[An update on clinical gait analysis : Current developments and applications]. / Update klinische Ganganalyse : Aktuelle Entwicklungen und Einsatzmöglichkeiten.

The objective acquisition and assessment of joint movements and loads using instrumented gait analysis has become an established tool in clinical diagnostics. In particular, marker-based 3D gait analyses make use of an increasingly comprehensive database for the assessment of orthopaedic or neurological questions. Based on this data and medical-scientific experience, increasingly reliable approaches and evaluation strategies are emerging, which also draw on methods from artificial intelligence and musculoskeletal modelling. This article focusses on marker-based gait analyses of the lower extremity (hip, knee, foot) and how these can be used in a clinically relevant way using current methods, e.g. for determining indications or optimization of surgical planning. Finally, current developments and applications by using alternative methods from sensor technology and optical motion capture will be briefly discussed.

Influence of quality of reduction using radiological criteria on kinematics and kinetics in ankle fractures with unstable syndesmotic injury.

BACKGROUND: In ankle fractures with syndesmotic injury, the anatomic reduction of the ankle mortise is crucial for preventing osteoarthritis. Yet, no studies have analysed the effect of surgical reduction after unstable ankle fractures on patients' active functional outcome. METHODS: The Intraoperative 3D imaging data of patients surgically treated between 2012 and 2019 for ankle fracture with concomitant syndesmotic injury were reviewed. 58 patients were allocated to two groups depending on whether the criteria for radiologically optimal reduction were met (39 patients) or not (19 patients). Criteria for optimal reduction were composed of objectively measured and subjectively rated data. After undertaking the Olerud/Molander ankle score, a gait analysis and several active function tests using 3D motion capture were performed in order to evaluate kinetic and kinematic differences between both groups. FINDINGS: Patients showed deficits of range of motion and balance parameters on the injured ankle, however, there were no significant differences between both groups. INTERPRETATION: Although, the data did not show that radiological reduction criteria have a statistically significant effect on active functional outcome after a mean follow up time of 5.7 years, tendencies for a better outcome of patients that met the criteria could be seen. It also must be taken into consideration that results are limited by case number and allocation ratio, which made a sub-analysis of the separate reduction criteria unfeasible.

[Motion analysis in lower limb exoprosthetics-possibilities and limitations]. / Die Bewegungsanalyse in der Exoprothetik der unteren Extremität ­ Möglichkeiten und Grenzen.

BACKGROUND: Gait analysis is of high relevance in prosthetics as it is an essential part of the fitting process. The documentation of movement by means of videos and instrumented methods is becoming increasingly important in prosthetics as benefits of a complex prosthesis can best be shown by structured observation. PROCEDURE: A movement analysis should always be preceded by an anamnesis and clinical examination in order to detect functional limitations of the examined person and thus to establish correlations to gait deviations. Additionally, the orthopaedic aid should be evaluated as well. In addition to walking on level ground, walking on everyday obstacles such as stairs and ramps is also of interest when observing people using prosthetic limbs. Functional tests can be used to determine the functional status more comprehensively. An instrumental-3D gait analysis is indicated for specific questions, especially regarding kinetic parameters.

Tolerable degree of muscle sacrifice when harvesting a vastus lateralis or myocutaneous anterolateral thigh flap.

The myocutaneous anterolateral thigh (ALT) and vastus lateralis (VL) flaps include a large muscle mass and a sufficient vascular pedicle, and they have been used for decades to reconstruct traumatic and acquired defects of the head and neck and extremities. In spite of these benefits, musculoskeletal dysfunction was reported in nearly 1 out of 20 patients at follow-up. It is unclear whether the recently proposed muscle-sparing flap-raising approach could preserve VL muscle function and whether patients at increased risk could benefit from such an approach. Therefore, we performed a predictive dynamic gait simulation based on a biological motion model with gradual weakening of the VL during a self-selected and fast walking speed to determine the compensable degree of VL muscle reduction. Muscle force, joint angle, and joint moment were measured. Our study showed that VL muscle reduction could be compensated up to a certain degree, which could explain the observed incidence of musculoskeletal dysfunction. In elderly or fragile patients, the VL muscle should not be reduced by 50% or more, which could be achieved by muscle-sparing flap-raising of the superficial partition only. In young or athletic patients, a VL muscle reduction of 10%, which corresponds to a muscle cuff, has no relevant effect. Yet, a reduction of more than 30% leads to relevant weakening of the quadriceps. Therefore, in this patient population with the need for a large portion of muscle, alternative flaps should be considered. This study can serve as the first basis for further investigations of human locomotion after flap-raising.

