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Diagnosing foot complaints using plantar pressure videos is complicated by the presence of confounding factors (e.g. age, weight). Outlier detection could help with diagnosis, but these confounding factors result in data that is not independent and identically distributed (IID) with respect to a specific patient. To address this non-IID problem, we propose the modeling of confounding factors using metric learning. A distance metric is learned on the confounding factors in order to model their impact on the plantar pressures. This metric is then employed to weight plantar pressures from healthy controls when generating a patient-specific statistical baseline. Statistical parametric mapping is then used to compare the patient to this statistical baseline. We show that using metric learning reduces variance in these statistical baselines, which then improves the sensitivity of the outlier detection. These improvements in outlier detection get us one step closer to accurate computer-aided diagnosis of foot complaints.

Contains fulltext : 238575.pdf (Publisher’s version ) (Closed access) This study aims were twofold: (1) to evaluate the construct validity of the Repetitive Movement Test (RMT) a novel test developed for Wheelchair Rugby classification which evaluates arm coordination impairment at five joints - shoulder, elbow, forearm, wrist and fingers - and (2), pending sufficiently positive results, propose objective minimum impairment criteria (MIC). Forty-two WR athletes with an eligible coordination impairment, and 20 volunteers without impairment completed the RMT and two clinically established coordination tests: the finger-nose test (FNT) and the spiral test (ST). Coordination deduction (CD), an ordinal observational coordination scale, currently used in WR classification, was obtained. Spearman-rank correlation coefficients (SCC) between RMT and ST (0.40 to 0.67) and between RMT and CD (0.31 to 0.53) generally supported RMT construct validity, SCC between RMT and FNT were lower (0.12-0.31). When the scores on ST, FNT and RMT from the sample of WR players were compared with the scores from volunteers without impairment, 93.5% to 100% of WR players had scores > 2SD below the mean of volunteers without impairment on the same test. In conclusion, RMT at the elbow, forearm, wrist and fingers have sufficient construct validity for use in WR. MIC were recommended with ST and RMT.

To examine changes in quality of life (QoL) after an eight-week period of robotic exoskeleton training in a homogeneous group of patients with chronic complete spinal cord injury (SCI).Prospective single-group pre-post study.Rehabilitation center.Patients with a chronic (6 months) motor complete SCI (T1-L1).Twenty-four training sessions with the ReWalk exoskeleton over an eight-week period.QoL, assessed with the sum score of the Short Form-36 with Walk Wheel modification (SF-36ww). Secondary outcome measures were the eight SF-36ww subdomains, satisfaction with bladder and bowel management, lower extremity joint passive range of motion (pROM), and lower extremity spasticity.Twenty-one participants completed the training. QoL significantly improved after the training period (average SF-36 sum score 621 ± 90) compared to baseline (571 ± 133) (Even in patients with chronic motor complete SCI and a relatively high level of QoL at baseline, a short-term exoskeleton training improved their QoL, pain and satisfaction with bladder management; findings that warrant further controlled studies in this specific SCI population.

Background Improvement of balance control is an important rehabilitation goal for patients with motor and sensory impairments. To quantify balance control during walking, various stability outcome measures have described differences between healthy controls and patient groups with balance problems. To be useful for the evaluation of interventions or monitoring of individual patients, stability outcome measures need to be reliable. Research question What is the test-retest reliability of six stability outcome measures during gait? Methods Patients with balance problems (n = 45) and healthy controls (n = 20) performed two times a two-minute walk test (2MWT). The intraclass correlation coefficient (ICC) and Bland-Altman analysis (coefficient of repeatability; CR) were used to evaluate the test-retest reliability of six stability outcome measures: dynamic stability margin (DSM), margin of stability (MoS), distance between the extrapolated centre of mass (XCoM) and centre of pressure (CoP) in anterior-posterior (XCoM-CoPAP) and medial-lateral (XCoM-CoPML) direction, and inclination angle between centre of mass (CoM) and CoP in anterior-posterior (CoM-CoPAP-angle) and medial-lateral (CoM-CoPML-angle) direction. A two way mixed ANOVA was performed to reveal measurement- and group-effects. Results The ICCs of all stability outcome measures ranged between 0.51 and 0.97. Significant differences between the measurements were found for the DSM (p = 0.017), XCoM-CoPAP (p = 0.008) and CoM-CoPAP-angle (p = 0.001). Significant differences between controls and patients were found for all stability outcome measures (p Significance Based on the ICCs, the reliability of all stability outcome measures was moderate to excellent. Since the XCoM-CoPML and CoM-CoPML-angle showed no differences between the measurements and smaller CRs than the differences between patients and controls, the XCoM-CoPML and CoM-CoPML-angle seem the most promising stability outcome measures to evaluate interventions and monitor individual patients.

Background: Although posterior spinal correction and fusion surgery (PSF) of adolescent idiopathic scoliosis (AIS) limits counter rotation between thorax and pelvis, the physical function, and more specifically gait of these patients is only slightly affected after PSF. Possibly, shoulders-thorax counter-rotation increases to compensate for the loss in thorax-pelvis motion. This would subsequently result in a higher phase-difference and range of motion (ROM) between the shoulders and thorax. Research questions: What is the effect of PSF on the phase difference and ROM between the shoulders and thorax? What is the effect of PSF on upper body deformity? Methods: 18 AIS patients underwent gait analysis at increasing walking speeds (0.45 to 2.22 m/s) before, and 3 and 12 months after PSF. The phase difference, ROM, and deformity between the shoulders, thorax, and pelvis were calculated. Results: The shoulders- thorax phase difference was unaffected by surgery. At 3 months postoperatively the shoulders-thorax ROM was decreased (3.5° ± 0.2° versus 2.7° ± 0.2° p=0.001). This recovered to preoperative values 12 months postoperatively (3.2° ± 0.2° p=0.213). The shoulder-pelvis phase difference was decreased 3 months postoperatively (−98.9° ± 6.8° vs. −77.2° ± 7.2° p=0.010), and recovered to pre-op values at the 12 months postoperative measurement (−89.6° ± 6.9° p=0.290). Walking speed did not influence the effect of surgery on phase difference or ROM. The pre-operative shoulders-thorax asymmetry decreased from 3.4° ± 2.4° to 0.6° ± 3.1° (p

Contains fulltext : 238558.pdf (Publisher’s version ) (Open Access) PURPOSE OF THE ARTICLE: Learning to use an exoskeleton is time consuming and diverse between users. Knowledge about trainability of exoskeleton skills is relevant for planning and expectation management. The objective was to assess predictors of exoskeleton skill performance during and after exoskeleton training. MATERIALS AND METHODS: Twenty-four participants with a motor complete spinal cord injury were given 24 training sessions in 8 weeks. Nine potential predictors were identified: lesion level, age, gender, age at injury, time since injury, BMI, sport, active lifestyle, and anxiety. Univariate and multivariate linear regression analyses were performed to examine predictors of skill performance after 2, 4, 6, and 8 weeks. RESULTS AND CONCLUSIONS: Twenty participants completed the training. Univariate analysis revealed that positive predictors were: low lesion level and more active lifestyle after 2 weeks, whereas low age at injury, low BMI, and more active lifestyle were positive predictors after 6 weeks. Multivariate regression model explained 65% of the performance after 2 weeks (predictors: lesion level, anxiety, active lifestyle) and 66% after 6 weeks (predictors: BMI, active lifestyle, age). Lesion level was a predictor during the first 4 weeks, but did not influence participants' final skill level. BMI, age, and active lifestyle were predictors toward the end of the training period.Implications for rehabilitationWith the help of wearable exoskeletons people with a complete spinal cord injury can regain their standing and walking mobility.Learning to use an exoskeleton is time consuming and the number of training sessions required to walk independently differs greatly between users.This study shows that lesion level was an important predictor of exoskeleton motor learning in the first 4 weeks of training.BMI, age, and active lifestyle were predictors of exoskeleton skill performance toward the end of the 8 week training period.

