Transverse plane motion at the ankle joint

Sagittal and transverse ankle angle coupling can influence prosthetic socket transverse plane moments

Introduction

The intact foot and ankle comprise a complex set of joints that allow rotation in multiple planes of motion. Some of these motions are coupled, meaning rotation in one plane induces motion in another. One such coupling is between the sagittal and transverse planes. For every step, plantar- and dorsi-flexion motion is coupled with external and internal rotation of the shank relative to the foot, respectively. There is no prosthetic foot available for prescription that mimics this natural coupling. The purpose of this study was to determine if a sagittal:transverse ankle angle coupling ratio exists that minimizes the peak transverse plane moment during prosthetic limb stance.

Methods

A novel, torsionally active prosthesis (TAP) was used to couple sagittal and transverse plane motions using a 60-watt motor. An embedded controller generated transverse plane rotation trajectories proportional to sagittal plane ankle angles corresponding to sagittal:transverse coupling ratios of 1:0 (rigid coupling analogous to the standard-of-care), 6:1, 4:1, 3:1, and 2:1. Individuals with unilateral transtibial amputation were block randomized to walk in a straight line and in both directions around a 2 m circle at their self-selected speed with the TAP set at randomized coupling ratios. The primary outcome was the peak transverse plane moment, normalized to body mass, during prosthetic limb stance. Secondary outcomes included gait biomechanic metrics and a measure of satisfaction.

Results

Eleven individuals with unilateral transtibial amputations participated in the study. The 6:1 coupling ratio resulted in reduced peak transverse plane moments in pairwise comparisons with 3:1 and 2:1 coupling ratios while walking in a straight line and with the prosthesis on the outside of the circle (p < .05). Coupling ratio had no effect on gait biomechanic metrics or satisfaction.

Discussion

The general pattern of results suggests a quadratic relationship between the peak transverse plane moment and coupling ratio with a minimum at the 6:1 coupling ratio. The coupling ratio did not appear to adversely affect propulsion or body support. Subjects indicated they found all coupling ratios to be comfortable. While a mechatronic prosthesis like the TAP may have limited commercial potential, our future work includes testing a robust, passive prosthetic foot with a fixed coupling ratio.

Impacts of Stroke on Muscle Perceptions and Relationships with the Motor and Functional Performance of the Lower Extremities

Stroke results in paretic limb disabilities, but few studies have investigated the impacts of stroke on muscle perception deficits in multiaxis movements and related functional changes. Therefore, this study aimed to investigate stroke-related changes in muscle perceptions using a multiaxis ankle haptic interface and analyze their relationships with various functions. Sixteen stroke patients and 22 healthy participants performed active reproduction tests in multiaxis movements involving the tibialis anterior (TA), extensor digitorum longus (EDL), peroneus longus, and flexor digitorum longus (FDL) of the ankle joint. The direction error (DE), absolute error (AE), and variable error (VE) were calculated. The lower extremity of Fugl-Meyer Assessment (FMA-LE), Barthel Index (BI), Postural Assessment Scale for Stroke Patients, Tinetti Performance-Oriented Mobility Assessment (POMA), and 10-m walk test (10MWT) were evaluated. VE of EDL for the paretic ankle was significantly lower than that for the nonparetic ankle (p = 0.009). AE of TA, EDL, and FDL and VE of EDL and FDL of muscle perceptions were significantly lower in healthy participants than in stroke patients (p < 0.05 for both). DE of TA for the paretic ankle was moderately correlated with FMA-LE (r = -0.509) and POMA (r = -0.619) scores. AE and VE of EDL for the paretic ankle were moderately correlated with the 10MWT score (r = 0.515 vs. 0.557). AE of FDL for the paretic ankle was also moderately correlated with BI (r = -0.562). This study indicated poorer accuracy and consistency in muscle perception for paretic ankles, which correlated with lower limb functions of stroke patients.

