Global Research Trends on Gait Rehabilitation in Individuals With Spinal Cord Injury- A Bibliometric Analysis.

STUDY DESIGN: Bibliometric analysis. OBJECTIVE: The study aims to comprehensively assess the literature related to gait rehabilitation for individuals with spinal cord injury (SCI) to identify significant contributors, and to explore the collaborations and emerging themes in the field. METHODS: Original and review articles in English using relevant keywords were searched in the Clarivate Web of Science database. The data from the selected articles were imported into R software. Bibliometric indicators were assessed to determine author contributions, country affiliations, journal sources, and thematic trends. RESULTS: A total of 1313 relevant articles were identified. The USA, followed by Canada and Switzerland were the most prolific countries contributing to gait rehabilitation research in SCI. The most relevant journals were Spinal Cord, Archives of Physical Medicine and Rehabilitation, Journal of Spinal Cord Medicine, Journal of NeuroEngineering, and Journal of Neurotrauma. The highest contributions came from Northwestern University, the University of Miami, and the University of Alberta. The analysis revealed an increase in research interest in gait rehabilitation after 2000, with a focus on interdisciplinary approaches and emerging technologies like robotics, exoskeletons, and neuromodulation. CONCLUSION: The analysis demonstrates the importance of collaborative and interdisciplinary research in gait rehabilitation. The results indicate a shift in research focus from traditional methods to the integration of technology. The impact of publications from the USA and Europe is a notable finding. The study highlights the growth of articles related to technology-driven approaches and understanding neuroplasticity in gait rehabilitation.

An Assessment of the World's Contribution to Spine Trauma Care: A Bibliometric Analysis of Classifications and Surgical Management; An AO Spine Knowledge Forum Trauma Initiative.

STUDY DESIGN: Bibliometric analysis. OBJECTIVES: An analysis of the literature related to the assessment and management of spinal trauma was undertaken to allow the identification of top contributors, collaborations and research trends. METHODS: A search to identify original articles published in English between 2011 and 2020 was done using specific keywords in the Web of Science database. After screening, the top 300 most cited articles were analyzed using Biblioshiny R software. RESULTS: The highest number of contributions were from the Thomas Jefferson University, USA, University of Toronto and University of British Columbia, Canada. The top 3 most prolific authors were Vaccaro AR, Arabi B, and Oner FC. The USA and Canada were among the top contributing countries; Switzerland and Brazil had most multiple country co-authored articles. The most relevant journals were the European Spine Journal, Spine and Spine Journal. Three of the 5 most cited articles were about classification systems of fractures. The keyword analysis included clusters for different spinal regions, spinal cord injury, classification agreement and reliability studies, imaging related studies, surgical techniques and outcomes. CONCLUSIONS: The study identified the most impactful authors and affiliations, and determined the journals where most impactful research is published in the field. Study also compared the productivity and collaborations across countries. The study highlighted the impact of development of new classification systems, and identified research trends including instrumentation, fixation and decompression techniques, epidemiology and recovery after spinal trauma.

Electromyographic analysis of trunk and hip muscles during Yoga poses prescribed for treating chronic low back pain.

Yoga is effective for the management of chronic low back pain as it improves muscle strength and endurance. The objective of the current study was to assess trunk and hip muscle activation during Yoga poses usually prescribed for patients with chronic LBP. The study included 22 healthy Yoga trained subjects (mean age: 24.4 ± 2.6 years; 16 females, 6 males). The testing involved collecting surface electromyography data from Rectus Abdominis (RA) and Transverse Abdominis (TA), Gluteus Medius (GM), and Erector Spinae (ES) as subjects attained and held 16 different Yoga poses in standing, kneeling, supine, or prone positions in random order. The signal of each muscle was processed and normalized to its maximum voluntary isometric contraction (MVC). Statistical comparisons were made across selected poses and phases (attaining and holding) for each muscle using repeated-measures ANOVA. The data was also descriptively analyzed for sorting muscle activity. The activation of trunk flexors was significantly higher during boat pose (>50% MVC) followed by plank pose (∼30% MVC), activation of ES was significantly higher during reverse boat (41.7% ± 3.3 MVC) as compared to bow, snake, backward-sway, and warrior poses. The GM activation was significantly less in standing poses than during side-lying and Tiger poses (32-42% MVC). The cat-camel, kneeling camel, downward dog, backward-sway, swaying-palm tree, and warrior poses activated all tested muscles fairly (<20% MVC). The study helps the grading of Yoga positions according to the challenge imposed. The challenging poses may be used to develop graded rehabilitation programs to improve muscle strength/endurance.