Gait impairments in people with Charcot Marie Tooths disease are the combined result of ankle-foot deformities, muscle weakness, and somatosensory impairments. People with Charcot-Marie-Tooth disease often experience pain and difficulties when walking, especially barefoot. They also trip and fall frequently and have a lower than normal gait speed and distance. Because these gait impairments and related complaints are disabling, clinical management aimed at improving gait is important. Management involves both conservative and surgical treatment options, each with limited scientific evidence. However, a treatment algorithm that describes both conservative and surgical treatment options is currently lacking. This study sets out a step-wise treatment algorithm, based on evidence, if available, and otherwise reflecting practice-based experience. The treatment algorithm will be of value in daily clinical practice, and will serve as a template for future research.

Background: In infants with indications of upper cervical dysfunction, the Flexion-Rotation-Test and Lateral-Flexion-Test are used to indicate reduced upper cervical range-of-motion (ROM). In infants, the inter-rater reliability of these tests is unknown. Objective: To assess the inter-rater reliability of subjectively and objectively measured ROM by using the Flexion-Rotation-Test and Lateral-Flexion-Test. Methods: 36 infants (

Background: Exoskeleton use by people with complete spinal cord injury (SCI) in daily life is still a challenge. To optimize its daily life use, a better understanding of the purpose of use and the accompanying improvements are needed. The perspective of experienced exoskeleton users provides an important contribution to the improvement of future exoskeletons.Methods: Face-to-face semi-structured interviews were held with 13 people with SCI, who were experienced exoskeleton users. Interviews were audio-taped, transcribed and analysed thematically.Results: Participants expressed three future purposes of exoskeleton use: for daily activities, exercise, and social interaction. Exoskeleton use during daily activities was the ultimate goal. Therefore, the future exoskeleton should be: easy to use, small and lightweight, tailor made, safe, comfortable, less distinctive, durable, and affordable. Improving the ease of use was relevant for all purposes, for all participants. The other suggestions for improvement varied depending on the purpose of use and the participant. Conclusions: Increasingly more advanced improvements to future exoskeletons are needed to transition from an exercise purpose, to social interaction, and ultimately use during daily activities. In the current study, detailed suggestions for improvements from experienced exoskeleton users have been made. Only when multiple of these suggestions are adjusted, can the exoskeleton be used to its full potential.

Previous research showed that an Inertial Measurement Unit (IMU) on the anterior side of the shank can accurately measure the Shank-to-Vertical Angle (SVA), which is a clinically-used parameter to guide tuning of ankle-foot orthoses (AFOs). However, in this context it is specifically important that differences in the SVA are detected during the tuning process, i.e., when adjusting heel height. This study investigated the validity of the SVA as measured by an IMU and its responsiveness to changes in AFO-footwear combination (AFO-FC) heel height in persons with incomplete spinal cord injury (iSCI). Additionally, the effect of heel height on knee flexion-extension angle and internal moment was evaluated. Twelve persons with an iSCI walked with their own AFO-FC in three different conditions: (1) without a heel wedge (refHH), (2) with 5 mm heel wedge (lowHH) and (3) with 10 mm heel wedge (highHH). Walking was recorded by a single IMU on the anterior side of the shank and a 3D gait analysis (3DGA) simultaneously. To estimate validity, a paired t-test and intraclass correlation coefficient (ICC) between the SVAIMU and SVA3DGA were calculated for the refHH. A repeated measures ANOVA was performed to evaluate the differences between the heel heights. A good validity with a mean difference smaller than 1 and an ICC above 0.9 was found for the SVA during midstance phase and at midstance. Significant differences between the heel heights were found for changes in SVAIMU (p = 0.036) and knee moment (p = 0.020) during the midstance phase and in SVAIMU (p = 0.042) and SVA3DGA (p = 0.006) at midstance. Post-hoc analysis revealed a significant difference between the ref and high heel height condition for the SVAIMU (p = 0.005) and knee moment (p = 0.006) during the midstance phase and for the SVAIMU (p = 0.010) and SVA3DGA (p = 0.006) at the instant of midstance. The SVA measured with an IMU is valid and responsive to changing heel heights and equivalent to the gold standard 3DGA. The knee joint angle and knee joint moment showed concomitant changes compared to SVA as a result of changing heel height.

Contains fulltext : 225521.pdf (Publisher’s version ) (Open Access) A consequence of a complete spinal cord injury (SCI) is the loss of gait capacity. Wearable exoskeletons for the lower extremity enable household and community ambulation in people with SCI. This study assessed the amount, purpose, and location of exoskeleton use in the home and community environment, without any restrictions. The number of steps taken was read from the exoskeleton software. Participants kept a daily logbook, and completed two user experience questionnaires (Quebec User Evaluation of Satisfaction with assistive Technology (D-QUEST) and System Usability Scale (SUS)). Fourteen people with a complete SCI used the ReWalk exoskeleton a median of 9 (range [1-15]) out of 16 ([12-21]) days, in which participants took a median of 3,226 ([330-28,882]) steps. The exoskeleton was mostly used for exercise purposes (74%) and social interaction (20%). The main location of use was outdoors (48%). Overall, participants were satisfied with the exoskeleton (D-QUEST 3.7 ± 0.4) and its usability (SUS 72.5 [52.5-95.0]). Participants with complete SCI report satisfaction with the exoskeleton for exercise and social interaction in the home and community, but report limitations as an assistive device during daily life.

Many Cerebral Vascular Accident (CVA) patients suffer from gait and balance problems, which have a large impact on daily functioning. During clinical rehabilitation, a multidisciplinary team uses advanced training facilities to help patients regain optimal function. After discharge, however, CVA patients have difficulty to continue training to improve or even maintain their perceived functioning level. One of the limitations of at home training is that patients do not receive any feedback on their performance and progress. Feedback on the execution is important in CVA patients because sensorimotor feedback is disturbed. Moreover, feedback on the progress of their functioning level keeps the patients motivated. Within our project "Movin(g) Reality" we are developing two patterns: Train@Home, and Train2Go in addition to the already existing pattern Train@TheClinic.