Biomechanical comparison of a 3D-printed prosthetic foot with conventional feet in people with transtibial amputation: A prospective cohort study.

INTRODUCTION: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. METHODS: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. RESULTS: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. CONCLUSION: In principle, 3D-printed feet have advantages over conventional "off the shelf" feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.

Effect of different walking speeds on joint and muscle force estimation using AnyBody and OpenSim.

BACKGROUND: To be able to use muscluloskeletal models in clinical settings, it is important to understand the effect of walking speed on joint and muscle force estimations in different generic musculoskeletal models. RESEARCH QUESTION: The aim of the current study is to compare estimated joint and muscle forces as a function of walking speed between two standard approaches offered in two different modelling environments (AnyBody and OpenSim). METHODS: Experimental data of 10 healthy participants were recorded at three different walking speeds (self-selected, 25 % slower, 25 % faster) using a ten-camera motion capture system together with four force plates embedded into a ten-meter walkway. Joint compression forces and muscle forces were calculated with a generic model in AnyBody and OpenSim. Trend analyses, mean absolute error (MAE) and correlation coefficients were used to compare joint compression forces and muscle forces between the two approaches. A one-way and two-way ANOVA with repeated measures were used to compare MAE and trend analysis changes, respectively (α = 0.05, Bonferroni corrected post-hoc tests). RESULTS: Trend analyses showed the same speed effect for AnyBody and OpenSim. MAEs increased significantly from slow to fast walking for knee joint compression forces, biceps femoris long head, gluteus maximus, gluteus medius and vastus intermedius. Lower correlation coefficients during slower walking were found for quadriceps muscles, gluteus maximus and biceps femoris compared to normal and faster walking. SIGNIFICANCE: Lower correlation coefficients during slower walking are assumed to be due to a higher amount of solutions solving the muscle recruitment in musculoskeletal models. This indicates that decreasing walking speed is more prone to speed dependent differences regarding variability, while the absolute error increased with increasing walking speed. To conclude, different modelling environments can react differently to changes in walking speed, but overall results are promising regarding the generalization across different generic musculoskeletal models.

Automated detection and explainability of pathological gait patterns using a one-class support vector machine trained on inertial measurement unit based gait data.

BACKGROUND: Machine learning approaches for the classification of pathological gait based on kinematic data, e.g. derived from inertial sensors, are commonly used in terms of a multi-class classification problem. However, there is a lack of research regarding one-class classifiers that are independent of certain pathologies. Therefore, it was the aim of this work to design a one-class classifier based on healthy norm-data that provides not only a prediction probability but rather an explanation of the classification decision, increasing the acceptance of this machine learning approach. METHODS: The inertial sensor based gait kinematics of 25 healthy subjects was employed to train a one-class support vector machine. 25 healthy subjects, 20 patients after total hip arthroplasty and one transfemoral amputee served to validate the classifier. Prediction probabilities and feature importance scores were estimated for each subject. FINDINGS: The support vector machine predicted 100% of the patients as outliers from the healthy group. Three healthy subjects were predicted as outliers. The feature importance calculation revealed the hip in the sagittal plane as most relevant feature concerning the group after total hip arthroplasty. For the misclassified healthy subject with the lowest probability score the knee flexion and the pelvis obliquity were identified. INTERPRETATION: The support vector machine seems a useful tool to identify outliers from a healthy norm-group. The feature importance examination proved to provide valuable information on the musculoskeletal status of the subjects. In this combination, the present approach could be employed in various disciplines to identify abnormal gait and suggest subsequent training.

