Progression Angle Research Articles

Remotely delivered, individualized, and self-directed gait modification for knee osteoarthritis: A pilot trial

BackgroundGait modification interventions have reported variable results and relied on in-person biofeedback limiting clinical accessibility. Our objective was to assess a remotely delivered and self-directed gait modification for knee osteoarthritis. MethodsThis was an unblinded, 2-arm, delayed control, randomized pilot trial (NCT04683913). Adults aged ≥50 years with symptomatic medial knee osteoarthritis were randomized to an immediate group (Week 0: Baseline, Intervention; Week 6: Follow-up, Week 10: Retention) or delayed group (Week 0: Baseline, Wait Period, Week 6: Secondary Baseline, Intervention, Week 12: Follow-up, Week 16: Retention). Participants practiced modifying their foot progression angle “as much as was comfortable” while receiving support via weekly telerehabilitation appointments and remote monitoring with an instrumented shoe. Primary outcomes included participation, foot progression angle modification magnitude, confidence, difficulty, and satisfaction while secondary outcomes included symptoms and knee biomechanics during gait. ResultsWe screened 134 people and randomized 20. There was no loss to follow up and 100% attendance at the telerehabilitation appointments. By follow up, participants reported high confidence (8.6/10), low difficulty (2.0/10), and satisfaction (75%) with the intervention and no significant adverse events. Foot progression angle was modified by 11.4° ± 5.6, which was significantly different (p < 0.001, η2g = 0.8) when compared between groups. No other between-group differences were significant, while several significant pre-post improvements in pain (d = 0.6, p = 0.006) and knee moments (d = 0.6, p = 0.01) were observed. InterpretationA personalized, self-directed gait modification supported with telerehabilitation is feasible, and the preliminary effects on symptoms and biomechanics align with past trials. A larger trial is warranted to evaluate efficacy.

Multi-day monitoring of foot progression angles during unsupervised, real-world walking in people with and without knee osteoarthritis

BackgroundFoot progression angle is a biomechanical target in gait modification interventions for knee osteoarthritis. To date, it has only been evaluated within laboratory settings. MethodsAdults with symptomatic knee osteoarthritis (n = 30) and healthy adults (n = 15) completed two conditions: 1) treadmill walking in the laboratory (5-min), and 2) real-world walking outside of the laboratory (1-week). Foot progression angle was estimated via shoe-embedded inertial sensing. We calculated the foot progression angle magnitude (median) and variability (interquartile range, coefficient of variation), and used mixed models to compare outcomes between the conditions, participant groups, and disease severities. Reliability was quantified by the intraclass correlation coefficient, standardized error of the measurement, and the minimum detectable change. FindingsFoot progression angle magnitude did not differ between groups or conditions but variability significantly higher in real-world walking (P < 0.001). Structural and symptomatic severity were unrelated to FPA in either walking condition, except for real-world coefficient of variation which was higher for moderate-severe structural osteoarthritis compared to the treadmill for those with mild structural severity (P < 0.034). All real-world outcomes showed excellent reliability including intraclass correlation coefficients above 0.95. The participants recorded a mean (standard deviation) of 298 (33) and 10,447 (5232) steps in the laboratory and real-world walking conditions, respectively. InterpretationThis study provides the first characterization of foot progression angles during real-world walking in people with and without symptomatic knee osteoarthritis. These results indicate that foot progression angles can be feasibly and reliably measured in unsupervised real-world walking conditions.

Estimation of Stride Length, Foot Clearance, and Foot Progression Angle Using UWB Sensors

Stride length (SL), foot clearance (FC), and foot progression angle (FPA) are the key parameters for diagnosing gait disorders. This study used the distance data between two feet measured by ultra-wideband (UWB) sensors installed on shoes and proposed a method for estimating the three gait parameters. Here, a method of compensating the offset of the UWB sensor and estimating the distances between a base sensor installed on one foot during the stance phase and three UWB sensors on the other during the swing phase was applied. Foot trajectory was acquired in a gait experiment with ten healthy adults walking on a treadmill. The results were compared with those obtained using a motion capture system (MCS). The UWBs sensor displayed average errors of 45.84 mm, 7.60 mm, and 2.82° for SL, FC, and FPA, respectively, compared with the MCS. A similar accuracy level was achieved in a previous study that used an inertial measurement unit (IMU). Thus, these results suggest that UWB sensors can be extensively applied to sensor systems used to analyze mobile gait systems.

