Publications by authors named "Kranzl A"

Background: The assessment of gait disorders in patients with neuromotor conditions, such as cerebral palsy (CP), has been a focus of clinical and research attention, with electromyography (EMG) offering a nuanced understanding of neurological and neuromuscular disorders. However, the interpretation of EMG data in the context of gait analysis remains challenging due to the complexity of neuromotor dynamics and variability in assessment methodologies.

Research Question: To which consensus can we get in a group of experts in the fields of neurological and neuromuscular disorders, biomechanics, and clinical gait analysis to establish standardized protocols and a common language for the measurement and analysis of EMG data in gait disorders, particularly in people living with CP?

Methods: A three-round Delphi process was conducted from February to September 2023 to gather opinions of 53 experts on the use of surface EMG data during gait in the context of CP.

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Clinical gait analysis involves objective, valid, and reliable techniques for assessing gait function and is crucial for assessing walking patterns and identifying gait abnormalities in various patient populations. By analyzing joint angles, muscle activity, and other biomechanical factors during walking, clinicians can diagnose gait disorders, plan interventions, and improve patient outcomes. The GAMMA association aims to provide recommendations to support the standardization and quality assurance for clinical-instrumented 3D motion analysis services within the German-speaking region in central Europe.

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Article Synopsis
  • Osteogenesis imperfecta (OI) is a genetic disorder linked to type I collagen mutations, leading to bone fragility and deformities, with limited research on upper extremity issues in OI patients.
  • A study assessed 14 patients aged 8 to 73, analyzing upper limb deformities through radiographic methods, clinical evaluations, and three-dimensional motion analysis, categorizing deformities as mild, moderate, or severe.
  • Findings revealed that severe deformities, especially radial head dislocation, negatively impacted range of motion (ROM) and functional outcomes measured by the qDASH scores, indicating a spectrum of daily life activity limitations varying by deformity severity.
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Introduction: Femoral deformities are highly prevalent in children with cerebral palsy (CP) and can have a severe impact on patients' gait abilities. While the mechanical stress regime within the distal femoral growth plate remains underexplored, understanding it is crucial given bone's adaptive response to mechanical stimuli. We quantified stresses at the distal femoral growth plate to deepen our understanding of the relationship between healthy and pathological gait patterns, internal loading, and femoral growth patterns.

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The progress in markerless technologies is providing clinicians with tools to shorten the time of assessment rapidly, but raises questions about the potential trade-off in accuracy compared to traditional marker-based systems. This study evaluated the OpenCap system against a traditional marker-based system-Vicon. Our focus was on its performance in capturing walking both toward and away from two iPhone cameras in the same setting, which allowed capturing the Timed Up and Go (TUG) test.

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Internal rotation contractures of the shoulder are common sequelae of conservatively treated obstetric brachial plexus palsy (OBPP) with incomplete spontaneous neurological recovery. Humerus derotation osteotomy has been suggested as a possible treatment option to improve arm positioning. However, consensus as to whether humerus derotation osteotomy can successfully restore limb function is missing.

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Background: This study investigated the most accurate method for estimating the hip joint center position in clinical 3D gait analysis for young individuals with high amounts of soft tissue. We compared position estimates of five regression-based and two functional methods to the hip joint center position obtained through 3D free-hand ultrasound.

Methods: For this purpose, the data of 14 overweight or obese individuals with a mean age of 13.

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  • Clinical gait analysis (CGA) is essential for assessing gait patterns and planning interventions, but there are currently no international standards, leading to inconsistencies in practices across different countries.
  • A survey conducted by the European Society for Movement Analysis in Adults and Children (ESMAC) evaluated 97 gait laboratories across 16 European countries, focusing on equipment and methods used in CGA.
  • Results showed a general agreement on data collection methods and the use of the Conventional Gait Model, but highlighted differences in training and documentation practices, paving the way for standardized guidelines in the future.
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Excessive loads at lower limb joints can lead to pain and degenerative diseases. Altering joint loads with muscle coordination retraining might help to treat or prevent clinical symptoms in a non-invasive way. Knowing how much muscle coordination retraining can reduce joint loads and which muscles have the biggest impact on joint loads is crucial for personalized gait retraining.

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Femoral deformities, e.g. increased or decreased femoral anteversion (AVA) and neck-shaft angle (NSA), can lead to pathological gait patterns, altered joint loads, and degenerative joint diseases.

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The correct estimation of gait events is essential for the interpretation and calculation of 3D gait analysis (3DGA) data. Depending on the severity of the underlying pathology and the availability of force plates, gait events can be set either manually by trained clinicians or detected by automated event detection algorithms. The downside of manually estimated events is the tedious and time-intensive work which leads to subjective assessments.

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Background: X-linked hypophosphatemia (OMIM 307800) is a rare bone disease caused by a phosphate-wasting condition with lifelong clinical consequences. Those affected suffer from bone pain, complex skeletal deformities, impaired mobility and a reduced quality of life. Early osteoarthritis and reduced range of motion of the lower limbs are known pathologies in XLH patients.

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Background: Gait deviations, lower limb pain and joint stiffness represent key symptoms in patients with X-linked hypophosphatemia (XLH, OMIM 307800), a rare disorder of mineral homeostasis. While the pathomechanism for rickets is well understood, the direct role of PHEX (Phosphate-regulating neutral endopeptidase) deficiency in non-rachitic features including complex deformities, skull and dental affections remains unclear. FGF23-inhibiting antibody treatment can normalize serum phosphate levels and to improve rickets in XLH patients.

