one with passive support (locked knee). We collected experimental data from a healthy subject assisted by crutches and KAFOs (with locked knee and with knee flexion assistance) and from an SCI subject assisted by crutches and KAFOs (with locked knee). First, we compared different cost functions and chose the one that produced results closest to experimental locked knee walking for the healthy subject (angular coordinates mean RMSE was 5.74°). For this subject, we predicted crutch-orthosis-assisted walking imposing a pre-defined knee angle trajectory for different maximum knee flexion parameter values, and results were evaluated against experimental data using that same pre-defined knee flexion trajectories in the real device. Finally, using the selected cost function, gait cycles for different knee flexion assistance were predicted for an SCI subject. We evaluated changes in four clinically relevant parameters: foot clearance, stride length, cadence, and hip flexion ROM. Simulations for different values of maximum knee flexion showed variations of these parameters that were consistent with experimental data for the healthy subject (e.g., foot clearance increased/decreased similarly in experimental and predicted motions) and were reasonable for the SCI subject (e.g., maximum parameter values were found for moderate knee flexion). Although more research is needed before this method can be applied to choose optimal active orthosis controller parameters for specific subjects, these findings suggest that optimal control prediction of crutch-orthosis-assisted walking using biomechanical models might be used in place of the trial-and-error method to select the best maximum knee flexion angle during gait for a specific SCI subject.

Impact of Alternate Gait Training Using Knee-Ankle-Foot Orthoses with Oil Damper Ankle Hinge in Patients with Subacute Severe Hemiplegia.

Patients with severe hemiplegia along with knee instability require knee–ankle–foot orthoses (KAFOs) for gait training. However, in these patients, it is unclear which type of walking training is more effective to improve gait function. Providing alternate gait training (AGT) improves walking function in patients with spinal cord injury, but it is still unclear whether this is effective in hemiplegic stroke patients. In this study, we defined “unified AGT” as AGT performed with the same therapeutic concept by physiotherapists. We then investigated whether AGT improved gait function quicker than our traditional gait training in hemiplegic stroke patients. We enrolled 15 subjects with severe hemiplegia and knee instability who had undergone unified AGT using KAFOs with hinged oil dampers at the ankles, and 30 historical control (HC) subjects who had undergone traditional gait training. We used multiple comparison and survival analyses to analyze the differences in the functional independence measure (FIM) gait score changes between the two groups. The multiple comparison revealed a significant increase (p < 0.05) in the FIM gait score compared with its initial score in the subjects with unified AGT. However, this improvement was not seen in the HC subjects. Additionally, the survival analysis of time taken to recover revealed a significant difference between the subjects with unified AGT and HC subjects (p < 0.05). These findings suggest that unified AGT using a KAFO facilitates gait improvement in patients with severe hemiplegia and knee instability.