Long-term development of gait after multilevel surgery in children with cerebral palsy: a multicentre cohort study.

AIM: We investigated the long-term efficacy and safety of multilevel surgery (MLS) in ambulatory children with bilateral spastic cerebral palsy (CP). METHOD: Two hundred and thirty-one children were evaluated at short term (1.1y, SD 0.4) and long term (9.1y, SD 3.0) follow-up using clinical examination and gait analysis. MLS was investigated by studying changes in the Gait Profile Score (GPS) referenced to the minimally important clinical difference. RESULTS: Ambulatory children aged 10 years and 7 months (SD 2y 11mo) at MLS in Gross Motor Function Classification System levels I (19), II (144), and III (68) showed a decrease (improvement) in preoperative GPS from 16.3° (SD 4.8) to 11.3° (SD 3.2) at short-term follow-up, an improvement of 5°. At long-term follow-up, GPS was maintained at 11.4° (SD 3.1). Overall, 177 (76.6%) children maintained their improvement in GPS after 9 years. INTERPRETATION: Multilevel surgery is a safe and effective surgical intervention, which leads to a significant improvement in gait kinematics in children with bilateral spastic CP. This study improves our understanding of MLS in the long term and will help to inform families and children when planning for MLS. WHAT THIS PAPER ADDS: Largest study of multilevel surgery (MLS) for children with bilateral spastic cerebral palsy, with longest follow-up. MLS resulted in significant long-term improvements in gait function. Minor adverse events were common, while events requiring intervention were uncommon (4% of children). Thirty-nine per cent of children required additional surgery during follow-up. 'Single-event multilevel surgery' was changed to the more realistic term 'multilevel surgery'.

Rotator cuff contact pressures at the tendon-implant interface after anatomic total shoulder arthroplasty using a metal-backed glenoid component.

BACKGROUND: Rotator cuff tears following anatomic total shoulder arthroplasty increase with duration of follow-up. This study aimed to evaluate contact pressure between the rotator cuff tendons and prosthesis after anatomic total shoulder arthroplasty and compare these with the tendon-contact pressures in the native shoulder. METHODS: Eight entire upper extremities were mounted onto a testing apparatus, and simulated muscle loading was applied to each rotator cuff tendon with the shoulder positioned in abduction, internal rotation, and external rotation. Pressure-sensitive film placed between each tendon and bone was used to measure the resultant tendon contact pressures. Experiments were repeated after anatomic total shoulder arthroplasty using standardized implant sizes, and pressure-sensitive film was used to evaluate tendon-prosthesis contact pressure. RESULTS: Both joint angle and shoulder joint replacement surgery had significant effects on the maximum contact pressure measured between the humeral head and all rotator cuff tendons (P < .05) except the teres minor. The supraspinatus demonstrated a significantly larger peak tendon contact pressure after surgery at 45° of abduction relative to that in the native shoulder (mean difference, 0.2 MPa; P = .031), while the subscapularis had a significantly larger maximum contact pressure at 10° of abduction (mean difference, 0.45 MPa; P = .032) and 90° of abduction (mean difference, 0.80 MPa; P = .008) postoperatively. CONCLUSION: Anatomic total shoulder arthroplasty results in significantly larger tendon contact pressures relative to those in the native shoulder. High tendon contact pressures may ultimately predispose rotator cuff tendons to postoperative wear-induced damage and tearing.

Three-dimensional measurement of femoral neck anteversion and neck shaft angle.

We present a three-dimensional measurement technique for femoral neck anteversion and neck shaft angles which do not require alignment of the femoral and scanner axes. Two assessors performed the measurements on 11 patients (22 femurs). Repeatability between assessors was 2.7 degrees for femoral neck anteversion and 4.8 degrees for neck shaft angle. Measurements compared with an alternative single slice method were different by 2 degrees (3 degrees) in average. The method was repeatable and appropriate for clinical practice.

Kinematic upper limb analysis outperforms electromyography at grading the severity of dystonia in children with cerebral palsy.