Intrapartum ultrasound in maternal lateral versus semi-recumbent posture. A repeated measures study

ObjectiveThis study aimed to assess whether intrapartum ultrasound (ITU) measurements in maternal lateral posture are superimposable to ITU measurements in semi-recumbent position. Study designA single-center, repeated measures design was used. Women in the second stage of labor were randomized to ITU first in semi-recumbent followed by ITU in side-lying posture without and with contraction, or inversely.The angle of progression (AOP) and the head-perineum distance (HPD) between contractions (AOP1 and HPD1) and with contraction (AOP2 and HPD2) were measured in each maternal posture. The differences between AOP1 and AOP2 (dAOP), and between HPD1 and HPD2 (dHPD) were calculated. Results and conclusionsForty-two women participated in the study. A generalized estimating equation model showed that AOP1 (-3.00°; 95 % CI −5.77 to −0.23; p = 0.03) and AOP2 (-4.14°; 95 % CI −7.20 to −1.08; p = 0.008) were lower in semi-recumbent compared to maternal lateral posture. HPD1 (+1.43 mm; 95 % CI 0.05–2.81; p = 0.042) and HPD2 (+1.53 mm; 95 % CI 0.17–2.89; p = 0.03) were higher in semi-recumbent position.Differences in the ITU measurements in maternal lateral posture compared to semi-recumbent position are small. Monitoring the second stage of labor with ITU in lateral maternal posture is possible.

Assessment of the angle of progression and head-perineum distance in the prediction of type of delivery and duration of second stage of labor using intrapartum transperineal ultrasonography

Background: Each pregnancy's straightforward goal is to deliver a healthy baby to a healthy mother. Prolonged second stages of labour have been linked to poor mother and neonatal outcomes. The gold standard for diagnosing head descent clinically is still a digital transvaginal examination. Head station is based on the relationship between the ischial spine and the leading edge of the foetal head in the maternal pelvis. The intrapartum transperineal ultrasonography is a safe method for determining the position of the foetal head and for anticipating the course of the delivery. It is very useful in analyzing phenomena connected to the transit of the foetus through the birth canal.Aims: This study's objective is to assess the effectiveness of intrapartum transperineal ultrasound in predicting the kind of birth and length of the second stage of labour by assessing parameters for the Angel of Progression and Head Perineum Distance.Patients and Methods: Cross-sectional prospective research is the study's design. At Tanta University Hospitals' Department of Obstetrics inpatient ward, 65 primigravida women participated in the study. commenced in August 2021 and concluded in August 2022.Results: According to our findings, there was a positive highly statistically significant correlation between AOP and vaginal delivery patients compared to CS delivery patients, while there was a negative highly statistically significant correlation between HPD and vaginal delivery patients compared to CS delivery patients. A positive highly statistically significant association was found between the length of the second stage and the HPD, while a negative highly statistically significant correlation was found between the length of the second stage and the angle of progression.Conclusion: Intrapartum ultrasound has been used to measure a number of characteristics, including the angle of progression (AOP) and head-perineum distance (HPD). The manner of delivery and length of pushing can be predicted with the help of an ultrasound conducted at the start of the active second stage of labour.

Commentary: Reliability, repeatability, and accuracy of Sirius topographer in assessing anterior segment morphology following laser peripheral iridotomy in primary angle-closure disease.

Commentary: Reliability, repeatability, and accuracy of Sirius topographer in assessing anterior segment morphology following laser peripheral iridotomy in primary angle-closure disease.