Physiotherapeutic Interventions for Upper Cross Syndrome: A Systematic Review and Meta-Analysis.

Upper cross syndrome is a postural dysfunction that can cause a variety of upper-body musculoskeletal problems. Early detection and physiotherapy can help to prevent further complications. However, no systematic review has evaluated the effect of various physiotherapy intervention strategies to treat this syndrome. Therefore, this study aims to conduct a detailed methodological literature search of the most effective treatment strategies available for the correction of upper cross syndrome. Prospective human subject studies published in the English language that report the assessment and rehabilitation of upper cross syndrome were included. Clinical trials (randomized and non-randomized) were included when compared to a comparator, control group, and no treatment. The search was limited to human subjects and English-language articles. Outcome measures included craniovertebral angle, kyphotic angle, rounded shoulder, neck or shoulder pain, neck range of motion, electromyographic activity of neck or scapular muscles, and functional limitations. To evaluate the methodological quality of randomized controlled trials, the Cochrane collaboration tool was employed. For non-randomized studies, the Risk of Bias in Non-randomized Studies of Intervention was used. The Grading of Recommendations, Assessment, Development, and Evaluation system was used to rate the effectiveness of the evidence. A random-effect meta-analysis was performed for quantitative analysis to report significant differences based on calculated mean differences, with matching 95% confidence intervals (CIs) whenever possible. Out of the 34 potentially relevant articles, 18 were included. The postural variables including craniovertebral angle, kyphotic angle, and rounded shoulder showed a significant improvement with the physiotherapy group compared to the no-treatment group (standardized mean difference = -1.78; 95% CI = -2.68 to -0.87; p = 0.0001). Secondary outcomes such as pain and functional limitation showed a significant difference when advanced manual therapy techniques were used compared to conventional therapy (standardized mean difference = -0.71; 95% CI = -1.04 to -0.39; p< 0.0001; and standardized mean difference = -0.57; 95% CI = -1.00 to -0.14; p = 0.009, respectively). Exercise therapy was found to be beneficial in correcting postural alignment and movement patterns, while manual therapy was found to be similarly effective in pain reduction and functional improvement.

Reliability and Concurrent Validity of Smartphone Clinometer Application for Measuring Scapular Rotations in Subjects With and Without Shoulder Pain.

CONTEXT:   Clinical assessment of scapular motion is obscured by a lack of clinically accessible and feasible angular measurement tools. This study evaluates the reliability and validity of the smartphone "Clinometer" app in measuring scapular upward rotation (UR) and anteroposterior tilt. DESIGN: Psychometric analysis. METHODS: We recruited 57 participants-10 with and 47 without shoulder pain. Two physical therapists consecutively measured both scapular movements using the Clinometer app at the arm by the side (rest), 30°, 60°, 90°, and 120° of humeral elevation in the scapular plane; one therapist measured again after 2 days. For evaluating concurrent validity, we compared the Clinometer scores with those measured using an electromagnetic motion capture system in 10 healthy participants. Intraclass correlation coefficients (ICC) with standard error of measurement (SEM) and minimal detectable difference at 90% confidence intervals (MDD90) were calculated. Concurrent validity was evaluated using repeated-measures analysis of variance followed by post hoc testing with Tukey-Kramer test (P < .05). RESULTS: We observed good intrarater reliability (ICC: UR = .76-.85, tilt = .69-.9; SEM: 2.2°-3.5°; MDD90: ∼5°-8°) and moderate to good interrater reliability (ICC: UR = .66-.78, tilt = .66-.76; SEM: 3.6°-8°; MDD90: ∼9°-18°) for both rotations. The Clinometer scores for UR were comparable to electromagnetic motion capture system at all angles except 90° (difference ∼8°); for scapular tilt, the scores were comparable only at rest and 30° elevation. CONCLUSION: The Clinometer app is reliable and valid for measuring scapular UR throughout and for scapular tilt at lower humeral elevation angles. The MDD90 values for scapular rotations computed in this study can be helpful in rehabilitation planning and future research.