BACKGROUND: Severity of dyskinesia in children with cerebral palsy is often assessed using observation-based clinical tools. Instrumented methods to objectively measure dyskinesia have been proposed to improve assessment accuracy and reliability. Here, we investigated the technique and movement features that were most suitable to objectively measure the severity of dystonia in children with cerebral palsy. METHODS: A prospective observational study was conducted with 12 participants with cerebral palsy with a predominant motor type of dyskinesia, spasticity, or mixed dyskinesia/spasticity who had upper limb involvement (mean age: 12.6 years, range: 6.7-18.2 years). Kinematic and electromyography data were collected bilaterally during three upper limb tasks. Spearman rank correlations of kinematic or electromyography features were calculated against dystonia severity, quantified by the Dyskinesia Impairment Scale. FINDINGS: Kinematic features were more influential compared to electromyography features at grading the severity of dystonia in children with cerebral palsy. Kinematic measures quantifying jerkiness of volitional movement during an upper limb task with a reaching component performed best (|rs| = 0.78-0.9, p < 0.001). INTERPRETATION: This study provides guidance on the types of data, features of movement, and activity protocols that instrumented methods should focus on when objectively measuring the severity of dystonia in children with cerebral palsy.

Biomechanical gait parameters change with increasing virtual height in a child with spastic cerebral palsy: A case report.

Virtual height exposure coupled with motion capture is feasible to elicit changes in spatiotemporal, kinematic, and kinetic gait parameters in a child with cerebral palsy and should be considered when investigating gait in real-world-scenarios.

Current practices in clinical gait analysis in Europe: A comprehensive survey-based study from the European society for movement analysis in adults and children (ESMAC) standard initiative.

BACKGROUND: Clinical gait analysis (CGA) is a systematic approach to comprehensively evaluate gait patterns, quantify impairments, plan targeted interventions, and evaluate the impact of interventions. However, international standards for CGA are currently lacking, resulting in various national initiatives. Standards are important to ensure safe and effective healthcare practices and to enable evidence-based clinical decision-making, facilitating interoperability, and reimbursement under national healthcare policies. Collaborative clinical and research work between European countries would benefit from common standards. RESEARCH OBJECTIVE: This study aimed to review the current laboratory practices for CGA in Europe. METHODS: A comprehensive survey was conducted by the European Society for Movement Analysis in Adults and Children (ESMAC), in close collaboration with the European national societies. The survey involved 97 gait laboratories across 16 countries. The survey assessed several aspects related to CGA, including equipment used, data collection, processing, and reporting methods. RESULTS: There was a consensus between laboratories concerning the data collected during CGA. The Conventional Gait Model (CGM) was the most used biomechanical model for calculating kinematics and kinetics. Respondents also reported the use of video recording, 3D motion capture systems, force plates, and surface electromyography. While there was a consensus on the reporting of CGA data, variations were reported in training, documentation, data preprocessing and equipment maintenance practices. SIGNIFICANCE: The findings of this study will serve as a foundation for the development of standardized guidelines for CGA in Europe.

Consequences of Virtual Reality Experience on Biomechanical Gait Parameters in Children with Cerebral Palsy: A Scoping Review.

Virtual reality (VR), coupled with motion tracking, can investigate walking in a controlled setting while applying various walking challenges. The purpose of this review was to summarize the evidence on consequences of VR on biomechanical gait parameters in children with cerebral palsy. MEDLINE, Embase and Web of Science were searched. Among 7.574 studies, screened by two independent reviewers, seven studies were included, analyzing treadmill (n = 6) or overground walking (n = 1) under VR. Most frequently reported were the spatiotemporal parameters walking speed, stride length, step width, stance phase, and the kinematic parameters range of knee flexion and peak ankle dorsiflexion. However, methodological approaches and reporting of the results were inconsistent among studies. This review reveals that VR can complement information gained from clinical gait analysis. However, this is still an emerging field of research and there is limited knowledge on the effect of VR on gait parameters, notably during overground walking.

Improved Gait and Radiological Measurements After injection of Botulinum Toxin Into Peroneus Longus in Young Children With USCP and Equinovalgus Gait.