Data reduction techniques are commonly applied to dynamic plantar pressure measurements, often prior to the measurement’s analysis. In performing these data reductions, information is discarded from the measurement before it can be evaluated, leading to unkonwn consequences. In this study, we aim to provide the first assessment of what impact data reduction techniques have on plantar pressure measurements. Specifically, we quantify the extent to which information of any kind is discarded when performing common data reductions. Plantar pressure measurements were collected from 33 healthy controls, 8 Hallux Valgus patients, and 10 Metatarsalgia patients. Eleven common data reductions were then applied to the measurements, and the resulting datasets were compared to the original measurement in three ways. First, information theory was used to estimate the information content present in the original and reduced datasets. Second, principal component analysis was used to estimate the number of intrinsic dimensions present. Finally, a permutational multivariate ANOVA was performed to evaluate the significance of group differences between the healthy controls, Hallux Valgus, and Metatarsalgia groups. The evaluated data reductions showed a minimum of 99.1% loss in information content and losses of dimensionality between 20.8% and 83.3%. Significant group differences were also lost after each of the 11 data reductions (alpha = 0.05), but these results may differ for other patient groups (especially those with highly-deformed footprints) or other region of interest definitions. Nevertheless, the existence of these results suggest that the diagnostic content of dynamic plantar pressure measurements is yet to be fully exploited., This research has received funding from the European Union's Horizon 2020 reserch and innovation programme under the Marie Sklodowska-Curie grant agreement no. 746614.

Item does not contain fulltext BACKGROUND CONTEXT: Patients with adolescent idiopathic scoliosis (AIS) perform surprisingly well after spinal correction and fusion. It was previously hypothesized that, during gait, certain mechanisms compensate for the loss in spinal motion. Still, previous studies could not identify such compensatory mechanisms in the lower body. PURPOSE: This study aims to test the hypothesis of a compensatory increased motion of the distal unfused part of the spine during gait after posterior spinal correction and fusion. STUDY: This is a prospective gait study. PATIENTS AND METHODS: Twelve patients with AIS were included. Sets of three VICON skin markers were used to measure the 3D motion of the proximal part of the fusion in relation to the pelvis (PFP) and the distal part of the fusion in relation to the pelvis (DFP). By doing so, PFP represents the motion of the fused and unfused parts of the spine, and DFP represents the motion of the unfused part of the spine. Measurements were performed preoperatively and 3 and 12 months after posterior spinal correction and fusion. RESULTS: Surgery resulted in a decrease in PFP transversal plane range of motion (ROM) (8.3 degrees vs. 5.9 degrees , p=.006). No compensatory increase in the ROM of DFP could be identified. Actually, DFP transversal plane ROM also decreased (8.2 degrees vs. 5.6 degrees , p=.019). No improvement over time was observed when comparing the 3- and 12-month postoperative measurements. CONCLUSIONS: The hypothesis of a compensatory increase in motion of the distal unfused segments after spinal fusion for AIS is a much researched and controversial topic. This study is the first to study this hypothesis in such detail during gait and could not demonstrate such increase. 01 december 2018

Background Wearable exoskeletons can be a powerful tool for the facilitation of ambulation of complete Spinal Cord Injury (SCI) subjects, which has several psychological and physical advantages. However, exoskeleton control is difficult for this group of users and requires a long period of training. People with SCI not only lack the motor control, but also miss the sensory information from below the level of the lesion, which is for example very important in their perception of body posture and makes balancing with an exoskeleton difficult. It is hypothesized that through sensory substitution part of the missing sensory information can be provided and might thereby improve the control of an exoskeleton. However, it is not known which information would be most important to receive while using an exoskeleton and how this feedback should be provided. Methods To investigate the preferences of users of an exoskeleton, a questionnaire was filled out by 10 SCI subjects who underwent a training program with a commercial exoskeleton (ReWalk). The questionnaire consisted of questions about the use of the exoskeleton to identify which information is missing and which instructions from the therapists were needed to be able to control the exoskeleton. The second part of the questionnaire focused on the possibilities of sensory feedback and preferences for stimulation methods (auditory, vibrotactile or visual) and feedback timing (discrete or continuous) were investigated. Furthermore, six options for feedback parameters (step initiation, continuous and discrete gait phases, foot position and mediolateral and anteroposterior weight shift) were proposed and the respondents were asked to indicate their preferences. Results Three feedback parameters (feedback about mediolateral and anteroposterior weight shift and feedback about step initiation) were considered as possibly helpful by the respondents. Furthermore, there were slight preferences for the use of vibrotactile (over auditory and visual) and discrete (over continuous) feedback. Conclusions The answers of the respondents on the optimal feedback parameters were rather variable and therefore it is recommended to let the users choose their preferred feedback system during a training session with several feedback options. However, there are slight preferences for the use of vibrotactile stimulation provided in a discrete way. Electronic supplementary material The online version of this article (10.1186/s12984-018-0445-0) contains supplementary material, which is available to authorized users.

To investigate the effects of posterior spinal fusion (PSF) and curve type on upper body movements in Adolescent Idiopathic Scoliosis (AIS) patients during gait. Twenty-four girls (12–18 years) with AIS underwent PSF. 3D-Gait-analyses were performed preoperatively, at 3 months and 1 year postoperatively. Mean position (0° represents symmetry) and range of motion (ROM) of the trunk (thorax-relative-to-pelvis) in all planes were assessed. Lower body kinematics and spatiotemporal parameters were also evaluated. Mean trunk position improved from 7.0° to 2.9° in transversal plane and from 5.0° to − 0.8° in frontal plane at 3 months postoperative (p

International Federations in Paralympic sport should develop evidence based classification, based on the relative strength of association between impairment and activities that determine sport specific performance. The purpose of the current study was to assess the relationship between trunk strength impairment and three activities that determine performance in Wheelchair Rugby, and to determine whether this relationship supports the concept of “natural classes”. Trunk muscle strength and three determinants of performance were assessed in 27 athletes The correlations between lateral trunk muscle strength and the determinant tilting the chair, and between forward trunk muscle strength and the determinants 1 m acceleration and sprint momentum were calculated. To group athletes based on impairment, K-means cluster analysis was used to group athletes according to how much trunk muscle strength affected the activities. There were significant, moderate to strong correlations between left-right strength and chair tilting (r = .50), between forward strength and 1 m acceleration (r = .59) and between forward strength and sprint momentum (r = .79). Cluster analysis indicated at least one cut-point in performance with a decrease in impairment in all three wheelchair activities, supporting the concept of “natural classes”. This article is protected by copyright. All rights reserved.

The Shank-to-Vertical Angle (SVA) is a commonly used parameter to describe orthotic alignment. 3D gait analysis (3DGA) or 2D video analysis are usually used to assess the SVA, but are not always feasible in clinical practice. As an alternative, an Inertial Measurement Unit (IMU) attached and aligned to the shank might be used. This study aimed to investigate the validity, inter-rater reliability and optimal location of a single IMU on the shank to assess the SVA. Thirteen healthy participants (7 m/6f, mean age: 45 ± 18 years) were recorded during quiet standing and barefoot walking using a 3D motion capture system and, simultaneously, with IMUs on the shank. The IMUs were anatomically placed and aligned at two different locations, i.e. anterior, in line with the tibial tuberosity and midline of the ankle (anterior IMU), and lateral, in line with the lateral epicondyle and lateral malleolus (lateral IMU). For each participant, the IMUs were placed by two different researchers. A paired t-test, Bland Altmann analysis (mean difference, repeatability coefficient) and intraclass correlation coefficient (ICC) between the 3DGA and both IMUs, and between raters, was performed. Although validity and reliability of the lateral IMU was low, good validity and inter-rater reliability was found for the anterior IMU (Rater1: mean difference: −0.7 ± 2.1, p = 0.27; ICC = 0.83 and Rater2: mean difference: −0.4 ± 1.9, p = 0.46; ICC = 0.86). Hence, a single IMU placed at the anterior side of the shank is a valid and reliable method to assess the SVA during standing and walking in healthy adults.