Prevalence and Pattern of Musculoskeletal Injuries Among Malaysian Hockey League Players

Introduction

Hockey is a team sport that involves running, sprinting, and making sudden changes in directions of movement to control a ball against the opposing team. Therefore, due to its nature of fast movement, hockey players may be at risk of various musculoskeletal injuries. This study aimed to identify the prevalence and pattern of musculoskeletal injuries sustained among Malaysian Hockey League players.

Materials and Method

Data were collected from 84 field hockey players that participated in the Malaysian Hockey League competition from June 2016 until December 2016. All injuries were recorded by the participating medical team using a structured questionnaire. A descriptive statistical analysis and Chi-Square test were used to explore the prevalence of the injury.

Result

More than half of the players were reported to have lower limb injuries (51.6%). Sprain and strain were the most prevalent injuries (63%) and mostly affected the ankle (29%). Male players sustained more injuries (50.8%) compared to female players (49.2%).

Conclusion

This study suggests that a guideline is needed for injury prevention strategies that will benefit the hockey players in preventing injuries.

Effect of ball position on the risk of injury to the lower limb joints during the hockey sweep pass in women

Objectives

This study aimed to determine if ball position influences the risk of lower limb non-contact injury in hockey sweep pass. It also aimed to determine a ball position that minimises excessive strain placed on the lower limb joints of the lead leg during the sweep pass.

Methods

A cohort of 18 female hockey-playing volunteers (age: 19.7±1.5 years; height: 165.5±5.4 cm; body mass: 66.4±7.0 kg) were recruited. Participants performed the sweep pass using three different ball positions: in front, in line with, and behind the heel of the lead (left) foot.

Motion analysis and force plate data were collected. Moments and angles in all three planes of motion for the three main lower limb joints were then calculated using Vicon software. Results were statistically analysed using SPSS software.

Results

Significant differences (p<0.05) were found between the three tested ball positions for the mean maximum angles and moments, and mean ranges of motion produced at the lead three main lower limb joints. Positioning the ball in line with the heel of the lead foot resulted in the lowest moments and angles when compared with the other two ball positions.

Conclusions

The results indicate that positioning the ball in line with the heel of the lead foot is recommended to minimise the risk of injury to the lower limb joints during the hockey sweep pass. It is hoped that these findings will result in this position being implemented by players new to hockey or those returning to the sport following injury.

The Effect of Ankle Support on Lower Limb Kinematics During the Y-Balance Test Using Non-linear Dynamic Measures

Background: According to dynamical systems theory, an increase in movement variability leads to greater adaptability, which may be related to the number of feedforward and feedback mechanisms associated with movement and postural control. Using Higuchi dimension (HDf) to measure complexity of the signal and Singular Value Decomposition Entropy (SvdEn) to measure the number of attributes required to describe the biosignal, the purpose of this study was to determine the effect of kinesiology and strapping tape on center of pressure dynamics, myoelectric muscle activity, and joint angle during the Y balance test.

Method: Forty-one participants between 18 and 34 years of age completed five trials of the Y balance test without tape, with strapping tape (ST), and with kinesiology tape (KT) in a cross-sectional study. The mean and standard errors were calculated for the center of pressure, joint angles, and muscle activities with no tape, ST, and KT. The results were analyzed with a repeated measures ANOVA model (P_A < 0.05) fit and followed by Tukey post hoc analysis from the R package with probability set at P < 0.05.

Results: SvdEn indicated significantly decreased complexity in the anterior-posterior (p < 0.05) and internal-external rotation (p < 0.001) direction of the ankle, whilst HDf for both ST and KT identified a significant increase in ankle dynamics when compared to no tape (p < 0.0001) in the mediolateral direction. Taping also resulted in a significant difference in gastrocnemius muscle myoelectric muscle activity between ST and KT (p = 0.047).

