The effect of a neck-specific exercise program on cervical kinesthesia for patients with chronic whiplash-associated disorders: a case-control study.

INTRODUCTION: Cervical kinesthesia is an important part of movement control and of great importance for daily function. Previous research on kinesthesia in whiplash-associated disorders (WAD) has focused on grades I-II. More research is needed on WAD grade III. The aim of this study was to investigate cervical kinesthesia in individuals with WAD grades II-III before and after a neck-specific exercise intervention and compare them to healthy controls. METHODS: A prospective, case-control study with a treatment arm (n = 30) and a healthy control arm (n = 30) was conducted in Sweden. The WAD group received a neck-specific exercise program for 12 weeks. The primary outcome to evaluate kinesthesia was neck movement control (the Fly test). Secondary outcomes were neck disability, dizziness and neck pain intensity before and after the Fly test. Outcomes were measured at baseline and post-treatment. The control arm underwent measurements at baseline except for the dizziness questionnaire. A linear mixed model was used to evaluate difference between groups (WAD and control) and over time, with difficulty level in the Fly test and gender as factors. RESULTS: Between-group analysis showed statistically significant differences in three out of five kinesthetic metrics (p = 0.002 to 0.008), but not for the WAD-group follow-up versus healthy control baseline measurements. Results showed significant improvements for the WAD-group over time for three out of five kinaesthesia metrics (p < 0.001 to 0.008) and for neck disability (p < 0.001) and pain (p = 0.005), but not for dizziness (p = 0.70). CONCLUSIONS: The exercise program shows promising results in improving kinesthesia and reducing neck pain and disability in the chronic WAD phase. Future research might benefit from focusing on adding kinesthetic exercises to the exercise protocol and evaluating its beneficial effects on dizziness or further improvement in kinesthesia. IMPACT STATEMENT: Kinesthesia can be improved in chronic WAD patients without the use of specific kinesthetic exercises. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03664934), first registration approved 11/09/2018.

Toward New Assessment of Knee Cartilage Degeneration.

OBJECTIVE: Assessment of human joint cartilage is a crucial tool to detect and diagnose pathological conditions. This exploratory study developed a workflow for 3D modeling of cartilage and bone based on multimodal imaging. New evaluation metrics were created and, a unique set of data was gathered from healthy controls and patients with clinically evaluated degeneration or trauma. DESIGN: We present a novel methodology to evaluate knee bone and cartilage based on features extracted from magnetic resonance imaging (MRI) and computed tomography (CT) data. We developed patient specific 3D models of the tibial, femoral, and patellar bones and cartilages. Forty-seven subjects with a history of degenerative disease, traumatic events, or no symptoms or trauma (control group) were recruited in this study. Ninety-six different measurements were extracted from each knee, 78 2D and 18 3D measurements. We compare the sensitivity of different metrics to classify the cartilage condition and evaluate degeneration. RESULTS: Selected features extracted show significant difference between the 3 groups. We created a cumulative index of bone properties that demonstrated the importance of bone condition to assess cartilage quality, obtaining the greatest sensitivity on femur within medial and femoropatellar compartments. We were able to classify degeneration with a maximum recall value of 95.9 where feature importance analysis showed a significant contribution of the 3D parameters. CONCLUSION: The present work demonstrates the potential for improving sensitivity in cartilage assessment. Indeed, current trends in cartilage research point toward improving treatments and therefore our contribution is a first step toward sensitive and personalized evaluation of cartilage condition.

Healthy Aging Within an Image: Using Muscle Radiodensitometry and Lifestyle Factors to Predict Diabetes and Hypertension.

The strong age dependency of many deleterious health outcomes likely reflects the cumulative effects from a variety of risk and protective factors that occur over one's life course. This notion has become increasingly explored in the etiology of chronic disease and associated comorbidities in aging. Our recent work has shown the robust classification of individuals at risk for cardiovascular pathophysiology using CT-based soft tissue radiodensity parameters obtained from nonlinear trimodal regression analysis (NTRA). Past and present lifestyle influences the incidence of comorbidities like hypertension (HTN), diabetes (DM) and cardiac diseases. 2,943 elderly subjects from the AGES-Reykjavik study were sorted into a three-level binary-tree structure defined by: 1) lifestyle factors (smoking and self-reported physical activity level), 2) comorbid HTN or DM, and 3) cardiac pathophysiology. NTRA parameters were extracted from mid-thigh CT cross-sections to quantify radiodensitometric changes in three tissue types: lean muscle, fat, and loose-connective tissue. Between-group differences were assessed at each binary-tree level, which were then used in tree-based machine learning (ML) models to classify subjects with DM or HTN. Classification scores for detecting HTN or DM based on lifestyle factors were excellent (AUCROC: 0.978 and 0.990, respectively). Finally, tissue importance analysis underlined the comparatively-high significance of connective tissue parameters in ML classification, while predictive models of DM onset from five-year longitudinal data gave a classification accuracy of 94.9%. Altogether, this work serves as an important milestone toward the construction of predictive tools for assessing the impact of lifestyle factors and healthy aging based on a single image.