Contains fulltext : 229815.pdf (Publisher’s version ) (Closed access) INTRODUCTION: This study investigated the effect of operative claw toe correction with release of the metatarsophalangeal (MTP) joint, repositioning of the plantar fat pad and resection of the proximal interphalangeal joint on foot kinematics, plantar pressure distribution and Foot Function Index (FFI). METHODS: Prospective experimental study with pretest-posttest design. The plantar pressure, 3D foot kinematics and the FFI of 15 patients with symptomatic claw toes were measured three months before and 12months after surgery. Mean pressure, peak pressure and pressure time integral per sensor and various foot angles were calculated for the pre- and posttest and compared to a control group (N=15). RESULTS: Claw toe patients have increased pressure under the distal part of the metatarsal head and less pressure under the proximal part of the metatarsal heads compared to healthy controls. After surgery, there was a redistribution of pressure, resulting in a significant decrease of pressure under the distal part and an increase under the proximal part of the metatarsal head, providing a more equal plantar pressure distribution. Except for some small areas under the forefoot, heel and toes, there were no significant differences in pressure distribution between the operated feet and controls. Small, but significant differences between the pre- and postoperative condition were found for the lateral arch angle, calcaneus/malleolus supination and tibio-talar flexion. The score on the FFI improved statistically significant. DISCUSSION: These findings imply that the present operative procedure results in a more equal distribution of the plantar pressure under the forefoot and decrease of pain and offers successful treatment of metatarsalgia based on claw toe deformity.

Contains fulltext : 218784.pdf (Publisher’s version ) (Open Access) Quantitative analyses of plantar pressure images typically occur at the group level and under the assumption that individuals within each group display homogeneous pressure patterns. When this assumption does not hold, a personalized analysis technique is required. Yet, existing personalized plantar pressure analysis techniques work at the image level, leading to results that can be unintuitive and difficult to interpret. To address these limitations, we introduce PAPPI: the Personalized Analysis of Plantar Pressure Images. PAPPI is built around the statistical modelling of the relationship between plantar pressures in healthy controls and their demographic characteristics. This statistical model then serves as the healthy baseline to which an individual's real plantar pressures are compared using statistical parametric mapping. As a proof-of-concept, we evaluated PAPPI on a cohort of 50 hallux valgus patients. PAPPI showed that plantar pressures from hallux valgus patients did not have a single, homogeneous pattern, but instead, 5 abnormal pressure patterns were observed in sections of this population. When comparing these patterns to foot pain scores (i.e. Foot Function Index, Manchester-Oxford Foot Questionnaire) and radiographic hallux angle measurements, we observed that patients with increased pressure under metatarsal 1 reported less foot pain than other patients in the cohort, while patients with abnormal pressures in the heel showed more severe hallux valgus angles and more foot pain. Also, incidences of pes planus were higher in our hallux valgus cohort compared to the modelled healthy controls. PAPPI helped to clarify recent discrepancies in group-level plantar pressure studies and showed its unique ability to produce quantitative, interpretable, and personalized analyses for plantar pressure images.

Contains fulltext : 215583.pdf (Publisher’s version ) (Closed access) Introduction: Powered robotic exoskeletons are a promising solution to enable standing and walking in patients with spinal cord injury (SCI). Although training and walking with an exoskeleton in motor complete SCI patients is considered safe, the risks of unexpected (technical) adverse events and the risk of fractures are not fully understood. This article reports the occurrence of two different cases of bone fracture during exoskeleton usage. Furthermore, advice is given for extra safety training and instructions. Case presentation: The first case concerns a 47-year-old woman with T12 AIS A SCI. Her exoskeleton shut down unexpectedly probably causing a misalignment of the joints of her lower extremities relative to the joints of the exoskeleton, which resulted in a fracture of her left tibia. The second case involves a 39-year-old man with L1 AIS B SCI. An unexpected fracture of the right distal tibia occurred without a specific prior (traumatic) incident. Discussion: Exoskeleton training instructors, SCI patients and their buddies should be instructed how to handle emergency situations. Furthermore, they should be aware of the risk of stress fractures of the lower extremities. Proper alignment of the exoskeleton relative to the body is of utmost importance to reduce fracture risk. In the case of swelling and discoloring of the skin, radiographic examination should be performed in order to exclude any fracture.

In Paralympic sport, classification of impairment is needed to prevent a one-sided and predictable outcome of competition, in which the least impaired athlete has the best chance to win. To develop evidence-based classification in wheelchair rugby, the impact of trunk impairment, measured by the Trunk Impairment Classification (TIC), on performance-determining activities was assessed. Arm impairment was analyzed as a covariant. Fifty-five athletes, 21 with TIC score 0, 13 with TIC score 0.5, 11 with TIC score 1.0, and 10 with TIC score 1.5 performed standardized sport-specific activities. A multiple step forward regression analysis was performed for all activities to assess the relative impact of trunk and arm impairment on performance. Trunk impairment was the most important factor for tilting the chair and acceleration in the first 2 m. The explained variance of the performance by trunk and arm impairment ranged from 23% for acceleration in the first meter, to 37% for sprint momentum, the tilt test left, and the time to cover 3 and 4 m. This study shows that athletes with limited trunk impairment are more proficient in wheelchair rugby than athletes with severe trunk impairment.

Background: Comparing the dynamic pedobarographic patterns of individuals is common practice in basic and applied research. However, this process is often time-consuming and complex, and commercially available software often lacks powerful visualization and interpretation tools. Methods: We propose a simple method for displaying pixel-level pedobarographic deviations over time relative to a so-called reference pedobarographic pattern. This novel method contains four distinct automated preprocessing stages: 1) normalization of pedobarographic fields (for foot length and width), 2) temporal normalization, 3) a pixel-level z-score–based calculation, and 4) color coding of the normalized pedobarographic fields. Group and patient-level comparisons were illustrated using an experimental data set including diabetic and nondiabetic patients. Results: The automated procedure was found to be robust and quantified distinct temporal deviations in pedobarographic fields. Conclusions: The advantages of the novel method cover several domains, including visualization, interpretation, and education.

Objective Toe walking due to progressive shortening of the calf muscles is common in people with hereditary spastic paraplegia. Achilles tendon lengthening is a treatment option, but clinicians are often hesitant to use this procedure, as it may result in weakening of the calf muscles and, subsequently, in reduced ankle power and knee instability during the stance phase of gait. We report here a case report supporting that these negative side-effects can be avoided in well-selected people with hereditary spastic paraplegia. Method Bilateral Achilles tendon lengthening, combined with bilateral tenotomy of the tibialis posterior and toe flexors, was performed in a 29-year-old woman with uncomplicated hereditary spastic paraplegia who experienced progressive gait instability due to shortening of the soleus and gastrocnemius muscles (resulting in irreducible pes equinus). Results Bilateral Achilles tendon lengthening resulted in improvement in both subjective and objective outcomes. Self-selected gait speed improved from 0.75 m/s before surgery to 1.07 m/s after surgery (p < 0.001). Knee instability during the stance phase did not occur post-surgery. The ankle moment trajectories normalized after surgery, while peak ankle powers increased. Conclusion Correction of bilateral irreducible pes equinus by Achilles tendon lengthening may improve gait capacity in well-selected subjects with hereditary spastic paraplegia. LAY ABSTRACT Toe walking due to shortening of the calf muscles is common in people with hereditary spastic paraplegia. This case report supports that lengthening of the calf muscles (Achilles tendon lengthening) may improve gait in well-selected people with hereditary spastic paraplegia.