Sex-Specific associations between hip muscle strength and foot progression angle.

The foot progression angle (FPA) influences knee loading during gait, but its determinants are unclear. The purpose of this study was to compare FPA between males and females and also examine the association between lower extremity kinematics during gait, hip strength, and the FPA. 25 males and 25 females completed 5 gait trials while FPA and frontal and transverse plane hip and knee angles were calculated from the dominant limb during the foot flat portion of stance. Hip extensor/flexor, abductor/adductor, and internal/external rotator strength were evaluated using maximum voluntary isometric contractions. One-way MANOVAs compared gait and strength outcomes. Stepwise regression assessed the association between FPA, and MVIC and kinematics after accounting for speed in males and females. There was no difference in FPA between sexes (p>0.05), but females had greater frontal and transverse plane hip angles compared with males (all p<0.05). Greater hip abduction (p=0.02) strength was associated with greater FPA, but only in males. In males, greater hip abductor strength may contribute to a more neutral position of the foot during gait, which could help maintain an equal knee loading distribution. Our results suggest that there are sex specific control strategies to achieve a similar FPA during gait.

Reliability and Reproducibility of Analyzing 3D Transperineal Ultrasound Volumes Obtained in the First Phase of Labor - A Pilot Study.

The aim of this study was to investigate the reliability and reproducibility of transperineal ultrasound (TPUS) in the initial phase of labor. As TPUS is a common method, it could supplement vaginal palpation and even replace it in certain situations. In addition, we used a 4-dimensional method for the assessment of cervical effacement. 54 women in labor were included and underwent TPUS. The resulting images from the acquired 4D volumes were evaluated after the examination for the first time and a second time after 21 days. The measured values were cervical length, dilatation and effacement, the angle of progression (AoP), and head-perineum distance. 54 patients were examined. TPUS images were unable to be evaluated in 12 patients because of cervical dilatation of more than 5 cm or poor image quality. Thus, 42 measurements were included. The concordance correlation coefficients according to Lin are satisfactory overall, with one exception for cervical effacement. The accuracy component of cervical length (CCCLin: 0.93; accuracy: 1.00), dilatation (CCCLin: 0.93; accuracy: 1.00), and AoP (CCCLin: 0.87; accuracy: 1.00) is excellent and still high for the head-perineum distance (CCCLin: 0.89; accuracy: 0.96) and cervical effacement (CCCLin: 0.77; accuracy: 0.97). TPUS is a valuable noninvasive tool with good diagnostic accuracy for the AoP, cervical length, and dilatation. Our study provides support for the use of TPUS to complement a vaginal examination. It should not replace a digital examination but should serve as a suitable alternative method for monitoring labor progression in the future.

Changes in gait pattern and quality of life of adolescents with flexible flat foot after Calcaneal Lengthening Osteotomy

BackgroundCalcaneal Lengthening Osteotomy is a surgical technique to correct flexible flat foot deformities in patients who did not show any change in their symptoms after conservative treatment. In this study, the effects of CLO on the kinematic and kinetic changes of gait was analyzed and the clinical and quality of life improvements in children treated by CLO for moderate to severe symptomatic flexible flat foot deformities were assessed. MethodsParticipants were seven adolescents (13 feet) with symptomatic FFF who underwent during 2019–2022 and seven (10 feet) healthy children as control group. Three items were evaluated in each foot before and after surgery including: 1. Clinical examination 2.quality of life (using Pediatric Quality of Life Inventory version 4 questionnaire) 3. Gait analysis (Vicon motion systems, Oxford metrics Inc., UK). Also, the kinetic and kinematic analysis between patients and healthy groups were compared. ResultsKinematic results of control was significantly better than FFF group. Ankle range of motion(32.94 ± 13.39 compared to 32.94 ± 13.39,P-Value:0.01),foot progression angle (−9.26 ± 7.67 compared to −16.07 ± 9.00,P-Value:0.01),and internal rotation of ankle was higher in control group compared to FFF. FFF patients demonstrated improvement in kinematic results after CLO surgery. Foot progression angle was improved after surgery (−11.31 ± 6.07 compared to −16.19 ± 7.06, P-value:0.00), maximum plantar flexion decreased after CLO surgery due to achil tendon procedure during CLO surgery. Kinetic results of FFF patients showed significant increase in ankle Power in coronal and transverse plane, Also knee and hip power showed similar results.Quality of life parameters showed significant improve in all parameters (Physical,Social, emotional and school function), Also ADKE and ADKF improved after surgery. ConclusionCLO surgery significantly improved patients' quality of life of patients with symptomatic FFF. Also, kinetic results showed improvement in some parameters of gait results after CLO surgery. Thus, our study suggested CLO surgery as an excellent surgical option for symptomatic FFF.