Conclusion: Complexity of ankle joint dynamics increased in the sagittal plane of movement with no significant changes in the possible number of physiological attributes. In contrast, the number of possible physiological attributes contributing to ankle movement was significantly lower in the frontal and transverse planes. Simply adhering tape to the skin is sufficient to influence neurological control and adaptability of movement. In addition, adaptation of ankle joint dynamics to retain postural stability during a Y Balance test is achieved differently depending on the direction of movement.

Real-time gait event detection in a real-world environment using a laser-ranging sensor and gyroscope fusion method

OBJECTIVE

Wearable gait event detection (GED) techniques have great potential for clinical applications by aiding the rehabilitation of individuals in their daily living environment. Unlike previous wearable GED techniques, which have been proposed for offline detection or laboratory settings, we aimed to develop a real-time GED system adapted for utilization in the daily living environment.

APPROACH

This study presents a novel GED system in which foot clearance and sagittal angular velocity were incorporated to realize real-time GED in a real-world environment. The accuracy and robustness of the proposed system were validated in a real-world scenario that consisted of complex ground surfaces, i.e. varying inclinations. Forty-three subjects (23-83 years) were included in this study, and a total of 8866 gait cycles were recorded for analysis.

MAIN RESULTS

The proposed system demonstrated consistently high performance in detecting toe off (TO) and heel strike (HS) events in indoor and outdoor walking data which was supported by high performance scores. The detection accuracy of the walking data reached 2.59  ±  13.26 ms (indoor) and 3.31  ±  14.78 ms (outdoor) for TO events, 3.36  ±  15.92 ms (indoor) and 3.77  ±  16.99 ms (outdoor) for HS events. The proposed system showed better performance in detection precision than state-of-the-art real-time GED methods.

SIGNIFICANCE

The proposed system will benefit the development of long-term analysis and intervention techniques for use in clinics and daily living environments.

Coalitions of the Tarsal Bones

Tarsal coalitions are the result of impaired mesenchymal separation of the tarsal bones. The most common types include calcaneonavicular or talocalcaneal coalitions. Subtalar stiffness results in pathologic kinematics with increased risk of ankle sprains, planovalgus foot deformity, and progressive joint degeneration. Resection of the coalition yields good results. Tissue interposition may reduce the risk of reossification, and concomitant deformity should be addressed in the same surgical setting.

Pressure Distribution in the Ankle and Subtalar Joint With Routine and Oversized Foot Orthoses

BACKGROUND

Foot orthoses are used to treat many disorders that affect the lower limb. These assistive devices have the potential to alter the forces, load distribution, and orientation within various joints in the foot and ankle. This study attempts to quantify the effects of orthoses on the intra-articular force distribution of the ankle and subtalar joint using a cadaveric testing jig to simulate weight bearing.

METHODS

Five lower-limb cadaveric specimens were placed on a custom jig, where a 334-N (75-lb) load was applied at the femoral head, and the foot was supported against a plate to simulate double-leg stance. Pressure-mapping sensors were inserted into the ankle and subtalar joint. Mean pressure, peak pressure, contact area, and center of force were measured in both the ankle and subtalar joints for barefoot and 2 medial foot orthosis conditions. The 2 orthosis conditions were performed using (1) a 1.5-cm-height wedge to simulate normal orthoses and (2) a 3-cm-height wedge to simulate oversized orthoses.

RESULTS

The contact area experienced in the subtalar joint significantly decreased during 3-cm orthotic posting of the medial arch, but neither orthosis had a significant effect on the spatial mean pressure or peak pressure experienced in either joint.

CONCLUSION

The use of an oversized orthosis could lead to a decrease in the contact area and alterations in the distribution of pressure within the subtalar joint.

CLINICAL RELEVANCE

The use of inappropriate orthoses could negatively impact the force distribution in the lower limb.

Effects of different medial arch support heights on rearfoot kinematics

Background

Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait.

Methods

Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05).

Results

Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high.

Conclusion

Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait.