Ratio between 3D glenohumeral and scapulothoracic motions in individuals without shoulder pain.

This study determined the ratio between glenohumeral and three-dimensional scapular motion during arm elevation and lowering in 91 individuals without shoulder pain. Scapular kinematics were assessed using an electromagnetic tracking device. Individuals performed 3 repetitions of elevation and lowering of the arm in the sagittal plane. Two-way ANOVAs (interval: 30-60°, 60-90°, 90-120° x phase: elevation and lowering) and paired t-tests were used for data analysis. For scapular internal/external rotation, lesser scapular internal rotation contribution was found during the 60-90° interval as compared to the 90-60° interval. Lesser scapular external rotation was identified in the 60-30° interval of arm lowering. The ratio was greater during arm elevation (1.89) compared to lowering (1.74) across the entire motion arc. For scapular upward rotation, greater upward rotation contribution was observed during arm elevation at the 30-60° interval, and less scapular downward rotation contribution in the final range of arm lowering. For scapular tilt, lesser scapular posterior tilt contribution during arm elevation was observed compared to arm lowering. The ratios between glenohumeral elevation/lowering and each individual scapulothoracic motion showed either differences between intervals and/or between elevation and lowering during specific intervals in healthy individuals.

Errors in Measuring Glenohumeral Arthrokinematics With 2-Dimensional Fluoroscopy.

Two-dimensional fluoroscopic imaging allows measurement of small magnitude humeral head translations that are prone to errors due to optical distortion, out-of-plane imaging, repeated manual identification of landmarks, and magnification. This article presents results from in vivo and in vitro fluoroscopy-based experiments that measure the errors and variability in estimating the humeral head translated position in true scapular plane and axillary views. The errors were expressed as bias and accuracy. The variability with repeated digitization was calculated using the intraclass correlation coefficient (ICC) and the standard error of measurement. Optical distortion caused underestimation of linear distances. The accuracy was 0.11 and 0.43 mm for in vitro and in vivo experiments, respectively, for optical distortion. The intrarater reliability was excellent for both views (ICC = .94 and .93), and interrater reliability was excellent (ICC = .95) for true scapular view but moderate (ICC = .74) for axillary views. The standard error of measurement ranged from 0.27 to 0.58 mm. The accuracy for the humeral head position in 10° out of true scapular plane images ranged from 0.80 to 0.87 mm. The current study quantifies the magnitude of error. The results suggest that suitable measures could be incorporated to minimize errors and variability for the measurement of glenohumeral parameters.

Concurrent validity of inclinometer measures of scapular and clavicular positions in arm elevation.