BACKGROUND: Children with cerebral palsy develop foot deformities due to a combination of factors including muscle shortening, hypertonia, weakness, and cocontraction of muscles acting at the ankle joint resulting in an altered gait pattern. We hypothesized these factors affect the peroneus longus (PL) and tibialis anterior (TA) muscles couple in children who develop equinovalgus gait first followed by planovalgus foot deformities. Our aim was to evaluate the effects of abobotulinum toxin A injection to the PL muscle, in a cohort of children with unilateral spastic cerebral palsy and equinovalgus gait. METHODS: This was a prospective cohort study. The children were examined within 12 months before and after injection to their PL muscle. Twenty-five children of mean age 3.4 (S.D.: 1.1) years were recruited. RESULTS: We found significant improvement in foot radiology measures. Passive extensibility of the triceps surae did not change, whereas active dorsiflexion increased significantly. Nondimensional walking speed increased by 0.1 (95% confidence interval [CI], [0.07, 0.16]; P < 0.001), and the Edinburgh visual gait score improved by 2.8 (95% CI, [-4.06, -1.46]; P < 0.001). Electromyography showed increased recruitment for gastrocnemius medialis (GM) and TA but not for PL during the reference exercises (standing on tip toes for GM/PL, active dorsiflexion for TA) and decreased activation percentages for PL/GM and TA across sub-phases of gait. CONCLUSIONS: One key advantage of treating the PL muscle only might be to address foot deformities without interfering with the main plantar flexors that are instrumental to support body weight during gait.

Management of children with ambulatory cerebral palsy: an evidence-based review. Commentary by Hugh Williamson Gait Laboratory staff.

The evaluation of complex interventions, such as Single Event Multilevel Surgery (SEMLS) requires more than randomized controlled trials. Rehabilitation following SEMLS is prolonged and the outcomes of interest may not be apparent for 5 years or more after the surgery. We suggest long term, prospective cohort studies with objective outcome measures be recognized as of equal importance to randomized controlled trials. The evidence in support of instrumented gait analysis (IGA) is also reviewed. We suggest that clinical levels of evidence are not an appropriate method to evaluate a measurement tool. Specifically, IGA should be evaluated in terms of validity, reliability and cost effectiveness. We demonstrate that the use of IGA has improved medium and long term outcomes in ambulant children with cerebral palsy in a center where IGA has been used routinely both for planning SEMLS and for monitoring outcomes.

Torsional deformities and overuse injuries: what does the literature tell us.

Overuse injuries imply the occurrence of a repetitive or an increased load on a specific anatomical segment which is unable to recover from this redundant microtrauma, thus leading to an inflammatory process of tendons, physis, bursa, or bone. Even if the aetiology is controversial, the most accepted is the traumatic one. Limb malalignment has been cited as one of the major risk factors implicated in the development of overuse injuries. Many authors investigated correlations between anatomical deviations and overuse injuries, but results appear mainly inconclusive. Establishing a causal relationship between mechanical stimuli and symptoms will remain a challenge, but 3D motion analysis, musculoskeletal, and finite element modelling may help in clarifying which are the major risk factors for overuse injuries.

Reduced plantar-flexors extensibility but improved selective motor control associated with age in young children with unilateral cerebral palsy and equinovalgus gait.

BACKGROUND: Children with spastic cerebral palsy gradually lose muscle extensibility but the interplay between the muscular and neurological components of the condition is unclear especially in the pathophysiology of equinovalgus gait. AIM: This study aimed to quantify the muscular and neurological disorders in young children with unilateral cerebral palsy, and to investigate the role of the peroneus longus (PL) in equinovalgus gait. DESIGN, SETTING AND POPULATION: This was an observational study with prospective assessments of 31 children (median age: 2.9 years, range: 2-6) from outpatient clinic in a tertiary teaching hospital. METHODS: Clinical measures of plantar flexor extensibility (XV1), stretch response (XV3), and active ankle dorsiflexion angle (XA) were obtained as well as walking velocity and electromyography of tibialis anterior (TA), gastrocnemius medialis (GM) and PL during walking. RESULTS: We found reduced extensibility of the triceps surae on the paretic side (effect size r = 0.73, p < 0.001 for soleus and r = 0.68, p < 0.001 for gastrocnemius) and a correlation between reduced triceps surae extensibility and earlier stretch response (ρ = 0.5, p = 0.004). During the swing phase, there was major co-contraction between TA and GM/PL, and significantly larger activation of PL compared to GM (r = 0.46, p = 0.011). Both GM and PL activation decreased with age. CONCLUSIONS: Our results suggest gradual deterioration of the muscular disorder and a link between the muscular and neurological disorders, although plantar flexor co-contraction improved with age. The PL was more activated than the GM and may be considered an intervention target to treat equinovalgus gait.