The effect of ankle posture on the load pathway through the hindfoot

The foot–ankle complex is frequently injured in a wide array of debilitating events such as car crashes. Numerical models and experimental tests have been used to assess injury risk, but most do not account for the variations in ankle posture that frequently occur during these events. In this study, the positions of the bones of the foot–ankle complex (particularly, the hindfoot) were quantified over a range of postures. Computed tomography scans were taken of a male cadaveric leg under axial loading with the ankle in five postures in which fractures are commonly reported. The difference in the location of the talus and calcaneus between the neutral and each repositioned posture was quantified, and substantial rotations and displacements were observed for all postures tested (talus: 3°–21.5°, 1.5–10.5 mm; calcaneus: 10°–20°, 1.5–24.5 mm). Strains were also recorded at six locations on bones of the ankle during testing and were found to be highest in the calcaneus during inversion-external rotation and highest in the talus during eversion-external rotation. Postural changes likely affect the load pathway of the foot–ankle complex, potentially altering the stress and strain fields from that of the neutral case and changing the location of fracture. This highlights the need for injury-predicting studies examining the effect of these positional changes and to develop revised injury criteria accounting for the most vulnerable conditions.

Validity of an ankle joint motion and position sense measurement system and its application in healthy subjects and patients with ankle sprain

BACKGROUND AND OBJECTIVE

Ankle motion and proprioception in multiple axis movements are crucial for daily activities. However, few studies have developed and used a multiple axis system for measuring ankle motion and proprioception. This study was designed to validate a novel ankle haptic interface system that measures the ankle range of motion (ROM) and joint position sense in multiple plane movements, investigating the proprioception deficits during joint position sense tasks for patients with ankle instability.

METHODS

Eleven healthy adults (mean ± standard deviation; age, 24.7 ± 1.9 years) and thirteen patients with ankle instability were recruited in this study. All subjects were asked to perform tests to evaluate the validity of the ankle ROM measurements and underwent tests for validating the joint position sense measurements conducted during multiple axis movements of the ankle joint. Pearson correlation was used for validating the angular position measurements obtained using the developed system; the independent t test was used to investigate the differences in joint position sense task performance for people with or without ankle instability.

RESULTS

The ROM measurements of the device were linearly correlated with the criterion standards (r = 0.99). The ankle instability and healthy groups were significantly different in direction, absolute, and variable errors of plantar flexion, dorsiflexion, inversion, and eversion (p < 0.05).

CONCLUSIONS

The results demonstrate that the novel ankle joint motion and position sense measurement system is valid and can be used for measuring the ankle ROM and joint position sense in multiple planes and indicate proprioception deficits for people with ankle instability.

Mechanical Impedance of the Non-loaded Lower Leg with Relaxed Muscles in the Transverse Plane

This paper describes the protocols and results of the experiments for the estimation of the mechanical impedance of the humans' lower leg in the External-Internal direction in the transverse plane under non-load bearing condition and with relaxed muscles. The objectives of the estimation of the lower leg's mechanical impedance are to facilitate the design of passive and active prostheses with mechanical characteristics similar to the humans' lower leg, and to define a reference that can be compared to the values from the patients suffering from spasticity. The experiments were performed with 10 unimpaired male subjects using a lower extremity rehabilitation robot (Anklebot, Interactive Motion Technologies, Inc.) capable of applying torque perturbations to the foot. The subjects were in a seated position, and the Anklebot recorded the applied torques and the resulting angular movement of the lower leg. In this configuration, the recorded dynamics are due mainly to the rotations of the ankle's talocrural and the subtalar joints, and any contribution of the tibiofibular joints and knee joint. The dynamic mechanical impedance of the lower leg was estimated in the frequency domain with an average coherence of 0.92 within the frequency range of 0-30 Hz, showing a linear correlation between the displacement and the torques within this frequency range under the conditions of the experiment. The mean magnitude of the stiffness of the lower leg (the impedance magnitude averaged in the range of 0-1 Hz) was determined as 4.9 ± 0.74 Nm/rad. The direct estimation of the quasi-static stiffness of the lower leg results in the mean value of 5.8 ± 0.81 Nm/rad. An analysis of variance shows that the estimated values for the stiffness from the two experiments are not statistically different.