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Background: An exact definition is lacking for the term "weight-bearing" or different standing modalities when implementing foot radiographs for children and adults; moreover, only few studies have investigated the relationship between radiographic and pedobarographic measurements.

Research Question: We hypothesized that the method of weight-bearing in single-leg and both-leg standing positions could influence the measurement results in radiographs and the distribution of foot pressure.

Methods: This prospective study evaluated 33 children (66 feet) with flexible flatfoot deformities scheduled for subtalar screw arthroereisis surgery.

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  • Biallelic truncating variants causing cilia dysfunction have been identified in infants with Joubert syndrome and orofaciodigital syndrome; this report focuses on three adult siblings with a specific genetic variant.
  • Clinical examinations revealed neurological issues, abnormal gait, mild skeletal dysplasia, and several ocular conditions, indicating novel symptoms associated with this ciliopathy in adults.
  • The study emphasizes the importance of thorough clinical and genetic evaluations in families with complex disorders, as many neurogenetic conditions were present, potentially complicating diagnosis.
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Background: X-linked hypophosphatemia (XLH) is a rare genetic disorder characterized by lower limb deformity, gait and joint problems, and pain. Hence, quality of life is substantially impaired. This study aimed to assess lower limb deformity, specific radiographic changes, and gait deviations among adolescents and adults with XLH.

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Background: The minimally invasive distal metatarsal metaphyseal osteotomy (DMMO) is a percutaneous operative technique with the aim to relieve the symptoms of metatarsalgia. To our knowledge, no previous research has analyzed both pre- and postoperative pedobarographic data including the changes in plantar pressure.

Methods: Thirty patients (31 feet) were operated on with a DMMO and included in a prospective study.

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  • 3D free-hand ultrasound (3DFUS) is being adopted in clinical gait analysis because it is efficient, cost-effective, and does not involve radiation exposure.
  • The study evaluated 3DFUS's reliability in locating key skeletal landmarks (anterior superior iliac spine and hip joint centers) using multiple methods in both lean and obese individuals.
  • Results showed that while traditional methods (manual marker placement and instrumented pointer technique) had higher reliability, 3DFUS performed reasonably well, especially in obese individuals, and demonstrated acceptable accuracy in segmenting bony surfaces.
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Aims: The aims of this study is to report the clinical and radiological outcomes after pre-, central-, and postaxial polydactyly resection in children from a tertiary referral centre.

Methods: All children who underwent resection of a supernumerary toe between 2001 and 2013 were prospectively enrolled and invited for a single re-assessment. Clinical parameters and several dedicated outcome scores (visual analogue scale (VAS), Paediatric Outcomes Data Collection Instrument (PODCI), Activities Scale for Kids (ASK), and American Orthopaedic Foot and Ankle Society Score (AOFAS)) were obtained, as were radiographs of the operated and non-operated feet along with pedobarographs.

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Background: Recently, the successor of the Conventional Gait Model, the CGM2 was introduced. Even though achievable reliability of gait kinematics is a well-assessed topic in gait analysis for several models, information about reliability in difficult study samples with high amount of subcutaneous fat is scarce and to date, not available for the CGM2. Therefore, this study evaluated the test-retest reliability of the CGM2 model for difficult data with high amount of soft tissue artifacts.

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The aim of this study was to develop a generic musculoskeletal model of a healthy 10-year-old child and examine the effects of geometric scaling on the calculated values of lower-limb muscle forces during gait. Subject-specific musculoskeletal models of five healthy children were developed from in vivo MRI data, and these models were subsequently used to create a generic juvenile (GJ) model. Calculations of lower-limb muscle forces for normal walking obtained from two scaled-generic versions of the juvenile model (SGJ1 and SGJ2) were evaluated against corresponding results derived from an MRI-based model of one subject (SSJ1).

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Background: X-linked hypophosphatemia (XLH) represents the most common genetic form of rickets featuring profound hypophosphatemia with associated skeletal and non-skeletal manifestations. Early onset gait disturbances contribute strongly to the burden of disease. However, no study has comprehensively characterized naturally occurring gait deviations in pediatric patients with XLH.

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Background: We aimed to evaluate the effect of tibialis anterior tendon transfer (TATT) on foot motion in children with clubfoot recurrence after initial Ponseti treatment.

Methods: Children with dynamic clubfoot recurrence after initial Ponseti treatment who underwent TATT between 2014 and 2017 were considered for inclusion. Exclusion criteria were neurological disease, split transfer of the tendon, additional bone or joint invasive surgery, and initial treatment abroad.

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The creation of a single-bone-forearm is a salvage procedure to stabilize the forearm. The purpose of this study was to investigate clinical outcomes and how these patients compensate for the lack of forearm rotation. We evaluated four patients (three children, one adult) who had undergone single-bone-forearm surgery.

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Background: Research highlights the detrimental effects of obesity on gait biomechanics and the accompanied risk of lower-extremity skeletal malalignments, increased joint stress, pain and discomfort. Individuals with obesity typically show increased knee valgus angles combined with an increased step width. Accompanying muscular dysfunctions impede their ability to compensate for these alterations, especially in the frontal plane.

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