Background Gait impairments are common and disabling in chronic stroke patients. Pes equinovarus deformity is one of the primary motor deficits underlying reduced gait capacity after stroke. It predisposes to stance-phase instability and subsequent ankle sprain or falls. This instability is most pronounced when walking barefoot. Tarsal fusion is a recommended treatment option for varus deformity, but scientific evidence is sparse. We therefore evaluated whether a tarsal fusion improved barefoot walking capacity in chronic stroke patients with pes equinovarus deformity. Methods Ten patients with a pes equinovarus deformity secondary to supratentorial stroke underwent surgical correction involving a tarsal fusion of one or more joints. Instrumented gait analysis was performed pre- and postoperatively using a repeated-measures design. Primary outcome measure was gait speed. Results Walking speed significantly improved by 32% after surgery (0.38 m/s ± 0.20 to 0.50 m/s ± 0.17, p = 0.007). Significant improvement was also observed when looking at cadence (p = 0.028), stride length (p = 0.016), and paretic step length (p = 0.005). Step length on the nonparetic side did not change. Peak ankle moment increased significantly on the nonparetic side (p = 0.021), but not on the paretic side (p = 0.580). In addition, functional ambulation scores increased significantly (p = 0.008), as did satisfaction with gait performance (p = 0.017). Conclusions Tarsal fusion for equinovarus deformity in chronic stroke patients improves gait capacity, and the degree of improvement is of clinical relevance. Our results suggest that the improved gait capacity may be related to better prepositioning and loading of the paretic foot, leading to larger paretic step length and nonparetic ankle kinetics.

Item does not contain fulltext BACKGROUND: Despite impressive results of the pharmacological management of rheumatoid arthritis, still certain patients suffer from rheumatoid forefoot problems. Surgical treatment of these forefoot deformities can be an option. In literature no high-quality studies on this topic can be found. The goal of present study is to compare the results of a metatarsal head (MTH) resecting technique with a MTH preserving technique in the operative treatment of severe rheumatoid forefoot deformity. METHODS: Patients suffering from well-defined rheumatoid forefoot deformity were prospectively enrolled in three institutions. This non-blinded study had a randomised clinical design and eligible patients were randomly assigned to undergo either resection of preservation of the MTH. The primary outcome measure consisted of the AOFAS score. Secondary outcome measures were: the FFI, the VAS for pain and the SF-36. RESULTS: Twenty-three patients (10 in MTH preservation group) were included and analysed. After one year follow-up no significant differences in AOFAS score and additional outcome factors were found. A total of 10 complications in 23 patients were reported. CONCLUSIONS: This randomised clinical study did not show significant clinical difference between a MTH resecting and a preserving procedure in patients suffering from rheumatoid forefoot deformity. Both procedures resulted in considerable improvement of pain and activity scores.

Item does not contain fulltext Trunk coordination is essential for many activities of daily living in wheelchair users. This study investigated whether Fitts' law is applicable to trunk movements in a sitting position. Fourteen healthy adults performed two series of 24 tasks of trunk flexion-extension movements in a sitting position. The results showed significant linear relationships between average group movement time (MT) and index of difficulty (ID) over all tasks (r(2) = 0.92) and within target distances (0.94 < r(2) < 1.00). Target distance affected intercept and slope (P < 0.001). Hence, Fitts' law is applicable to the studied trunk movements in a sitting position, indicating these trunk movements tasks could serve as a basis for qualitative trunk coordination tests. Transferability of these conclusions to wheelchair users, and optimal test design should be further investigated.

Background Pedobarography produces large sets of plantar pressure samples that are routinely subsampled (e.g. using regions of interest) or aggregated (e.g. center of pressure trajectories, peak pressure images) in order to simplify statistical analysis and provide intuitive clinical measures. Research question We hypothesize that these data reductions discard gait information that can be used to differentiate between groups or conditions. Methods To test the hypothesis of null information loss, we created an implementation of statistical parametric mapping (SPM) for dynamic plantar pressure datasets (i.e. plantar pressure videos). Our SPM software framework brings all plantar pressure videos into anatomical and temporal correspondence, then performs statistical tests at each sampling location in space and time. Novelly, we introduce non-linear temporal registration into the framework in order to normalize for timing differences within the stance phase. We refer to our software framework as STAPP: spatiotemporal analysis of plantar pressure measurements. Using STAPP, we tested our hypothesis on plantar pressure videos from 33 healthy subjects walking at different speeds. Results As walking speed increased, STAPP was able to identify significant decreases in plantar pressure at mid-stance from the heel through the lateral forefoot. The extent of these plantar pressure decreases has not previously been observed using existing plantar pressure analysis techniques. Significance We therefore conclude that the subsampling of plantar pressure videos – a task which led to the discarding of gait information in our study – can be avoided using STAPP., This research has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 746614.

Background: It is unclear whether proximal interphalangeal joint (PIPJ) resection or fusion leads to superior clinical outcome in patients undergoing hammertoe surgery. The purpose of this study was to prospectively evaluate a series of patients undergoing this surgery. Methods: Patients with one or more toes with rigid PIP flexion deformity were prospectively enrolled. These patients were randomly assigned to undergo either PIPJ resection or PIPJ fusion. In addition to the PIPJ procedure, a metatarsophalangeal joint (MTPJ) release was performed if deemed necessary. Follow-up was up to 1 year postoperatively. Twenty-six patients (39 toes) were included in the PIPJ resection group and 29 (50 toes) in the PIPJ fusion group. Results: Thirty-four underwent an MTPJ release. No significant difference in foot outcome scores (American Orthopaedic Foot & Ankle Society scale, the Foot Function Index, and visual analog scale pain) could be detected after 1-year follow-up. A statistically significant difference was found regarding the toe alignment in the sagittal plane in favor of PIPJ fusion. Conclusions: Our randomized controlled study did not show any clinical outcome difference between PIPJ fusion and PIPJ resection. Both procedures resulted in good to excellent outcome in pain and activity scores. Level of Evidence: Level II, lesser quality RCT or prospective comparative study.

Study aim: To investigate differences in the center of pressure (COP) during gait and single leg stance between subjects with persistent complaints (PC) and without persistent complaints (NPC) after a lateral ankle sprain. Methods: 44 patients who consulted the general practitioner, 6-12 months prior to inclusion, with a lateral ankle sprain were included for the current study purpose. Using a 7-point Likert scale patients were divided into the PC or NPC group. All subjects filled out an online questionnaire, walked along a walkway and performed a single leg stance, both on the RSscan. Primary outcomes included the COP displacement, range and percentage used in mediolateral and anterioposterior direction. Results: There was a trend (p < 0.05) towards a more medially COP trajectory during walking at 34-46% and 83-96% and more anteriorly at 21-31% and 91-100% of the stance phase in the PC group compared to NPC group. Additionally, the COP was more laterally located in the sprained leg compared to the non-sprained leg in the PC group in the loading response phase (p < 0.05). An interaction was found for the percentage of anterior-posterior range used in single leg stance without vision. Conclusion: The COP trajectory discriminates between patients with PC and NPC. This indicates that roll off during gait might play an important role in the recovery of patients after a lateral ankle sprain and could be used to monitor treatment. (C) 2016 Elsevier B.V. All rights reserved.