The success of vaginal birth by use of trans-labial ultrasound plus vaginal examination and vaginal examination only in pregnant women with labor induction: a comparative study

BackgroundPredicting the success of vaginal delivery is an important issue in preventing adverse maternal and neonatal outcomes. Thus, this study aimed to compare the success rate of vaginal birth by using trans-labial ultrasound and vaginal examination, and vaginal examination only in pregnant women with labor induction.MethodsThis was a comparative study including 392 eligible pregnant women with labor induction attending to a teaching hospital affiliated with Iran University of Medical Sciences from April to October 2018 in Tehran, Iran. Women were randomly assigned to two groups; the trans-labial ultrasound plus vaginal examination (group A), and the vaginal examination only (group B). Women were included in the study if they satisfied the following criteria: singleton pregnancy, 37 to 42 weeks of gestational age, fetal head presentation, a living fetus with no abnormalities, uncomplicated pregnancy, and no previous cesarean section or any uterine surgery. We used a partograph for both groups to assess the fetal head position and the fetal head station. In group 1, the Angle of Progression (AoP) and Rotation Angle (RA) were also assessed. Finally, the success and progression of vaginal delivery in two groups were compared by predicting the duration of delivery and mode of delivery.ResultsThe findings showed that 8.68% of women in the trans-labial plus vaginal examination group delivered by cesarean section, while 6.13% in the vaginal examination only group delivered by cesarean section (P = 0.55). In women with cesarean section in positive fetal head stations, Angle of Progression (AoP) was significantly decreased ranging from 90 to 135 degrees compared to women who delivered vaginally (135–180 degrees; P < 0.001). In addition, the Rotation Angle (RA) was significantly decreased in women with cesarean section ranging from 0 to 30 degrees compared to women who delivered vaginally (60-90degrees; P < 0.001). Further analysis indicated that a higher risk of cesarean section was associated with vaginal examination only as compared to trans-labial ultrasound plus vaginal examination (HR: 8.65, P < 0.001).ConclusionAngle of Progression (AoP) and Rotation Angle (RA) indexes might be useful parameters to predict labor progression and successful vaginal delivery among women undergoing labor induction.

Effect of foot progression angle alteration on medial-lateral center of pressure position during single-leg standing.

[Purpose] This study aimed to investigate the effect of altering the foot progression angle (FPA) on the center of pressure (COP) position during single-leg standing. [Participants and Methods] Fifteen healthy adult males participated. The participants performed single-leg standing on the left leg in three different FPA conditions, namely toe-in, neutral, and toe-out, in which the FPA was set to 0°, 10°, and 20°, respectively. The COP positions and pelvis angles were measured using a 3D motion analysis system, and each measurement value among the three conditions was compared. [Results] The medial-lateral COP position differed among conditions in the coordinate system based on the laboratory condition but did not differ in the coordinate system based on the longitudinal axis of the foot segment. Moreover, no changes were observed in pelvis angles that would affect COP position. [Conclusion] Altering the FPA does not change the medial-lateral position of the COP during single-leg standing. Here we show that COP displacement based on the laboratory coordinate system is involved in the mechanism-linking alteration of FPA and changes in knee adduction moment.