A Systematic Review of the Associations Between Inverse Dynamics and Musculoskeletal Modeling to Investigate Joint Loading in a Clinical Environment.

The assessment of knee or hip joint loading by external joint moments is mainly used to draw conclusions on clinical decision making. However, the correlation between internal and external loads has not been systematically analyzed. This systematic review aims, therefore, to clarify the relationship between external and internal joint loading measures during gait. A systematic database search was performed to identify appropriate studies for inclusion. In total, 4,554 articles were identified, while 17 articles were finally included in data extraction. External joint loading parameters were calculated using the inverse dynamics approach and internal joint loading parameters by musculoskeletal modeling or instrumented prosthesis. It was found that the medial and total knee joint contact forces as well as hip joint contact forces in the first half of stance can be well predicted using external joint moments in the frontal plane, which is further improved by including the sagittal joint moment. Worse correlations were found for the peak in the second half of stance as well as for internal lateral knee joint contact forces. The estimation of external joint moments is useful for a general statement about the peak in the first half of stance or for the maximal loading. Nevertheless, when investigating diseases as valgus malalignment, the estimation of lateral knee joint contact forces is necessary for clinical decision making because external joint moments could not predict the lateral knee joint loading sufficient enough. Dependent on the clinical question, either estimating the external joint moments by inverse dynamics or internal joint contact forces by musculoskeletal modeling should be used.

Movement Analysis in Orthopedics and Trauma Surgery - Measurement Systems and Clinical Applications. / Bewegungsanalyse in der Orthopädie und Unfallchirurgie ­ Messsysteme und deren klinische Anwendung.

BACKGROUND: Technical development lead to an enhancement of clinical movement analysis in the last few decades and expanded its research and clinical applications. Since the mid 20th century, human movement analysis has made its way into clinical practice, e.g. in treating poliomyelitis and infantile cerebral palsy. Today, it has a wide range of applications in various clinical areas. The aim of this narrative review is to illustrate the variety of camera-based systems for human movement analysis and their clinical applications, specifically in the field of orthopaedics and trauma surgery (O/U). Benefits and limitations of each system are shown. Future development and necessary improvements are discussed. MATERIAL AND METHODS: A selective literature review was undertaken with the databases PubMed and Google Scholar using keywords related to clinical human movement analysis in the field of orthopaedics and trauma surgery. Furthermore standard book references were included. RESULTS: Common video camera systems (VS) are used for basic visual movement analysis. Instrumented movement analysis systems include marker-based systems (MBS), markerless optical systems (MLS) and rasterstereographic analysis systems (VRS). VS, MBS and MLS have clinical use for dynamic examination of patients with various disorders in movement and gait. Among such are e.g. neuro-orthopaedic disorders, muscular insufficiencies, degenerative and post-trauma deficiencies with e.g. resultant pathologic leg axis. Besides the measurement of kinematic data by MBS and MLS, the combination with kinetic measurements to detect abnormal loading patterns as well as the combination with electromyography (EMG) to detect abnormal muscle function is a great advantage. Validity and reliability of kinematic measurements depend on the camera systems (MBS, MLS), the applied marker models, the joints of interest and the observed movement plane. Movements in the sagittal plane of the hip and knee joint, pelvic rotation and tilt as well as hip abduction are generally measured with high reliability. In the frontal and transverse planes of the knee and ankle joint substantial angular variabilities were noted due to the small range of motion of the joints in these planes. Soft tissue artefacts and marker placement are the biggest sources of errors. So far MLS did not improve these limitations. MBS are most accurate and remain the gold-standard in clinical and scientific movement analysis. VRS is used clinically for static 3D-analysis of the trunk posture and spine deformities. Current systems allow the dynamic measurement and visualisation of trunk and spine movement in 3D during gait and running. Planar x-ray-imaging (Cobb's angle) and to some extent cross sectional imaging with CT-scan or MRI are commonly used for the evaluation of patients with spinal deformities. VRS offers functional 3D data of trunk and spine deformities without radiation exposure, thus allowing safer clinical monitoring of the mainly infantile and adolescent patients. The accuracy, validity and reliability of measurements of different VRS-systems for the clinical use has been proven by several studies. CONCLUSION: The instrumented movement analysis is an additional tool that aids clinical practitioners of O/U in the dynamic assessment of pathologic movement and loading patterns. In conjunction with common radiologic imaging it aids in the planning of type and extent of corrective surgical interventions. In the field of orthopaedics and trauma surgery movement analysis can help as an additional diagnostic tool to develop therapeutic strategies and evaluate clinical outcomes.