Reliability and sources of variability of 3D kinematics and electromyography measurements to assess newly-acquired gait in toddlers with typical development and unilateral cerebral palsy.

The aim was to 1) determine intersession and intertrial reliability and 2) assess three sources of variability (intersubject, intersession and intertrial) of lower limb kinematic and electromyographic (EMG) variables during gait in toddlers with typical development (TD) and unilateral cerebral palsy (UCP) (age <3 years, independent walking experience ≤6 months). Gait kinematics and surface EMG were recorded in 30 toddlers (19 TD and 11 UCP), during two, 3D-motion capture sessions. Standard error of measurement (SEM) between trials (gait cycles) of the same session and between sessions was calculated to assess reliability. Standard deviations (SD) between subjects, sessions and trials were calculated to estimate sources of variability. Sixty-four percent of kinematic SEM-values were acceptable (2°-5°). Frontal plane measurements were most reliable (SEM 2°-4.6°). In toddlers with UCP, EMG variables were most reliable for affected side, distal muscles. Intrinsic (intertrial and intersubject) variability was high, reflecting both motor immaturity and the high variability of toddler gait patterns. In toddlers with UCP, variability was amplified by motor impairment and delayed motor development. 3D gait analysis and surface EMG are partially reliable tools to study individual gait patterns in toddlers in clinical practice and research, although some variables must be interpreted with caution.

The impact of symptomatic femoral neck anteversion and tibial torsion on gait, function and participation in children and adolescents.

BACKGROUND: Torsional deformities of the lower limbs in children and adolescents are a common cause of in-toeing gait and cause gait deviations. The purpose of this study was to examine the relationship of children and adolescents with suspected Idiopathic Torsional Deformities (ITD) and pain, gait function, activity and participation. METHODS: A retrospective review of all children and adolescents who attended our Centre over a 5-year period for evaluation of the effect of ITD. All children completed three-dimensional gait analysis (3DGA), standardized physical examination, medical imaging and the Pediatric Outcomes Data Collection Instrument (PODCI). Statistical analysis was completed using two sample t-tests, Pearson's Correlation and linear regression. RESULTS: Fifty children and adolescents, 40 females and 10 males with a mean age of 13.5 years were included. Children reported a high prevalence of pain(86%), had increased internal hip rotation(p = 0.002) and decreased external hip rotation(p < 0.001) on physical examination when compared to published normative data. Medical imaging showed a mean(SD) femoral neck anteversion (FNA) of 38°(13°) and external tibial torsion of 39°(12°). Mean(SD) PODCI score was 32(16), indicating these children are functioning below their typically developing peers. The 3DGA kinematics show deviations from typical data including hip rotation, foot progression, pelvic tilt, hip flexion and knee extension. Observed mild kinetic deviations were within typical limits. The relationship between FNA and gait parameters, FNA and PODCI and gait and PODCI were weak. SIGNIFICANCE: These children and adolescents have altered gait and experience pain leading to impaired function and diminished participation. Therefore, ITD is not purely a cosmetic issue.

A Decision Support System to Facilitate Identification of Musculoskeletal Impairments and Propose Recommendations Using Gait Analysis in Children With Cerebral Palsy.