OBJECTIVE: To assess concurrent validity, between and within-day reliability of scapular and clavicular digital inclinometer measures. DESIGN: Test-retest and concurrent validity. SETTING: Laboratory. PARTICIPANTS: Twenty-three participants with and without shoulder symptoms. MAIN OUTCOME MEASURES: Static positions of scapular upward rotation, anterior/posterior tilting and clavicular elevation were measured between days with an inclinometer and compared to a 3-dimensional electromagnetic tracking system in different positions of sagittal plane humeral elevation (neutral, 30°, 60°, 90°, 120°). The two methods were compared using a two-way Analysis of Variance. Linear regressions at each arm position were also performed to further assess concurrent validity. RESULTS: Between-day reliability demonstrated Intraclass Correlation Coefficients ≥ 0.50 for all comparisons. There were statistically significant differences between methods or interactions of method and arm position for clavicle elevation (p = 0.004, maximum offset between methods 7.7º in the neutral position), and scapular upward rotation (p = 0.001). For scapular upward rotation, the maximum difference between methods was less than 2° across all humeral positions. Clavicle elevation (r = 0.67-0.82) and scapular upward rotation (r = 0.57-0.81) demonstrated higher correlations between measurement methods than scapular anterior/posterior tilt (r = 0.10-0.67). CONCLUSIONS: Concurrent validity in assessing scapular upward rotation and clavicle elevation with an inclinometer was shown when compared with electromagnetic tracking. However, the inclinometer method may not have adequate concurrent validity to clinically measure scapular anterior/posterior tilting.

The use of evidence-based practices for the management of shoulder impingement syndrome among Indian physical therapists: a cross-sectional survey.

BACKGROUND: The understanding of the pathomechanics of shoulder impingement has evolved over the years. Likewise, assessment techniques and effective treatment strategies have also been developed. Physical therapists should keep up-to-date on the current evidence. OBJECTIVE: This study explored the practices currently used by Indian physical therapists for the assessment and management of shoulder impingement syndrome (SIS). METHOD: Using an online questionnaire, therapists were asked to declare the causes, methods of assessment and their choices of physical therapy techniques for the management of SIS. The proportions of therapists using different techniques were analyzed descriptively, and comparisons across gender, experience level, and training were made. Data were analyzed to see if the choices of respondents compared with their responses for etiology. RESULTS: A total of 211 responses were analyzed. Most respondents (>75%) believed that overuse and abnormal motion/posture are the most significant causes of SIS. However, fewer respondents reported assessing posture (60.2%) and dyskinesis, especially in women (24.2%). Ninety-four percent of the respondents reported using exercises, but exercise prescription was rather generic. Therapists additionally trained in the techniques of joint mobilization or taping declared using these techniques more frequently. The use of interferential therapy and ultrasound was reported by 89.5% and 98.4% of respondents, respectively CONCLUSION: Most therapists declared awareness of current recommended practices, but patient assessment, exercise prescription, and use of electrotherapy modalities were only partially based on current evidence. The study helps to identify gaps in current physical therapy approaches to SIS in India.

The use of evidence-based practices for the management of shoulder impingement syndrome among Indian physical therapists: a cross-sectional survey

ABSTRACT Background: The understanding of the pathomechanics of shoulder impingement has evolved over the years. Likewise, assessment techniques and effective treatment strategies have also been developed. Physical therapists should keep up-to-date on the current evidence. Objective: This study explored the practices currently used by Indian physical therapists for the assessment and management of shoulder impingement syndrome (SIS). Method: Using an online questionnaire, therapists were asked to declare the causes, methods of assessment and their choices of physical therapy techniques for the management of SIS. The proportions of therapists using different techniques were analyzed descriptively, and comparisons across gender, experience level, and training were made. Data were analyzed to see if the choices of respondents compared with their responses for etiology. Results: A total of 211 responses were analyzed. Most respondents (>75%) believed that overuse and abnormal motion/posture are the most significant causes of SIS. However, fewer respondents reported assessing posture (60.2%) and dyskinesis, especially in women (24.2%). Ninety-four percent of the respondents reported using exercises, but exercise prescription was rather generic. Therapists additionally trained in the techniques of joint mobilization or taping declared using these techniques more frequently. The use of interferential therapy and ultrasound was reported by 89.5% and 98.4% of respondents, respectively Conclusion: Most therapists declared awareness of current recommended practices, but patient assessment, exercise prescription, and use of electrotherapy modalities were only partially based on current evidence. The study helps to identify gaps in current physical therapy approaches to SIS in India.