The authors regret to have included an incorrect panel of Fig. 1 to the manuscript. In Fig. 1, the bottom right panel (pelvis, transversal plane) has an incorrect colour setting. Line colour and line type should represent measurement time (pre-operative, 3 months post-operative, and 12 months post-operative) and walking speed (0.45, 1.35, and 2.22 m/s) respectively. Unfortunately, for the bottom right panel these settings were accidently interchanged. The results section was written with the use of a correct figure and thus the conclusion of the study remains the same. The correct version of Fig. 1 is attached to this corrigendum. [figure-presented] The authors would like to apologise for any inconvenience caused.

Item does not contain fulltext Previous gait analysis studies of patients with an ankle arthrodesis have reported increased motion in the adjacent joints. However, of similar importance are the forces that act on the ipsi- and contralateral joints and the effect of ankle arthrodesis with regard to balance control. The purpose of the present study was to determine the joint moments and the amount of asymmetrical loading of the ankle and joints adjacent to the ankle in patients after successful ankle arthrodesis. Therefore, 8 patients with a painless ankle fusion were included and assessed using 4 functional tests: preferred and fast speed walking, a sit-to-stand test, and a balance test. The ground reaction force and ankle joint moment were smaller in the fused ankle. During the balance on foam test, the velocity of the center of pressure was significantly larger on the contralateral extremity. In conclusion, ankle arthrodesis leads to small asymmetries in joint moments during gait, indicating greater loading of the contralateral ankle. In addition, the unaffected leg compensates for the operated leg in balance control. Because of the small alterations, overuse of the contralateral ankle is not expected after ankle arthrodesis.

Ankle arthrodesis provides satisfactory functional outcome based on basic daily activities, but information regarding more demanding tasks is limited. Also, studies reporting longer term survival and complication rates are sparse and concern small study populations. This study reports functional outcome with more focus on demanding tasks and sports and reports the mid- to long-term union and complication rates in a large study population.Between 2005 and 2010, an ankle arthrodesis was performed on 185 ankles. Clinical results were retrospectively assessed with the Foot Function Index (FFI), visual analog scale (VAS) for pain, and the Foot and Ankle Ability Measure (FAAM). Information regarding sports pre- and postoperatively was obtained through a questionnaire. In addition, postoperative complications, reoperations, and failures (defined as nonunion of the ankle arthrodesis) were determined. Mean follow-up time was 8 years.FFI scores significantly improved, the FAAM ADL score was 70%, and the mean VAS for pain at the ankle/hindfoot at follow-up was 20. Sports participation slightly diminished from 79.5% prior to the onset of disabling complaints to 68.9% postoperatively. Of the patients, 73.1% were able to hike with a median hiking time of 40 minutes (range, 2-600 minutes). Kneeling could be performed on average 10 minutes (range, 2-60 minutes) in 39.8% and jumping down from steps by 23.5% of the patients. A small selection of patients was able to sprint (14%), and 16.8% of the patients were able to run a median distance of 60 meters (range, 3-1000 meters). Failure occurred in 9.2% and other postoperative complications were present in 21.6%, requiring reoperation in 8.6% of the cases.Ankle arthrodesis led to satisfactory functional outcome and pain reduction. Most patients remained active in sports, but a transition to less demanding sporting activities was seen. The complication and failure rates were similar with previous literature, and the incidence of nonrevision secondary surgery was relatively low.Level III, retrospective comparative study.

Item does not contain fulltext INTRODUCTION: Based on the windlass mechanism theory of Hicks, the medial longitudinal arch (MLA) flattens during weight bearing. Simultaneously, foot lengthening is expected. However, changes in foot length during gait and the influence of walking speed has not been investigated yet. METHODS: The foot length and MLA angle of 34 healthy subjects (18 males, 16 females) at 3 velocities (preferred, low (preferred -0.4 m/s) and fast (preferred +0.4 m/s) speed were investigated with a 3D motion analysis system (VICON((R))). The MLA angle was calculated as the angle between the second metatarsal head, the navicular tuberculum and the heel in the local sagittal plane. Foot length was calculated as the distance between the marker at the heel and the 2nd metatarsal head. A General Linear Model for repeated measures was used to indicate significant differences in MLA angle and foot length between different walking speeds. RESULTS: The foot lengthened during the weight acceptance phase of gait and shortened during propulsion. With increased walking speed, the foot elongated less after heel strike and shortened more during push off. The MLA angle and foot length curve were similar, except between 50% and 80% of the stance phase in which the MLA increases whereas the foot length showed a slight decrease. CONCLUSION: Foot length seems to represent the Hicks mechanism in the foot and the ability of the foot to bear weight. At higher speeds, the foot becomes relatively stiffer, presumably to act as a lever arm to provide extra propulsion. 5 p.

Observational, cross-sectional. A new classification system for trunk impairment in wheelchair rugby was introduced in 2010. It consists of 10 tests, arranged in an algorithm, to assign four different trunk scores (0, 0.5, 1.0 or 1.5) to athletes. The purpose of this study was to assess the inter-rater reliability of this classification system. National competition for wheelchair rugby and wheelchair basketball in the Netherlands and Belgium. Three experienced wheelchair rugby classifiers independently assigned trunk scores to wheelchair rugby and wheelchair basketball athletes in two sessions. After each session, test descriptions were adjusted. The inter-rater reliability was evaluated by determining the agreement and Fleiss Kappa. In the first session, all classifiers agreed on the trunk score in 13 out of 16 athletes; the overall Kappa was 0.76 (P

Background Plantar pressure is widely used to evaluate foot complaints. However, most plantar pressure studies focus on the symptomatic foot with foot deformities. The purposes of this study were to investigate subjects without clear foot deformities and to identify differences in plantar pressure pattern between subjects with and without forefoot pain. The second aim was to discriminate between subjects with and without forefoot pain based on plantar pressure measurements using neural networks. Methods In total, 297 subjects without foot deformities of whom almost 50% had forefoot pain walked barefoot over a pressure plate. Foot complaints and subject characteristics were assessed with a questionnaire and a clinical evaluation. Plantar pressure was analyzed using a recently developed method, which produced pressure images of the time integral, peak pressure, mean pressure, time of activation and deactivation, and total contact time per pixel. After pre-processing the pressure images with principal component analysis, a forward selection procedure with neural networks was used to classify forefoot pain. Findings The pressure–time integral and mean pressure were significantly larger under the metatarsals II and III for subjects with forefoot pain. A neural network with 14 input parameters correctly classified forefoot pain in 70.4% of the test feet. Interpretation The differences in plantar pressure parameters between subjects with and without forefoot pain were small. The reasonable performance of forefoot pain classification by neural networks suggests that forefoot pain is related more to the distribution of the pressure under the foot than to the absolute values of the pressure at fixed locations.