Delivering Load-Modifying Gait Retraining Interventions via Telehealth in People With Medial Knee Osteoarthritis: A Pilot Randomized Placebo-Controlled Clinical Trial.

We aimed to investigate the effects of delivering 3 gait retraining interventions (toe-in, toe-out, and placebo gait) on proxy measures of medial knee load (early- and late-stance peak knee adduction moment [KAM], KAM impulse, and varus thrust) in people with knee osteoarthritis, using a hybrid model of face-to-face and telehealth-delivered sessions over 5 months. This was an originally planned 3-arm randomized placebo-controlled clinical trial. However, during the 2021 COVID-19 outbreak and lockdown in Sydney, Australia, the study became a pilot randomized controlled trial with the remainder of interventions delivered via telehealth. Nine individuals with symptomatic medial knee osteoarthritis were allocated to receive either a toe-in, toe-out, or posture re-education (placebo) gait retraining intervention. Primary outcomes of early- and late-stance peak KAM, KAM impulse, and varus thrust were assessed at baseline and follow-up. Eight participants returned for their follow-up gait assessment. Participants in both active intervention groups (toe-in and toe-out) achieved foot progression angle changes at follow-up. Overall, knee biomechanics in the placebo group did not change at follow-up. It is possible to achieve biomechanical changes in individuals with medial knee osteoarthritis when delivering gait retraining interventions via a hybrid model of face-to-face and telehealth.

Orthopaedic Diagnoses in the Black Pediatric Population.

The Black pediatric population is one that has been historically underserved and continues to have unmet needs. Factors including lack of diversity in orthopaedic studies and in historical standards, such as bone age, may inadvertently lead to inferior care. There are certain conditions in this population for which the practicing orthopaedic surgeon should have a higher degree of suspicion, including slipped capital femoral epiphysis, Blount disease, and postaxial polydactyly. Systemic diseases with higher rates in this population have orthopaedic manifestations, including sickle cell disease, vitamin D deficiency, and obesity. Racial discrepancies in access to prenatal care can have orthopaedic consequences for babies, especially cerebral palsy and myelodysplasia. Racial discrepancy exists in evaluation for nonaccidental trauma. Increased awareness of these issues better prepares practitioners to provide equitable care.

A framework for computing angle of progression from transperineal ultrasound images for evaluating fetal head descent using a novel double branch network.

Background: Accurate assessment of fetal descent by monitoring the fetal head (FH) station remains a clinical challenge in guiding obstetric management. Angle of progression (AoP) has been suggested to be a reliable and reproducible parameter for the assessment of FH descent. Methods: A novel framework, including image segmentation, target fitting and AoP calculation, is proposed for evaluating fetal descent. For image segmentation, this study presents a novel double branch segmentation network (DBSN), which consists of two parts: an encoding part receives image input, and a decoding part composed of deformable convolutional blocks and ordinary convolutional blocks. The decoding part includes the lower and upper branches, and the feature map of the lower branch is used as the input of the upper branch to assist the upper branch in decoding after being constrained by the attention gate (AG). Given an original transperineal ultrasound (TPU) image, areas of the pubic symphysis (PS) and FH are firstly segmented using the proposed DBSN, the ellipse contours of segmented regions are secondly fitted with the least square method, and three endpoints are finally determined for calculating AoP. Results: Our private dataset with 313 transperineal ultrasound (TPU) images was used for model evaluation with 5-fold cross-validation. The proposed method achieves the highest Dice coefficient (93.4%), the smallest Average Surface Distance (6.268 pixels) and the lowest AoP difference (5.993°) by comparing four state-of-the-art methods. Similar results (Dice coefficient: 91.7%, Average Surface Distance: 7.729 pixels: AoP difference: 5.110°) were obtained on a public dataset with >3,700 TPU images for evaluating its generalization performance. Conclusion: The proposed framework may be used for the automatic measurement of AoP with high accuracy and generalization performance. However, its clinical availability needs to be further evaluated.