Cardan angle rotation sequence effects on first-metatarsophalangeal joint kinematics: implications for measuring hallux valgus deformity.

BACKGROUND: There currently are no recommended standards for reporting kinematics of the first-metatarsophalangeal joint. This study compared 2 different rotation sequences of Cardan angles, with implications for understanding the measurement of hallux valgus deformity. METHODS: Thirty-one women (19 hallux valgus; 12 controls) participated. All were scanned in an open-upright magnetic resonance scanner, their foot posed to simulate the gait conditions of midstance, heel-off, and terminal stance. Using computer processes, selected tarsals were reconstructed into virtual bone models and embedded with principal-axes coordinate systems, from which the rotation matrix between the hallux and first metatarsal was decomposed into Cardan angles. Joint angles were then compared using a within factors (rotation sequence and gait condition) repeated-measures analysis of variance (ANOVA). RESULTS: Only the transverse plane-first sequence consistently output incremental increases of dorsiflexion and abduction across gait events in both groups. There was an interaction (F ≥ 25.1; p < 0.001). Follow-up comparisons revealed angles were different (p < 0.05) at terminal stance. CONCLUSIONS: Different rotation sequences yield different results. Extracting the first rotation in the transverse plane allows for the resting alignment of the hallux to deviate from the sagittal plane. Therefore, representing first-metatarsophalangeal joint kinematics with the transverse plane-first rotation sequence may be preferred, especially in cases of hallux valgus deformity.

An image-based gait simulation study of tarsal kinematics in women with hallux valgus.

BACKGROUND: Although not well understood, foot kinematics are changed with hallux valgus. OBJECTIVE: The purpose of this study was to examine tarsal kinematics in women with hallux valgus deformity. DESIGN: A prospective, cross-sectional design was used. METHODS: Twenty women with (n=10) and without (n=10) deformity participated. Data were acquired with the use of a magnetic resonance scanner. Participants were posed standing to simulate gait, with images reconstructed into virtual bone datasets. Measures taken described foot posture (hallux angle, intermetatarsal angle, arch angle). With the use of additional computer processes, the image sequence was then registered across gait conditions to compute relative tarsal position angles, first-ray angles, and helical axis parameters decomposed into X, Y, and Z components. An analysis of variance model compared kinematics between groups and across conditions. Multiple regression analysis assessed the relationship of arch angle, navicular position, and inclination of the first-ray axis. RESULTS: Both the hallux and intermetatarsal angles were larger with deformity; arch angle was not different between groups. The calcaneus was everted by ≥6.6 degrees, and the first ray adducted (F=44.17) by ≥9.3 degrees across conditions with deformity. There was an interaction (F=5.06) for the first-ray axis. Follow-up comparisons detected increased inclination of the first-ray axis over middle stance compared with late stance in the group with deformity. LIMITATIONS: Gait was simulated, kinetics were not measured, and sample size was small. CONCLUSIONS: There were group differences. Eversion of the calcaneus and adduction of the first ray were increased, and the first-ray axis was inclined 24 degrees over middle stance in women with deformity compared with 6 degrees in control participants. Results may identify risk factors of hallux valgus and inform nonoperative treatment (orthoses, exercise) strategies.

Three-dimensional shoulder kinematics after total claviculectomy: a biomechanical investigation of a single case.