The in vitro reliability of the CODA MPX30 as the basis for a method of assessing the in vivo motion of the subtalar joint

BACKGROUND

The considerable variation in subtalar joint structure and function shown by studies indicates the importance of developing a noninvasive in vivo technique for assessing subtalar joint movement. This article reports the in vitro testing of the CODA MPX30, an active infrared marker motion analysis system. This work represents the first stage in the development of a noninvasive in vivo method for measuring subtalar joint motion during walking.

METHODS

The in vitro repeatability of the CODA MPX30 system's measurements of marker position, simple and intermarker set angles, was tested. Angular orientations of markers representing the position of the talus and the calcaneus were measured using a purpose-designed marker placement model.

RESULTS

Marker location measurements were shown to vary by less than 1.0 mm in all of the planes. The measurement of a 90° angle was also found to be repeatable in all of the planes, although measurements made in the yz plane were shown to be consistently inaccurate (mean, 92.47°). Estimation of segmental orientation was found to be repeatable. Estimations of marker set orientations were shown to increase in variability after a coordinate transform was performed (maximum SD, 1.14°).

CONCLUSIONS

The CODA MPX30 was shown to produce repeatable estimations of marker position. Levels of variation in segmental orientation estimates were shown to increase subsequent to coordinate transforms. The combination of the CODA MPX30 and an appropriate marker placement model offers the basis of an in vivo measurement strategy of subtalar joint movement, an important development in the understanding of the function of the joint during gait.

Effects of balance training on gait parameters in patients with chronic ankle instability: a randomized controlled trial

OBJECTIVE

To examine the effects of a four-week balance training programme on ankle kinematics during walking and jogging in those with chronic ankle instability. A secondary objective was to evaluate the effect of balance training on the mechanical properties of the lateral ligaments in those with chronic ankle instability.

DESIGN

Randomized controlled trial.

SETTING

Laboratory.

SUBJECTS/PATIENTS

Twenty-nine participants (12 males, 17 females) with self-reported chronic ankle instability were randomly assigned to a balance training group or a control group.

INTERVENTION

Four weeks of supervised rehabilitation that emphasized dynamic balance stabilization in single-limb stance. The control group received no intervention.

MAIN OUTCOME MEASURES

Kinematic measures of rearfoot inversion/eversion, shank rotation, and the coupling relationship between these two segments throughout the gait cycle during walking and jogging on a treadmill. Instrumented ankle arthrometer measures were taken to assess anterior drawer and inversion talar tilt laxity and stiffness.

RESULTS

No significant alterations in the inversion/eversion or shank rotation kinematics were found during walking and jogging after balance training. There was, however, a significant decrease in the shank/rearfoot coupling variability during walking as measured by deviation phase after balance training (balance training posttest: 13.1 degrees +/- 6.2 degrees , balance training pretest: 16.2 degrees +/- 3.3 degrees , P = 0.03), indicating improved shank/rearfoot coupling stability. The control group did not significantly change. (posttest: 16.30 degrees +/- 4.4 degrees , pretest: 18.6 degrees +/- 7.1 degrees , P40.05) There were no significant changes in laxity measures for either group.

CONCLUSIONS

Balance training significantly altered the relationship between shank rotation and rearfoot inversion/eversion in those with chronic ankle instability.

Biomechanics and clinical analysis of the adult acquired flatfoot

The adult acquired flatfoot is a deformity that results from the loss of dynamic and static supportive structures of the medial longitudinal arch. The severity of the deformity is dependent upon the role of ligamentous disruption on the hindfoot that can be determined by careful clinical examination. Treatment of the adult flatfoot requires an understanding of the biomechanical effects of deforming forces, tendon dysfunction, ligament disruption, and joint sublaxation.