Machine learning predictive system based upon radiodensitometric distributions from mid-thigh CT images.

The nonlinear trimodal regression analysis (NTRA) method based on radiodensitometric CT images distributions was developed for the quantitative characterization of soft tissue changes according to the lower extremity function of elderly subjects. In this regard, the NTRA method defines 11 subject-specific soft tissue parameters and has illustrated high sensitivity to changes in skeletal muscle form and function. The present work further explores the use of these 11 NTRA parameters in the construction of a machine learning (ML) system to predict body mass index and isometric leg strength using tree-based regression algorithms. Results obtained from these models demonstrate that when using an ML approach, these soft tissue features have a significant predictive value for these physiological parameters. These results further support the use of NTRA-based ML predictive assessment and support the future investigation of other physiological parameters and comorbidities.

Patient-specific mobility assessment to monitor recovery after total hip arthroplasty.

Total hip arthroplasty is a ubiquitously successful orthopedic surgical procedure, whose prevalence is rising worldwide. While many investigations focus on characterizing periprosthetic pathophysiology, the objective of our research is to develop and describe multi-metric assemblies as a first step toward creating a patient-specific mobility index that rehabilitators and orthopedic surgeons can utilize for prescribing their respective procedures. In total, 48 total hip arthroplasty patients (both cemented and uncemented) undergoing unilateral, primary surgery went through computed tomographic scans and gait analysis measurements both before and 1 year following their surgery. Altogether, the reported quantitative metrics include 11 spatial and temporal gait parameters, muscle density, and electromyography signals from the rectus femoris, vastus lateralis, and vastus medialis, and bone mineral density values from bioimage analysis around the implant stem. We found that measured parameters from a subgroup were sensitive to changes observed during patient recovery, implicating the predictive sensitivity of these patient conditions. Most post-operative gait parameters changed significantly, while electromyography data indicated few significant differences. Moreover, results from bioimage analyses indicate a general reduction of periprosthetic bone mineral density after 1 year, in association with increasing density of the quadriceps muscles. Furthermore, this work identifies which quantitative metrics undergo the greatest variation after total hip arthroplasty and demonstrates the clinical feasibility of a multimodal approach to mobility assessment that may ultimately support decision-making for post-surgical rehabilitation protocols.

Women with late whiplash syndrome have greatly reduced load-bearing of the cervical spine. In-vivo biomechanical, cross-sectional, lateral radiographic study.

BACKGROUND: No study has been conducted to ascertain whether the load-bearing capacity of the cervical spine is reduced in vivo in late whiplash syndrome (LWS). AIM: To compare the segmental cervical angular values across C0-C6, between two conditions: without versus with external axial load upon the head in three groups of women. DESIGN: A single-blind, age-Body Mass Index (BMI) matched, radiographic, cross-sectional study. SETTING: Radiographic Department at a University Hospital. POPULATION: One hundred eighty-two women, aged between 18-50 years were enrolled. METHODS: Participants were divided into 3 groups: a group with LWS (N.=62) and two control groups: a chronic insidious neck pain (IONP) group (N.=60) and an asymptomatic group (N.=60). Prior to and on the same day as the radiographic examination took place, BMI in kg/m2 was recorded and all participants answered the Neck Disability Index (NDI). The two symptomatic groups answered also three other pain and disability questionnaires. RESULTS: Analysis of variance (mixed-model ANOVA) for repeated measures was used for comparison. Significant differences between groups, and the two conditions tested was revealed, but only within the asymptomatic and the IONP groups (P<0.0001), but not within the LWS group (P=0.9433). Unexpectedly the women with LWS adopted a rigid horizontal translation strategy when external load was applied upon their head. The inter-rater and intra-rater segmental measurements were highly reliable. Women with LWS scored significantly higher on all questionnaires. CONCLUSIONS: The results of this study strongly indicate that the load-bearing capacity of the cervical spine is reduced in vivo in women with LWS. The study shows, for the first time, that the cervical spine in women with LWS predominately functions such as a rigid cylinder when loaded. CLINICAL REHABILITATION IMPACT: The study implies that the cervical column is extremely weak in the LWS and that the superficial neck muscles, which are designed to move the head-neck, must compensate and act as rigid stabilizers. This causes great joint reaction forces through the cervical spine and its injured inert structures maintaining the pain and disability, as the results of the questionnaires show.