Since total claviculectomy is an uncommon surgical procedure, few case reports exist in the literature. This report describes the three-dimensional scapulothoracic kinematics in a subject with unilateral total claviculectomy. Kinematic data were collected during shoulder protraction with arms at the side of the body, horizontal arm adduction at 90° of elevation, humeral internal/external rotation with the arm at 90° of elevation in the frontal plane, and elevation and lowering of the arm in the sagittal plane. Descriptive data were compared to the subject's contralateral shoulder. Scapulohumeral rhythm during arm elevation in the sagittal plane was calculated for both sides. Overall the subject demonstrated excessive scapular mobility. However, kinematics during elevation were similar to the contralateral side during elevation. The subject demonstrates good muscle control despite the lack of normal sternoclavicular and acromioclavicular joint articulations. His relatively well-preserved shoulder biomechanics belied his ongoing symptoms, especially involving pain with activities that required use of the arm away from the side.

Study of the scapular muscle latency and deactivation time in people with and without shoulder impingement.

Changes in muscle activities are commonly associated with shoulder impingement and theoretically caused by changes in motor program strategies. The purpose of this study was to assess for differences in latencies and deactivation times of scapular muscles between subjects with and without shoulder impingement. Twenty-five healthy subjects and 24 subjects with impingement symptoms were recruited. Glenohumeral kinematic data and myoelectric activities using surface electrodes from upper trapezius (UT), lower trapezius (LT), serratus anterior (SA) and anterior fibers of deltoid were collected as subjects raised and lowered their arm in response to a visual cue. Data were collected during unloaded, loaded and after repetitive arm raising motion conditions. The variables were analyzed using 2 or 3 way mixed model ANOVAs. Subjects with impingement demonstrated significantly earlier contraction of UT while raising in the unloaded condition and an earlier deactivation of SA across all conditions during lowering of the arm. All subjects exhibited an earlier activation and delayed deactivation of LT and SA in conditions with a weight held in hand. The subjects with impingement showed some significant differences to indicate possible differences in motor control strategies. Rehabilitation measures should consider appropriate training measures to improve movement patterns and muscle control.

The accuracy of measuring glenohumeral motion with a surface humeral cuff.

Conclusions about normal and pathologic shoulder motion are frequently made from studies using skin surface markers, yet accuracy of such sensors representing humeral motion is not well known. Nineteen subjects were investigated with flock of birds electromagnetic sensors attached to transcortical pins placed into the scapula and humerus, and a thermoplastic cuff secured on the arm. Subjects completed two repetitions of raising and lowering the arm in the sagittal, scapular and coronal planes, as well as shoulder internal and external rotation with the elbow at the side and abducted to 90°. Humeral motion was recorded simultaneously from surface and bone fixed sensors. The average magnitude of error was calculated for the surface and bone fixed measurements throughout the range of motion. ANOVA tested for differences across angles of elevation, raising and lowering, and differences in body mass index. For all five motions tested, the plane of elevation rotation average absolute error ranged from 0-2°, while the humeral elevation rotation average error ranged from 0-4°. The axial rotation average absolute error was much greater, ranging from 5° during elevation motions to approaching 30° at maximum excursion of internal/external rotation motions. Average absolute error was greater in subjects with body mass index greater than 25. Surface sensors are an accurate way of measuring humeral elevation rotations and plane of elevation rotations. Conversely, there is a large amount of average error for axial rotations when using a humeral cuff to measure glenohumeral internal/external rotation as the primary motion.

Comparison of glenohumeral motion using different rotation sequences.

Glenohumeral motion presents challenges for its accurate description across all available ranges of motion using conventional Euler/Cardan angle sequences without singularity. A comparison of the description of glenohumeral motion was made using the ISB recommended YX'Y″ sequence to the XZ'Y″ sequence. A direct in-vivo method was used for the analysis of dynamic concentric glenohumeral joint motion in the scapular plane. An electromagnetic tracking system collected data from ten healthy individuals while raising their arm. There were differences in the description of angular position data between the two different sequences. The YX'Y″ sequence described the humerus to be in a more anteriorly rotated and externally rotated position compared to XZ'Y″ sequence, especially, at lower elevation angles. The description of motion between increments using XZ'Y″ sequence displacement decomposition was comparable to helical angles in magnitude and direction for the study of arm elevation in the scapular plane. The description of the direction or path of motion of the plane of elevation using YX'Y″ angle decomposition would be contrary to that obtained using helical angles. We recommend that this alternate sequence (XZ'Y″) should be considered for describing glenohumeral motion.