The identification of musculoskeletal impairments from gait analysis in children with cerebral palsy is a complex task, as is formulating (surgical) recommendations. In this paper, we present how we built a decision support system based on gait kinematics, anthropometrics, and physical examination data. The decision support system was trained to learn the association between these data and the list of impairments and recommendations formulated historically by experienced clinicians. Our aim was 2-fold, train a computational model that would be representative of data-based clinical reasoning in our center, and support new or junior clinicians by providing pre-processed impairments and recommendations with the associated supportive evidence. We present some of the challenges we faced, such as the issues of dimensionality reduction for kinematic data, missing data imputations, class imbalance and choosing an appropriate model evaluation metric. Most models, i.e., one model for each impairments and recommendations, achieved a weighted Brier score lower than 0.20, and sensitivity and specificity greater than 0.70 and 0.80, respectively. The results of the models are accessible through a web-based application which displays the probability predictions as well as the (up to) 5 best predictors.

Can pedobarography predict the occurrence of heel rocker in children with lower limb spasticity?

BACKGROUND: Pedobarography software calculates the centre-of-pressure trajectory in relation to the foot to quantify foot contact patterns. This study presents two new pedobarography measures using the centre-of-pressure trajectory to assess heel rocker. METHODS: To validate these pedobarography measures against 3D gait analysis, emed®-x and Vicon Nexus gait analysis data were captured from 25 children aged 8-16 years (11 male) with unilateral (n = 18) and bilateral (n = 7) cerebral palsy or acquired brain injury. 3D gait analysis identified whether heel rocker was intact (n = 22 feet) or absent (n = 28 feet) based on centre-of-pressure at initial contact and the ankle kinematic curve between 0 and 2% of the gait cycle. Pedobarography measures calculated from the initial centre-of-pressure point were the distance to the heel (point of initial contact) and to the most posterior point of the trajectory (rollback), reported as a percentage of foot length. FINDINGS: The median point of initial contact in limbs with an intact heel rocker was 9% (range 7-12%) and median rollback was 0% (range 0-0.2%), whereas the median point of initial contact in limbs with an absent heel rocker was 58% (range 8-78%) and rollback was 18% (range 0-40%). Point of initial contact is the more accurate method for predicting heel rocker, with a threshold of 14% of foot length identifying the correct heel rocker status in 94% of cases. INTERPRETATION: Point of initial contact can assess heel rocker with high accuracy. Both point of initial contact and rollback provide sensitive information on foot strike pattern, enhancing the utility of pedobarography.

Determination of the optimal locations of surface-mounted markers on the tibial segment.

This study aims to determine optimal locations on the lower limbs for skin-mounted markers representing the tibial segment in three-dimensional (3D) gait analysis. It was predicted that markers located on the anterior tibial crest and malleoli would be least susceptible to soft tissue movement. Ten retro-reflective markers were attached to each tibial segment for 20 participants. Participants performed 10 walking trials and two different range-of-movement tasks (knee flexion/extension and ankle plantarflexion/dorsiflexion). The results showed a subset of four markers with inter-marker pair distances on the tibia have less than 1.6 mm variation (standard deviation (S.D.)) during walking. Minimal variation was also found in isolated ROM tasks, where marker pairs showed variability of less than 2.2 mm. Other marker locations, the femoral epicondyles and the tibial tuberosity varied up to 4 mm during walking and up to 11 mm during the isolated ROM tasks. The four marker locations that are optimal for defining the tibia are the proximal anterior tibial crest, the distal anterior tibial crest, the lateral malleolus and the medial malleolus.

Utilizing three dimensional clinical gait analysis to optimize mobility outcomes in incomplete spinal cord damage.