Donor site morbidity of vascularized bone grafts from the medial femoral condyle for osseous revascularization.

BACKGROUND: Vascularized bone grafts from the medial femoral condyle (MFC) are used to gain surgical revascularization of osseous defects. To date objective data regarding the donor site morbidity are limited. This study aims to evaluate the donor site associated outcome after MFC flap harvest. PATIENTS AND METHODS: From 2008 to 2016, 22 patients who underwent MFC bone flap harvest for osseous revascularization of 9 talus, 8 scaphoids, 2 metacarpals, 1 phalanx, 1 pilon tibiale, and 1 distal femur were included. Outcome analysis was performed for the whole cohort as well as for two subgroups (recipient site upper [group A] and lower extremity [group B]) by the lower extremity functional scale (LEFS), the OAK-score of the Swiss Orthopedic Society and the visual analog scale (VAS). Additionally, a 3D gait analysis was performed for four patients. RESULTS: The mean flap size was 1 × 1 × 3 cm. No flap loss was observed. One minor surgical revision was performed due to donor site hematoma. Mean follow-up was 35.8 (12-98) months. Mean LEFS-score was 74.9 ± 9.5 (A: 74.3 ± 7.9; B: 75.6 ± 11.2, p > .05) and OAK-score was 92.8 ± 9.4 (A: 93.2 ± 5.8; B: 92.4 ± 12.3, p > .05). At follow-up examination, pain at rest was stated with 0.1 ± 0.2 (A: 0.1 ± 0.3; B 0 ± 0, p > .05) and with activity 0.6 ± 1.4 (A: 1.2 ± 1.8; B: 0 ± 0, p > .05) on VAS. The 3-D gait analysis showed normative walking patterns. CONCLUSION: After MFC flap harvest knee function and gait pattern were almost unimpaired. Donor site morbidity can be considered as being of minor concern in the decision-making for this microvascular procedure.

Muscle force estimation in clinical gait analysis using AnyBody and OpenSim.

A variety of musculoskeletal models are applied in different modelling environments for estimating muscle forces during gait. Influence of different modelling assumptions and approaches on model outputs are still not fully understood, while direct comparisons of standard approaches have been rarely undertaken. This study seeks to compare joint kinematics, joint kinetics and estimated muscle forces of two standard approaches offered in two different modelling environments (AnyBody, OpenSim). It is hypothesised that distinctive differences exist for individual muscles, while summing up synergists show general agreement. Experimental data of 10 healthy participants (28 ±â€¯5 years, 1.72 ±â€¯0.08 m, 69 ±â€¯12 kg) was used for a standard static optimisation muscle force estimation routine in AnyBody and OpenSim while using two gait-specific musculoskeletal models. Statistical parameter mapping paired t-test was used to compare joint angle, moment and muscle force waveforms in Matlab. Results showed differences especially in sagittal ankle and hip angles as well as sagittal knee moments. Differences were also found for some of the muscles, especially of the triceps surae group and the biceps femoris short head, which occur as a result of different anthropometric and anatomical definitions (mass and inertia of segments, muscle properties) and scaling procedures (static vs. dynamic). Understanding these differences and their cause is crucial to operate such modelling environments in a clinical setting. Future research should focus on alternatives to classical generic musculoskeletal models (e.g. implementation of functional calibration tasks), while using experimental data reflecting normal and pathological gait to gain a better understanding of variations and divergent behaviour between approaches.