Patient-specific bone mineral density distribution in the tibia of individuals with chronic spinal cord injury, derived from multi-slice peripheral Quantitative Computed Tomography (pQCT) - A cross-sectional study.

BACKGROUND: The high risk of fracture associated with chronic spinal cord injury (SCI) is attributed to extensive disuse-related bone loss in previously weight-bearing long bones. Changes in bone mineral density (BMD) after SCI have been documented extensively for the epiphyses of the tibia and femur, fracture-prone sites in this patient group. Less attention has been given to patterns of cortical bone loss in the diaphyses, but variability in BMD distributions throughout the long bones may contribute to some patients' increased susceptibility to shaft fractures in chronic SCI. AIM: A cross-sectional study was carried out to determine whether BMD distributions along the tibia differ between individuals with chronic SCI and healthy able-bodied (AB) controls, in both the trabecular and cortical bone compartments. The effects of time post-injury and gender on BMD distribution were also explored. METHODS: Individuals with chronic (≥6months post-injury) motor-complete SCI were recruited from the Queen Elizabeth National Spinal Injuries Unit (Glasgow, UK). AB control subjects were recruited to achieve similar age and gender profiles for the SCI and control groups. Multi-slice pQCT (XCT3000, Stratec) was performed along the length of the tibia (2mm thickness, 0.5mm voxel size), at 1% intervals in the epiphyses and 5% intervals in the diaphysis (34 slices in total). These were used to reconstruct full 3-D subject-specific models (Mimics, Materialise) of BMD distribution, by interpolating between slices. Subjects with chronic SCI were subdivided into 'early' (<4years post-injury) and 'established' SCI (≥4years post-injury). Subject-specific BMD distribution was described according to new parameters determined from the 3-D patient-specific models, quantifying descriptors of the trabecular and cortical BMD regions separately (volume, peak BMD, half-peak width, area under the curve). These were compared between sub-groups (using independent-samples t-tests or Mann-Whitney tests, significance level of 5%). RESULTS: 11 men (age range 17-59years old; mean 35.7±10.6) and 3 post-menopausal women (age range 56-58years old; mean 56.7±1.2years) with motor-complete SCI (ranging from 6months to 27years post-injury) were recruited; 6 men (age range 20-56years old; 33.0±12.7years) and 1 post-menopausal woman (56years) formed the AB control group. Overall, SCI resulted in lower BMD at both trabecular and cortical regions of the tibia. In men, longer time since injury resulted in greater BMD differences when compared to AB, throughout the tibia. For the post-menopausal women, differences in BMD between SCI and AB were greater in cortical bone than in trabecular bone. From the models, individual BMD distribution curves showed healthy double-peaks in AB subjects: one trabecular peak (around 200-300mg/cm3) and the other cortical (around 1000-1100mg/cm3). In most subjects with established SCI, trabecular peaks were exaggerated whilst the cortical peaks were barely discernible, with crucially some individuals already exhibiting a diminishing cortical BMD peak even <4years post-injury. CONCLUSIONS: These findings may have implications for determining the fracture susceptibility of the long bones in individual patients with SCI. Epiphyseal fractures associated with low trabecular BMD are well characterised, but our data show that some individuals with SCI may also be at higher risk of shaft fractures. The proposed BMD distribution description parameters, determined from patient-specific models, could be used to identify patients with a weakened diaphysis who may be susceptible to fractures of the tibial shaft, but this requires validation.

Quantitative Computed Tomography and Image Analysis for Advanced Muscle Assessment.

Medical imaging is of particular interest in the field of translational myology, as extant literature describes the utilization of a wide variety of techniques to non-invasively recapitulate and quantity various internal and external tissue morphologies. In the clinical context, medical imaging remains a vital tool for diagnostics and investigative assessment. This review outlines the results from several investigations on the use of computed tomography (CT) and image analysis techniques to assess muscle conditions and degenerative process due to aging or pathological conditions. Herein, we detail the acquisition of spiral CT images and the use of advanced image analysis tools to characterize muscles in 2D and 3D. Results from these studies recapitulate changes in tissue composition within muscles, as visualized by the association of tissue types to specified Hounsfield Unit (HU) values for fat, loose connective tissue or atrophic muscle, and normal muscle, including fascia and tendon. We show how results from these analyses can be presented as both average HU values and compositions with respect to total muscle volumes, demonstrating the reliability of these tools to monitor, assess and characterize muscle degeneration.

Tensile properties of the transverse carpal ligament and carpal tunnel complex.