BACKGROUND: Three-dimensional gait analysis (3DGA) has not previously been considered by consensus panels of spinal cord experts for use in studies of patients with spinal cord damage (SCD), yet it is frequently used in other neurological populations, such as stroke and cerebral palsy. RESEARCH QUESTION: How does 3DGA impairment based reporting guide individualised clinical decision-making in people with incomplete SCD? METHODS: Retrospective open cohort case series recruited 48 adults with incomplete SCD (traumatic or non-traumatic spinal cord dysfunction) referred to the Clinical Gait Analysis Service (CGAS), Melbourne, Australia. Three-dimensional gait data were used to identify gait impairments by the multidisciplinary clinical team. Gait patterns were classified using the plantarflexor-knee extension couple index and the Gait Profile Score (GPS). The reason for referral and the recommendations made post-3DGA were collated in decision trees to extrapolate the potential value of 3DGA in decision making for targeted intervention in this population. RESULTS: Participants with SCD generally walked at a reduced gait speed. When grouped by neurological level, the tetraplegia group had a significantly lower GPS, but no specific gait patterns emerged. Participants were primarily referred to the CGAS to direct clinical intervention decisions. The most frequent recommendation following 3DGA was the prescription of an ankle foot orthosis and in some cases, the recommendation was incongruent with the referrer's proposed intervention. SIGNIFICANCE: 3DGA can provide specific guidance in management plans for gait of patients with incomplete SCD and may help to avoid inappropriate or unnecessary interventions. This sample of patients referred to the CGAS demonstrates its clinical utility in guiding clinicians in their decision making to target individualised intervention.

Muscle and Joint Function After Anatomic and Reverse Total Shoulder Arthroplasty Using a Modular Shoulder Prosthesis.

Changes in joint architecture and muscle loading resulting from total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA) are known to influence joint stability and prosthesis survivorship. This study aimed to measure changes in muscle moment arms, muscle lines of action, as well as muscle and joint loading following TSA and RSA using a metal-backed uncemented modular shoulder prosthesis. Eight cadaveric upper extremities were assessed using a customized testing rig. Abduction, flexion, and axial rotation muscle moment arms were quantified using the tendon-excursion method, and muscle line-of-force directions evaluated radiographically pre-operatively, and after TSA and revision RSA. Specimen-specific musculoskeletal models were used to estimate muscle and joint loading pre- and post-operatively. TSA lateralized the glenohumeral joint center by 4.3 ± 3.2 mm, resulting in small but significant increases in middle deltoid force (2.0%BW) and joint compression during flexion (2.1%BW) (p < 0.05). Revision RSA significantly increased the moment arms of the major abductors, flexors, adductors, and extensors, and reduced their peak forces (p < 0.05). The superior inclination of the deltoid significantly increased while the inferior inclination of the rotator cuff muscles decreased (p < 0.05). TSA using an uncemented metal-backed modular shoulder prosthesis effectively restores native joint function; however, lateralization of the glenoid component should be minimized intra-operatively to mitigate increased glenohumeral joint loading and polyethylene liner contact stresses. Revision RSA reduces muscle forces required during shoulder function but produces greater superior joint shear force and less joint compression. The findings may help to guide component selection and placement to mitigate joint instability after arthroplasty. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1988-2003, 2019.

Computation of hip rotation kinematics retrospectively using functional knee calibration during gait.

BACKGROUND: Hip rotation kinematics during gait is a key parameter to support clinical decision making, for example in children with lower limb torsional deformities. However, hip rotation kinematics is also one of the least repeatable parameter because it is difficult to locate the position of the medio-lateral axis of the femur. Functional knee calibration provides an alternative to locate the medio-lateral axis of the femur and may be performed retrospectively, using the movement of the knee joint during gait. Although not necessarily more anatomically accurate, functional calibration may lead to increased repeatability between sessions, which would be useful to compare gait analysis data from sessions pre- and post-treatment, or to reprocess data in large gait databases. METHODS: This study presents a workflow to perform knee functional calibration using knee kinematics during gait and update hip rotation kinematics accordingly. The workflow was applied to investigate the inter-subject, inter-session and inter-trial variance components of multiple calibration methods in a group a 10 typically developing children. RESULTS: Results indicated that one or two degrees of freedom functional calibration methods were more repeatable inter-session (SD: 1.8°) than conventional calibration using the knee alignment device (SD: 4.7°). However, simulated reduced range of movement at the knee during gait increased inter-session variance for the functional calibration algorithms. Functional calibration did not provide any improvement over the conventional calibration when knee range of movement was reduced and flexion greater than 20° during gait, i.e. 'crouch gait'. SIGNIFICANCE: The workflow presented allows the re-processing of gait analysis data using knee kinematics during gait only. The workflow may also be used to investigate functional axes of other joints, for example the ankle.