In vivo talocrural and subtalar kinematics: a non-invasive 3D dynamic MRI study

BACKGROUND

To improve diagnostic accuracy, prevent injury, and reduce the effect of impairments on hindfoot function, an understanding of the combined in vivo kinematics of the talocrural and subtalar joints is critical. Therefore, the purpose of this study was to test the feasibility of quantifying talocrural and subtalar joint kinematics using fast-phase contrast (fast-PC) MRI, a noninvasive, in-vivo technique for the study of three-dimensional joint motion.

METHODS

Nine normal ankles and two ankles with a Stieda process were studied. Subjects were each placed supine in a 1.5 T MRI and asked to maintain a repeated dorsiflexion-plantarflexion movement while a full sagittal-oblique fast-PC dataset was acquired. The orientation and position of the calcaneus, talus, and tibia were individually quantified from these data.

RESULTS

The precision and accuracy of tracking calcaneal, talar, and tibial movement was excellent. The three-dimensional subtalar kinematics demonstrated that the talus and calcaneus do not move as a single unit. Most calcaneal-tibial supination occurred at the talocrural joint. The ankles with a Stieda process had markedly different kinematics from each other as well as from the normal group.

CONCLUSIONS

This study demonstrated that fast-PC MRI is a viable, precise, and accurate technique for studying hindfoot kinematics and is potentially a useful clinical diagnostic tool. The findings call into question the earlier anatomical studies on which much of clinical practice on the foot and ankle is based. Since a clear link was found between anatomical variation and altered rearfoot kinematics, future study is warranted.

Mechanics of the subtalar joint and its function during walking

Knowledge of the location of the subtalar joint axis in individual patients would permit clinical assessment of the forces and moments that produce frontal-plane foot and ankle deformities. Biomechanical analysis of the subtalar joint is hindered, however, by the inaccessibility of the talus, which makes locating the joint axis difficult, and by the high degree of intersubject anatomic variation. This article discusses work done with cadaver specimens and using invasive methods in vivo that has enhanced our understanding of the mechanics of the subtalar joint and its function during gait. Also reviewed are investigations of the actions of muscles that cross the subtalar joint.

Ankle and subtalar kinematics measured with intracortical pins during the stance phase of walking

BACKGROUND

The absence of external landmarks on the talus has rendered the description of ankle and subtalar joint kinematics difficult. Abnormal motion at these joints has, however, been implied in the etiology of an array of lower extremity overuse injuries.

METHODS

Intracortical pins were inserted under local anesthesia in the tibia, talus, and calcaneus with external marker clusters traced by a video motion analysis system. Kinematic data were collected during walking trials on a flat surface for three subjects. Gait pattern was monitored by comparison of ground reaction force curves during stance phase with and without the pins inserted.

RESULTS

Results were presented in terms of helical axis orientation for both joints and the component rotations about these axes. Large intersubject differences were seen in both ankle and subtalar joint helical axis orientation. Maximum rotations over the complete stance phase for the ankle and subtalar joints respectively were: eversion/inversion, 6.3 degrees and 8.3 degrees; dorsiflexion/plantarflexion, 18.7 degrees and 3.7 degrees; and abduction/adduction, 5.0 degrees and 6.1 degrees.

CONCLUSIONS

The majority of ankle eversion/inversion occurred at the subtalar joint; however, the ankle component cannot be ignored. Abduction/adduction range of motion at the subtalar joint was surprisingly high, indicating that this component motion during walking is not purely attributable to the ankle joint. Future research should include greater subject numbers in order to present more universally applicable results.

CLINICAL RELEVANCE

The in vivo kinematics of the talus during weightbearing activity are poorly understood. The description of this motion may assist in the structuring of clinical rehabilitation and in the design and insertion of ankle joint prostheses.