Pathological gait in partial foot amputation versus peripheral neuropathy

Partial foot amputation (PFA) is a common surgical loss of part of either the forefoot or mid-foot. It is usually the sequel to a cascade of physiological foot dysfunction such as peripheral neuropathy (PN). The gait compensation mechanisms associated with these foot disorders aren’t well understood yet. PurposeThe aim of the study was to evaluate pathological gait compensation mechanisms in PFA due to PN versus PN alone through a comprehensive gait analysis. MethodsPlantar pressure, GRF, load distribution, footprint length and area, foot progression angle, step length, percentage of double limb support, and stance time were measured on 53 participants assigned into two well-matched groups: (A) 25 subjects with healed unilateral PFA and (B) 28 subjects with PN without ulcer. The gait analysis was conducted at a self-preferred walking speed using the FREEMED baropodometric platform and FREESTEP software. ResultsThe PFA group showed a significant decrease in load over the remaining toes and metatarsal heads compared to the PN group (p = .001 and p = .003, respectively). Conversely, the PFA group showed a significant increase in load over the mid-foot and peak plantar pressure during mid-stance (p = .007 and p = .016, respectively). All other measured variables showed no significant difference between the two groups (p > .05). ConclusionIndividuals with PFA and PN or PN alone tend to shift their body loads posteriorly and redistribute their loads to compensate for the insufficient support from the forefoot. The PFA group was worse than the PN group. Furthermore, the PFA may not be the primary cause of the altered gait but rather the underlying systemic disease. The PFA surgery only worsens the compensatory mechanism.

The Relationship between Frontal, Axial Leg Alignment, and Ankle Joint Line Orientation-a Radiographic Analysis of Healthy Subjects.

Ankle joint line orientation (AJLO) is influenced by the subtalar foot and frontal leg alignment. However, the influence of axial leg alignment on AJLO remains unclear. The study aimed to analyze the influence of frontal, axial leg alignment on AJLO in healthy subjects. Thirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph (LLR) between 2016 and 2020. AJLO was measured in standing long-leg radiographs relative to the ground. Meary's angle and calcaneal pitch were measured. Hip-knee-ankle angle (HKA), femoral antetorsion, and tibial torsion were assessed with SterEOS software (EOS Imaging, Paris, France). LLR was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of subtalar, frontal, and axial alignment on AJLO was analyzed in a multiple regression model. An increase in knee valgus increased relative valgus AJLO by 0.5° (95% CI: 0.2° to 0.7°) per 1° (P < 0.001). A decrease in femoral antetorsion increased relative valgus AJLO by 0.2° (95% CI: 0.1° to 0.2°) per 1° (P < 0.001), whereas Meary's angle and calcaneal pitch did not influence AJLO. A link between frontal, axial leg alignment, and AJLO could be demonstrated, indicating that a valgus leg alignment and relative femoral retrotorsion are associated with an increase of valgus AJLO in healthy subjects when placing their feet in a neutral position. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the AJLO, when the FPA is kept constant.

The relationship between pelvic tilt, frontal, and axial leg alignment in healthy subjects