Estimation of muscle activation during different walking speeds with two mathematical approaches compared to surface EMG.

BACKGROUND: Muscle force estimation could improve clinical gait analysis by enhancing insight into causes of impairments and informing targeted treatments. However, it is not currently standard practice to use muscle force models to augment clinical gait analysis, partly, because robust validations of estimated muscle activations, underpinning force modelling processes, against recorded electromyography (EMG) are lacking. RESEARCH QUESTION: Therefore, in order to facilitate future clinical use, this study sought to validate estimated lower limb muscle activation using two mathematical models (static optimisation SO, computed muscle control CMC) against recorded muscle activations of ten healthy participants. METHODS: Participants walked at five speeds. Visual agreement in activation onset and offset as well as linear correlation (r) and mean absolute error (MAE) between models and EMG were evaluated. RESULTS: MAE between measured and recorded activations were variable across speeds (SO vs EMG 15-68%, CMC vs EMG 13-69%). Slower speeds resulted in smaller deviations (mean MAE < 30%) than faster speeds. Correlation was high (r > 0.5) for only 11/40 (CMC) and 6/40 (SO) conditions (muscles X speeds) compared to EMG. SIGNIFICANCE: Modelling approaches do not yet show sufficient consistency of agreement between estimated and recorded muscle activation to support recommending immediate clinical adoption of muscle force modelling. This may be because assumptions underlying muscle activation estimations (e.g. muscles' anatomy and maximum voluntary contraction) are not yet sufficiently individualizable. Future research needs to find timely and cost efficient ways to scale musculoskeletal models for better individualisation to facilitate future clinical implementation.

A systematic review of approaches to modelling lower limb muscle forces during gait: Applicability to clinical gait analyses.

Computational methods to estimate muscle forces during walking are becoming more common in biomechanical research but not yet in clinical gait analysis. This systematic review aims to identify the current state-of-the-art, examine the differences between approaches, and consider applicability of the current approaches in clinical gait analysis. A systematic database search identified studies including estimated muscle force profiles of the lower limb during healthy walking. These were rated for quality and the muscle force profiles digitised for comparison. From 13.449 identified studies, 22 were finally included which used four modelling approaches: static optimisation, enhanced static optimisation, forward dynamics and EMG-driven. These used a range of different musculoskeletal models, muscle-tendon characteristics and cost functions. There is visually broad agreement between and within approaches about when muscles are active throughout the gait cycle. There remain, considerable differences (CV 7%-151%, range of timing of peak forces in gait cycle 1%-31%) in patterns and magnitudes of force between and within modelling approaches. The main source of this variability is not clear. Different musculoskeletal models, experimental protocols, and modelling approaches will clearly have an effect as will the variability of joint kinetics between healthy individuals. Limited validation of modelling approaches, particularly at the level of individual participants, makes it difficult to conclude if any of the approaches give consistently better estimates than others. While muscle force modelling has clear potential to enhance clinical gait analyses future research is needed to improve validation, accuracy and feasibility of implementation in clinical practice.

Estimated landmark calibration of biomechanical models for inverse kinematics.

Inverse kinematics is emerging as the optimal method in movement analysis to fit a multi-segment biomechanical model to experimental marker positions. A key part of this process is calibrating the model to the dimensions of the individual being analysed which requires scaling of the model, pose estimation and localisation of tracking markers within the relevant segment coordinate systems. The aim of this study is to propose a generic technique for this process and test a specific application to the OpenSim model Gait2392. Kinematic data from 10 healthy adult participants were captured in static position and normal walking. Results showed good average static and dynamic fitting errors between virtual and experimental markers of 0.8 cm and 0.9 cm, respectively. Highest fitting errors were found on the epicondyle (static), feet (static, dynamic) and on the thigh (dynamic). These result from inconsistencies between the model geometry and degrees of freedom and the anatomy and movement pattern of the individual participants. A particular limitation is in estimating anatomical landmarks from the bone meshes supplied with Gait2392 which do not conform with the bone morphology of the participants studied. Soft tissue artefact will also affect fitting the model to walking trials.