Objectives Anterior Cruciate Ligament (ACL) deficiency may result in abnormal lower limb loading with increased foot pronation. This study evaluated spatiotemporal parameters and plantar pressure distribution during walking in participants with and without an ACL rupture. Design Cross-sectional. Methods Plantar pressure was measured in 42 unilateral ACL deficient (ACLD) participants and 32 healthy controls while walking barefoot. Spatiotemporal parameters, pressure distribution and center of pressure (CoP) during foot roll off were determined. Differences in spatiotemporal parameters and pressure distribution were analyzed using a Linear Mixed Model. CoP position was analyzed with one-way ANOVA. Results ACLD participants had a longer contact time and earlier forefoot contact compared to controls. The ACLD side showed a shorter contact time and a faster roll off toward the forefoot compared to the ACL intact side. Compared to controls, ACLD participants had increased pressure under the medioproximal side of the midfoot. Within ACLD participants, the ACLD side had decreased pressure under the heel and increased pressure under the forefoot. Foot pronation was not different between groups or within ACLD participants. CoP of the ACLD participants was significantly more toward the toes during initial contact and toward the heel during foot flat. Conclusions Changes in lower limb loading during barefoot walking in ACLD participants are due to changes in roll off pattern, most likely in order to reduce anterior shear forces on the knee. Dynamic plantar pressure measurements may assist in evaluating and guiding interventions aimed at normalizing lower limb and knee biomechanics in ACL deficiency.

Item does not contain fulltext INTRODUCTION: Previous studies show a limited alteration of gait at normal walking speed after spinal fusion surgery for adolescent idiopathic scoliosis (AIS), despite the presumed essential role of spinal mobility during gait. This study analyses how spinal fusion affects gait at more challenging walking speeds. More specifically, we investigated whether thoracic-pelvic rotations are reduced to a larger extent at higher gait speeds and whether compensatory mechanisms above and below the stiffened spine are present. METHODS: 18 AIS patients underwent gait analysis at increasing walking speeds (0.45 to 2.22m/s) before and after spinal fusion. The range of motion (ROM) of the upper (thorax, thoracic-pelvic and pelvis) and lower body (hip, knee and ankle) was determined in all three planes. Spatiotemporal parameters of interest were stride length and cadence. RESULTS: Spinal fusion diminished transverse plane thoracic-pelvic ROM and this difference was more explicit at higher walking speeds. Transversal pelvis ROM was also decreased but this effect was not affected by speed. Lower body ROM, step length and cadence remained unaffected. DISCUSSION: Despite the reduction of upper body ROM after spine surgery during high speed gait, no altered spatiotemporal parameters or increased compensatory ROM above or below the fusion (i.e. in the shoulder girdle or lower extremities) was identified. Thus, it remains unclear how patients can cope so well with such major surgery. Future studies should focus on analyzing the kinematics of individual spinal levels above and below the fusion during gait to investigate possible compensatory mechanisms within the spine.

Contains fulltext : 182304.pdf (Publisher’s version ) (Open Access) PURPOSE: In this prospective study, the changes in kinetics and kinematics of gait and clinical outcomes after a varus osteotomy (tibial, femoral or double osteotomy) in patients with osteoarthritis (OA) of the knee and a valgus leg alignment were analysed and compared to healthy subjects. METHODS: Twelve patients and ten healthy controls were included. Both kinetics and kinematics of gait and clinical and radiographic outcomes were evaluated. RESULTS: The knee adduction moment increased significantly postoperatively (p < 0.05) and almost similar to the control group. Patients showed less knee and hip flexion/extension motion and moment during gait pre- and postoperatively compared to the controls. A significant improvement was found in WOMAC [80.8 (SD 16.1), p = 0.000], KOS [74.9 (SD 14.7), p = 0.018], OKS [21.2 (SD 7.5), p = 0.000] and VAS-pain [32.9 (SD 20.9), p = 0.003] in all patients irrespective of the osteotomy technique used. The radiographic measurements showed a mean hip knee ankle (HKA) angle correction of 10.4 degrees (95 % CI 6.4 degrees -14.4 degrees ). CONCLUSION: In patients with knee OA combined with a valgus leg alignment, the varus-producing osteotomy is a successful treatment. Postoperatively, the patients showed kinetics and kinematics of gait similar as that of a healthy control group. A significant increase in the knee adduction moment during stance phase was found, which was related to the degree of correction. The HKA angle towards zero degrees caused a medial shift in the dynamic knee loading. The medial shift will optimally restore cartilage loading forces and knee ligament balance and reduces progression of OA or the risk of OA. A significant improvement in all clinical outcomes was also found. LEVEL OF EVIDENCE: III. 10 p.

Objective: To gain insight into the relationship between activity pacing and physical inactivity. Design: A cross-sectional study. Setting: Outpatient clinic of a rheumatology department. Subjects: Men and women diagnosed with rheumatoid arthritis Main measures: Physical activity was assessed using self-reported measures and an accelerometer-based activity monitor. An occupational therapist and specialized nurse analysed the self-reported physical activity data and classified on the basis of consensus the pacing of activities of all patients as ‘adequate’ or ‘not adequate’. Results: Thirty rheumatoid arthritis patients participated in this study of whom nine were categorized as adequate activity pacers. None of these nine undertook sufficient exercise whereas 6 of the 20 people who did not pace activity appropriately did. Physical activity levels assessed by self-reported measures were significantly higher than when assessed by an accelerometer-based activity monitor. Conclusions: Activity pacing was associated with lower levels of physical activity. Since patients with rheumatoid arthritis are already at risk for inactivity, further inactivation by activity pacing might potentially be harmful.

Background:Metatarsal pads are frequently prescribed for patients with metatarsalgia to reduce pain under the distal metatarsal heads. Several studies showed reduced pain and reduced plantar pressure just distal to the metatarsal pad. However, only part of the pain reduction could be explained by the decrease in plantar pressure under the forefoot. Therefore, an alternative hypothesis is proposed that pain relief is related to a widening of the foot and the creation of extra space between the metatarsal heads. This study focused on the effect of a metatarsal pad on the geometry of the forefoot by studying forefoot width and the height of the second metatarsal head.Methods:Using a motion analysis system, 16 primary metatarsalgia feet and 12 control feet were measured when walking with and without a metatarsal pad.Results:A significant mean increase of 0.60 mm in forefoot width during the stance phase was found when a metatarsal pad was worn. During midstance, the mean increase in forefoot width was 0.74 mm. In addition, walking with a metatarsal pad revealed an increase in the height of the second metatarsal head (mean, 0.62 mm). No differences were found between patients and controls.Conclusions:The combination of increased forefoot width and the height of the second metatarsal head produced by the metatarsal pad results in an increase in space between the metatarsal heads. This extra space could play a role in pain reduction produced by a metatarsal pad. (J Am Podiatr Med Assoc 102(1): 18–24, 2012)

De pelotte wordt vaak ingezet om pijn onder de voorvoet te bestrijden. Dit heeft meestal succes, maar het werkingsmechanisme is nog niet geheel duidelijk. Recentelijk heeft de Sint Maartenskliniek wetenschappelijk onderzoek verricht naar de werking van de pelotte. Daaruit blijkt dat de pelotte naast drukvermindering onder de voorvoet ook zorgt voor een extra verbreding van de voorvoet tijdens het lopen wat de pijnvermindering mogelijk kan verklaren.