IntroductionThe relationship between anterior pelvic tilt and overall sagittal alignment has been well-described previously. However, the relationship between pelvic tilt, frontal, and axial leg alignment remains unclear. The aim of the study was to analyze the relationship between pelvic tilt and frontal and axial leg alignment in healthy subjects. Material and methodsThirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph. Pelvic parameters (pelvic tilt, pelvic incidence, sacral slope), hip-knee-ankle angle (HKA), femoral antetorsion and tibial torsion were measured using SterEOS (EOS Imaging) software. EOS was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of HKA, femoral antetorsion, tibial torsion and gender on pelvic tilt was analyzed in a univariate correlation and multiple regression model. ResultsSixteen female subjects and 14 male subjects with a mean age of 27.1 years ± 10 (range 20–67) were included. HKA, femoral antetorsion, and tibial torsion correlated with anterior pelvic tilt in univariate analysis (all p < 0.05). Anterior pelvic tilt increased 1.1° (95% CI: 0.7 to 1.5) per 1° of knee valgus (p < 0.001) and 0.5° (95% CI: 0.3 to 0.7) per 1° of external tibial torsion (p < 0.001). Overall, linear regression model fit explained 39% of variance in pelvic tilt by the HKA, femoral antetorsion and tibial torsion (R2 = 0.385; p < 0.001). ConclusionValgus alignment and increasing tibial torsion demonstrated a weak correlation with an increase in anterior pelvic tilt in healthy subjects when placing their feet anteriorly. The relationship between frontal, axial leg alignment and pelvic tilt needs to be considered in patients with multiple joint disorders at the hip, knee and spine. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the pelvic tilt when the FPA is kept constant.

Effects of a six-week gait retraining intervention on knee load in people with medial knee osteoarthritis- A pilot study

Introduction: Gait retraining through toeing-in or toeing-out has demonstrated proportional loading effects on the knee adduction moment (KAM), a surrogate measure of knee load in people with medial knee osteoarthritis (OA). However, the evidence is limited by a lack of randomised control trial (RCT) data that directly compares the effects of both foot progression angle (FPA) interventions over six-weeks. The aim of this pilot was to identify which intervention is most effective in reducing early stance peak KAM, late stance peak KAM and KAM impulse over six-weeks.

Tibial torsion and pressures in the feet during walking: Implications for patterns of metatarsal robusticity.

The Dmanisi Homo fossils include a tibia with a low degree of torsion and metatarsals with a pattern of robusticity differing from modern humans. It has been proposed that low tibial torsion would cause a low foot progression angle (FPA) in walking, and consequently increased force applied to the medial rays. This could explain the more robust MT III and IV from Dmanisi. Here we experimentally tested these hypothesized biomechanical relationships in living human subjects. We measured transmalleolar axis (TMA, a proxy for tibial torsion), FPA, and plantar pressure distributions during walking in young men (n=40). TMA was measured externally using a newly developed method. A pressure mat recorded FPA and pressure under the metatarsal heads (MT I vs. MT II-IV vs. MT V). TMA is positively correlated with FPA, but only in the right foot. Plantar pressure under MT II-IV does increase with lower TMA, as predicted, but FPA does not affect pressure. Body mass index also influenced plantar pressure distribution. Lower tibial torsion in humans is associated with slightly increased pressures along the middle rays of the foot during walking, but not because of changes in FPA. Therefore, it is possible that the low degree of torsion in the Dmanisi Homo tibia is related to the unusual pattern of robusticity in the associated metatarsals, but the mechanism behind this relationship is unclear. Future work will explore TMA, FPA, and plantar pressures during running.

Verification of gait analysis method fusing camera-based pose estimation and an IMU sensor in various gait conditions

A markerless gait analysis system can measure useful gait metrics to determine effective clinical treatment. Although this gait analysis system does not require a large space, several markers, or time constraints, it inaccurately measure lower limb joint kinematics during gait. In particular, it has a substantial ankle joint angle error. In this study, we investigated the markerless gait analysis method capability using single RGB camera-based pose estimation by OpenPose (OP) and an inertial measurement unit (IMU) sensor on the foot segment to measure ankle joint kinematics under various gait conditions. Sixteen healthy young adult males participated in the study. We compared temporo-spatial parameters and lower limb joint angles during four gait conditions with varying gait speeds and foot progression angles. These were measured by optoelectronic motion capture, markerless gait analysis method using OP, and proposed method using OP and IMU. We found that the proposed method using OP and an IMU significantly decreased the mean absolute errors of peak ankle joint angles compared with OP in the four gait conditions. The proposed method has the potential to measure temporo-spatial gait parameters and lower limb joint angles, including ankle angles, in various gait conditions as a clinical settings gait assessment tool.