BACKGROUND: A new sophisticated method that uses video analysis techniques together with a Maillon Rapide Delta to determine the tensile properties of the transverse carpal ligament-carpal tunnel complex has been developed. METHODS: Six embalmed cadaveric specimens amputated at the mid-forearm and aged (mean (SD)): 82 (6.29) years were tested. The six hands were from three males (four hands) and one female (two hands). Using trigonometry and geometry the elongation and strain of the transverse carpal ligament and carpal arch were calculated. The cross-sectional area of the transverse carpal ligament was determined. Tensile properties of the transverse carpal ligament-carpal tunnel complex and Load-Displacement data were also obtained. Descriptive statistics, one-way ANOVA together with a post-hoc analysis (Tukey) and t-tests were incorporated. FINDINGS: A transverse carpal ligament-carpal tunnel complex novel testing method has been developed. The results suggest that there were no significant differences between the original transverse carpal ligament width and transverse carpal ligament at peak elongation (P=0.108). There were significant differences between the original carpal arch width and carpal arch width at peak elongation (P=0.002). The transverse carpal ligament failed either at the mid-substance or at their bony attachments. At maximum deformation the peak load and maximum transverse carpal ligament displacements ranged from 285.74N to 1369.66N and 7.09mm to 18.55mm respectively. The transverse carpal ligament cross-sectional area mean (SD) was 27.21 (3.41)mm(2). INTERPRETATION: Using this method the results provide useful biomechanical information and data about the tensile properties of the transverse carpal ligament-carpal tunnel complex.

Prediction of risk of fracture in the tibia due to altered bone mineral density distribution resulting from disuse: a finite element study.

The disuse-related bone loss that results from immobilisation following injury shares characteristics with osteoporosis in post-menopausal women and the aged, with decreases in bone mineral density leading to weakening of the bone and increased risk of fracture. The aim of this study was to use the finite element method to: (i) calculate the mechanical response of the tibia under mechanical load and (ii) estimate of the risk of fracture; comparing between two groups, an able-bodied group and spinal cord injury patients group suffering from varying degrees of bone loss. The tibiae of eight male subjects with chronic spinal cord injury and those of four able-bodied age-matched controls were scanned using multi-slice peripheral quantitative computed tomography. Images were used to develop full three-dimensional models of the tibiae in Mimics (Materialise) and exported into Abaqus (Simulia) for calculation of stress distribution and fracture risk in response to specified loading conditions - compression, bending and torsion. The percentage of elements that exceeded a calculated value of the ultimate stress provided an estimate of the risk of fracture for each subject, which differed between spinal cord injury subjects and their controls. The differences in bone mineral density distribution along the tibia in different subjects resulted in different regions of the bone being at high risk of fracture under set loading conditions, illustrating the benefit of creating individual material distribution models. A predictive tool can be developed based on these models, to enable clinicians to estimate the amount of loading that can be safely allowed onto the skeletal frame of individual patients who suffer from extensive musculoskeletal degeneration (including spinal cord injury, multiple sclerosis and the ageing population). The ultimate aim is to reduce fracture occurrence in these vulnerable groups.

Finite Element Modelling of the Femur Bone of a Subject Suffering from Motor Neuron Lesion Subjected to Electrical Stimulation.

Bone loss and a decrease in bone mineral density is frequently seen in patients with motor neuron lesion due to lack of mechanical stimulation. This causes weakening of the bones and a greater risk of fracture. By using functional electrical stimulation it is possible to activate muscles in the body to produce the necessary muscle force to stimulate muscle growth and potentially decrease the rate of bone loss. A longitudinal study was carried out on a single patient undergoing electrical stimulation over a 6 year period. The patient underwent a CT scan each year and a full three dimensional finite element model for each year was created using Mimics (Materialise) and Abaqus (Simulia) to calculate the risk of fracture under physiologically relevant loading conditions. Using empirical formulas connecting the bone mineral density to the stiffness and ultimate tensile stress of the bone, each element was assigned a unique material property, based on its density. The risk of fracture was estimated by calculating the ratio between the predicted stress and the ultimate tensile stress, should it exceed unity, failure was assumed. The results showed that the number of elements that were predicted to be at risk of failure varied between years.

Finite element model creation and stability considerations of complex biological articulation: The human wrist joint.

The finite element method has been used with considerable success to simulate the behaviour of various joints such as the hip, knee and shoulder. It has had less impact on more complicated joints such as the wrist and the ankle. Previously published finite element studies on these multi-bone joints have needed to introduce un-physiological boundary conditions in order to establish numerical convergence of the model simulation. That is necessary since the stabilizing soft tissue mechanism of these joints is usually too elaborate in order to be fully included both anatomically and with regard to material properties. This paper looks at the methodology of creating a finite element model of such a joint focussing on the wrist and the effects additional constraining has on the solution of the model. The study shows that by investigating the effects each of the constraints, a better understanding on the nature of the stabilizing mechanisms of these joints can be achieved.