Femoral component rotation is believed to be one of the factors influencing patellar tracking behavior. With the balanced gap implantation technique, the rotation of the femoral component can vary as it is guided by the ligaments. This study investigated whether femoral component rotation influenced patella position after primary total knee replacement (TKR).In this prospective cohort study, a primary TKR was implanted in 49 patients using a balanced gap technique and a CT-free navigation system. Femoral component rotation was measured using the navigation data of the distal femur cut, referenced from the posterior condyles. At the 2-year follow-up, lateral patellar tilt and patellar displacement were measured on axial patella radiographs. Logistic regression analysis on femoral component rotation and preoperative patella position was conducted to identify predictors for postoperative patellar tilt and displacement.Femoral component rotation that varied between -3 and 12° exorotation was not a predictor for postoperative tilt and displacement. Only preoperative displacement significantly predicted patella displacement.Although the balanced gap implantation technique resulted in a wide inter-patient variability for femoral component rotation, this variable rotation was not found to be associated with abnormal patellar position. Preoperative displacement results in a higher risk at a postoperatively displaced patella. The balanced gap technique can safely be used without an elevated risk for patella malposition.

Contains fulltext : 96387.pdf (Publisher’s version ) (Closed access) Near-infrared spectroscopy (NIRS) is a non-invasive optical imaging technique, which is increasingly used to measure hemodynamic responses in the motor cortex. The location at which the NIRS optodes are placed on the skull is a major factor in measuring the hemodynamic responses optimally. In this study, the validity of using transcranial magnetic stimulation (TMS) in combination with a 3D motion analysis system to relocate the TMS derived position was tested. In addition, the main goal was to quantify the advantage of using TMS to locate the optimal position in relation to the most commonly used EEG C3 position. Markers were placed on the TMS coil and on the head of the subject. In eleven subjects, a TMS measurement was performed to determine the individual motor-evoked potential center-of-gravity (MEP-CoG). This procedure was repeated in nine subjects to test the validity. Subsequently, hemodynamic responses were measured at the MEP-CoG position and at the C3 position during a thumb abduction and adduction task. On average, the MEP-CoG location was located 19.2mm away from the C3 position. The reproducibility study on the MEP-CoG relocation procedure revealed no systematic relocations. No differences in early and delayed hemodynamic responses were found between the C3 and MEP-CoG position. These results indicate that using TMS for NIRS optodes positioning on the motor cortex does not result in higher hemodynamic response amplitudes. This could be explained if NIRS and TMS assess slightly different functions.

Item does not contain fulltext Importance: Gait impairments are common in patients with chronic supratentorial upper motor neuron lesions and are a source of disability. Clinical management aimed at improving the gait pattern in these patients is generally perceived as a challenging task because many possible abnormalities may interact. Moreover, a multitude of treatment options exist, ranging from assistive devices and muscle stretching to pharmacologic and surgical interventions, but evidence is inconclusive for most approaches and clear treatment guidelines are lacking. Observations: Gait deviations in adults with a chronic supratentorial upper motor neuron lesion can approximately be reduced to the following 3 groups of primary deficits: (1) imbalance of muscle strength, length, and activity around the ankle and tarsal joints leading to pes equinovarus or pes equinus; (2) calf muscle weakness; and (3) overactivity of proximal leg muscles. Conclusions and Relevance: A stepwise treatment algorithm emphasizes medical-technical interventions, which are based on evidence when available and otherwise reflect practice-based experience.

Contains fulltext : 89748.pdf (Publisher’s version ) (Closed access) PURPOSE: The popularity of long-distance walking (LDW) has increased in the last decades. However, the effects of LDW on plantar pressure distribution and foot complaints, in particular, after several days of walking, have not been studied. METHODS: We obtained the plantar pressure data of 62 subjects who had no history of foot complaints and who walked a total distance of 199.8 km for men (n = 30) and 161.5 km for women (n = 32) during four consecutive days. Plantar pressure was measured each day after the finish (posttests I-IV) and compared with the baseline plantar pressure data, which was obtained 1 or 2 d before the march (pretest). Mean, peak, and pressure-time integral per pixel as well as the center of pressure (COP) trajectory of each foot per measurement day were calculated using the normalization method of Keijsers et al. A paired t-test with an adjusted P value was used to detect significant differences between pretest and posttest. RESULTS: Short-term adjustment to LDW resulted in a significant decreased loading on the toes accompanied with an increased loading on the metatarsal head III-V (P < 0.001). At all stages, particularly at later stages, there was significantly more heel loading (P < 0.001). Furthermore, the COP significantly displaced in the posterior direction but not in the mediolateral direction after marching. Contact time increased slightly from 638.5 +/- 24.2 to 675.4 +/- 22.5 ms (P < 0.001). CONCLUSIONS: The increased heel loading and decreased function of the toes found after marching indicate a change of walking pattern with less roll-off. It is argued that these changes reflect the effect of fatigue of the lower leg muscles and to avoid loading of the most vulnerable parts of the foot. 01 december 2010

This prospective study investigated whether ligament releases necessary during total knee replacement (TKR) led to a higher varus-valgus laxity during intraoperative examination after implantation of the prosthesis and after 6 months. The laxity values of TKR patients were also compared to healthy controls. Varus-valgus laxity was assessed intra- and postoperatively in extension and 70 degrees flexion in 49 patients undergoing TKR, implanted using a balanced gap technique. Knees were catalogued according to ligament releases performed during surgery. Postoperative varus-valgus laxity and laxity after 6 months had not increased following release of the posteromedial capsule, iliotibial tract, and the superficial medial collateral ligament. The obtained postoperative laxity compares well with a healthy equally aged control group. It can be concluded that the balanced gap technique results in stable knees and that releases can safely be performed to achieve neutral leg alignment without causing postoperative laxity.

Aims The concept of ‘classification’ has, similar to many other diseases, been found to be fundamental in the field of diabetic medicine. In the current study, we aimed at determining efficacy measures of a recently published plantar pressure based classification system. Methods Technical efficacy of the classification system was investigated by applying a high resolution, pixel-level analysis on the normalized plantar pressure pedobarographic fields of the original experimental dataset consisting of 97 patients with diabetes and 33 persons without diabetes. Clinical efficacy was assessed by considering the occurence of foot ulcers at the plantar aspect of the forefoot in this dataset. Classification efficacy was assessed by determining the classification recognition rate as well as its sensitivity and specificity using cross-validation subsets of the experimental dataset together with a novel cohort of 12 patients with diabetes. Results Pixel-level comparison of the four groups associated to the classification system highlighted distinct regional differences. Retrospective analysis showed the occurence of eleven foot ulcers in the experimental dataset since their gait analysis. Eight out of the eleven ulcers developed in a region of the foot which had the highest forces. Overall classification recognition rate exceeded 90% for all cross-validation subsets. Sensitivity and specificity of the four groups associated to the classification system exceeded respectively the 0.7 and 0.8 level in all cross-validation subsets. Conclusions The results of the current study support the use of the novel plantar pressure based classification system in diabetic foot medicine. It may particularly serve in communication, diagnosis and clinical decision making.