The influence of standards and clinical guidelines on prosthetic and orthotic service quality: a scoping review.

OBJECTIVES: Standards and guidelines are an integral part of prosthetic and orthotic service delivery in the developed world underpinned by an assumption that they lead to improved services. Implementing them has a cost, however, and that cost needs to be justified, particularly in resource-limited environments. This scoping review thus asks the question, "What is the evidence of the impact of standards and guidelines on service delivery outcomes in prosthetics and orthotics?" MATERIALS AND METHODS: A structured search of three electronic databases (Medline, Scopus and Web of Science) followed by manual searching of title, abstract and full text, yielded 29 articles. RESULTS: Four categories of papers were identified: Descriptions and Commentaries (17 papers), Guideline Development (7), Guideline Testing (2) and Standards implementation (3). No articles were explicitly designed to assess the impact of standards and guidelines on service delivery outcomes in prosthetics and orthotics. DISCUSSION AND CONCLUSION: Studies tended to be commentaries on or descriptions of guideline development, testing or implementation of standards. The literature is not sufficiently well developed to warrant the cost and effort of a systematic review. Future primary research should seek to demonstrate whether and how guidelines and standards improve the outcomes for people that require prostheses, orthoses and other assistive devices. Implications for Rehabilitation International Standards and Clinical Guidelines are now an integral part of clinical service provision in prosthetics and orthotics in the developed world. Complying with standards and guidelines has a cost and, particularly in resource-limited environments, it should be possible to justify this in terms of the resulting benefits. This scoping review concludes that there have been no previous studies designed to directly quantify the effects of implementing standards and guidelines on service delivery.

The influence of staff training and education on prosthetic and orthotic service quality: A scoping review.

BACKGROUND: Education and training in prosthetics and orthotics typically comply with International Society for Prosthetics and Orthotics standards based on three categories of prosthetic and orthotic professionals. OBJECTIVE: This scoping study sought to describe the evidence base available to answer the question, How are prosthetic and orthotic services influenced by the training of staff providing them? STUDY DESIGN: Scoping review. METHODS: A structured search of the peer-reviewed literature catalogued in major electronic databases yielded 3039 papers. Following review of title and abstract, 93 articles were considered relevant. Full-text review reduced this number to 25. RESULTS: Only two articles were identified as providing direct evidence of the effects of training and education on service provision. While both suggested that there was an impact, it is difficult to see how the more specific conclusions of either could be generalised. The other 23 articles provide a useful background to a range of issues including the specification of competencies that training programmes should deliver (3 articles), descriptions of a range of training programmes and the effects of training and education on student knowledge and skills. CONCLUSION: Although it is considered axiomatic, the service quality is dependent on practitioner education and training. There is insufficient evidence to establish whether levels of training and education in prosthetics and orthotics have an effect on the quality of prosthetic and orthotic services. Clinical relevance There is very little evidence about the effects of training and education of prosthetists and orthotists on service quality. While this is a somewhat negative finding, we feel that it is important to bring this to the attention of the prosthetics and orthotics community.

Stair dimension affects knee kinematics and kinetics in patients with good outcome after TKA similarly as in healthy subjects.

Joint biomechanics during stair walking may contain important information on functional deficits in patients with orthopaedic conditions but depend on the stair dimension. The goal of this study was to compare knee kinematics and kinetics between patients with good outcome 2 years after total knee arthroplasty (TKA) and age-matched controls during stair ascent and descent at two different stair heights. Principal component analysis was used to detect differences in gait mechanics between 15 patients and 15 controls at different stair conditions. Linear mixed models showed differences in knee kinematic and kinetic patterns (in flexion/extension and abduction/adduction) between stair heights. The knee adduction angle was more affected by stair heights in stair ascending whereas knee adduction moment and knee power were more affected during stair descent. Some stair by height and subject effects were small but not significant. Overall, good outcome after TKA is reflected in close-to-normal knee biomechanics during stair walking. Specific stair configuration must be considered when comparing joint biomechanics between subject groups and studies. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1753-1761, 2016.