Three-dimensional in vivo kinematics of an osteoarthritic shoulder before and after total shoulder arthroplasty.

A case of a patient with glenohumeral joint arthritis is presented which demonstrated the three-dimensional shoulder motion before and after total shoulder arthroplasty. Pre-operative shoulder motion differed compared to normal controls, while post-operatively her glenohumeral-to-scapulothoracic motion ratios were restored to near normal ratios.

Motion of the shoulder complex during multiplanar humeral elevation.

BACKGROUND: Many prior studies have evaluated shoulder motion, yet no three-dimensional analysis comparing the combined clavicular, scapular, and humeral motion during arm elevation has been done. We aimed to describe and compare dynamic three-dimensional motion of the shoulder complex during raising and lowering the arm across three distinct elevation planes (flexion, scapular plane abduction, and coronal plane abduction). METHODS: Twelve subjects without a shoulder abnormality were enrolled. Transcortical pin placement into the clavicle, scapula, and humerus allowed electromagnetic motion sensors to be rigidly fixed. The subjects completed two repetitions of raising and lowering the arm in flexion, scapular, and abduction planes. Three-dimensional angles were calculated for sternoclavicular, acromioclavicular, scapulothoracic, and glenohumeral joint motions. Joint angles between humeral elevation planes and between raising and lowering of the arm were compared. RESULTS: General patterns of shoulder motion observed during humeral elevation were clavicular elevation, retraction, and posterior axial rotation; scapular internal rotation, upward rotation, and posterior tilting relative to the clavicle; and glenohumeral elevation and external rotation. Clavicular posterior rotation predominated at the sternoclavicular joint (average, 31 degrees). Scapular posterior tilting predominated at the acromioclavicular joint (average, 19 degrees). Differences between flexion and abduction planes of humerothoracic elevation were largest for the glenohumeral joint plane of elevation (average, 46 degrees). CONCLUSIONS: Overall shoulder motion consists of substantial angular rotations at each of the four shoulder joints, enabling the multiple-joint interaction required to elevate the arm overhead.

Arch height and first metatarsal joint axis orientation as related variables in foot structure and function.

BACKGROUND: This study investigated the association of arch height combined with first metatarsal joint axis vertical (V) orientation to the size of the 1-2 intermetatarsal angle (IMA) and first metatarsal adduction/abduction position simulating foot postures during gait, kinematics commonly affected by bunion. MATERIALS AND METHODS: Nine cadaver specimens were mounted in a loading frame. Measures of arch height ratio and IMA were made. With the foot placed in positions seen during normal gait cycle an electromagnetic device measured displacement of the relative angle of rotations between the first metatarsal and navicular, and helical axis (HA) parameters. Canonical correlation analysis assessed the relationship among the variables. RESULTS: A negative relationship (r = -0.73) was found between arch height and first metatarsal HA V-orientation. When considered as combined variables, arch height and metatarsal HA V-orientation accounted for 69% of the variance of IMA and change in first metatarsal adduction/abduction position. CONCLUSION: Orientation of the first metatarsal joint axis was highly variable between specimens but correlated with arch height. The conjoined factors of arch height and first metatarsal HA V-orientation accounted for most of the variance of IMA and change in first metatarsal adduction/abduction position during the sequence of foot position during simulated gait. CLINICAL RELEVANCE: These findings suggest that orthotic arch support could reorient the metatarsal joint axis out-of-vertical and in effect, limit the first metatarsal from displacing into an adducted bunion deformity. These findings could help to explain the pathogenesis of bunions.