Effects of additional weight-bearing on the in vivo kinematics of the human ankle joint complex during walking

Studies focusing on the kinematics of the ankle joint complex (AJC) have long been a key area of interest for biomechanists and orthopedic surgeons. However, it is not clear how additional weight-bearing walking affects the motion of the AJC compared to walking with a normal body weight (BW) or what adjustments the AJC would instinctively make to accommodate the additional load. To address this gap in knowledge, advanced dynamic biplane radiography combined with a model-based 2D-3D tracking technique was employed to elucidate the inherent kinematics of the AJC during the stance phase while walking with and without additional weight-bearing. It was found that walking with additional 50% body weight (BW + 50%) resulted in a greater dispersion of instantaneous axes of rotation in the talocrural and subtalar joints during the stance phase of gait. The talocrural joint is more plantarflexed and anteriorly translated during the early and late stance phases than during the midstance phases, which suggests that additional weight-bearing affects the stability of the AJC. Moreover, walking with BW + 50% showed that the center of rotation of the talocrural joint was positioned more superiorly and posteriorly during the foot flat to heel-off phase. This, accordingly, increases the ankle-foot gear ratio and the force of the dorsiflexors.

Effects of fatigue on the in vivo kinematics and kinetics of talocrural and subtalar joint during landing

Objective: Fatigue can affect the ankle kinematic characteristics of landing movements. Traditional marker-based motion capture techniques have difficulty in accurately obtaining the kinematics of the talocrural and subtalar joints. This study aimed to investigate the effects of fatigue on the talocrural and subtalar joints during the landing using dual fluoroscopic imaging system (DFIS). Methods: This study included fourteen healthy participants. The foot of each participant was scanned using magnetic resonance imaging to create 3D models. High-speed DFIS was used to capture images of the ankle joint during participants performing a single-leg landing jump from a height of 40 cm. Fatigue was induced by running and fluoroscopic images were captured before and after fatigue. Kinematic data were obtained by 3D/2D registration in virtual environment software. The joint kinematics in six degrees of freedom and range of motion (ROM) were compared between the unfatigued and fatigued conditions. Results: During landing, after the initial contact with the ground, the main movement of the talocrural joint is extension and abduction, while the subtalar joint mainly performs extension, eversion, and abduction. Compared to unfatigued, during fatigue the maximum medial translation (1.35 ± 0.45 mm vs. 1.86 ± 0.69 mm, p = 0.032) and medial-lateral ROM (3.19 ± 0.60 mm vs. 3.89 ± 0.96 mm, p = 0.029) of the talocrural joint significantly increased, the maximum flexion angle (0.83 ± 1.24° vs. 2.11 ± 1.80°, p = 0.037) of the subtalar joint significantly increased, and the flexion-extension ROM (6.17 ± 2.21° vs. 7.97 ± 2.52°, p = 0.043) of the subtalar joint significantly increased. Conclusion: This study contributes to the quantitative understanding of the normal function of the talocrural and subtalar joints during high-demand activities. During landing, the main movement of the talocrural joint is extension and abduction, while the subtalar joint mainly performs extension, eversion, and abduction. Under fatigue conditions, the partial ROM of the talocrural and subtalar joints increases.

The Within-Subjects Effects of Practice on Performance of Drop Landing in Healthy, Young Adults

Most studies of high-speed lower body movements include practice repetitions for facilitating consistency between the trials. We investigated whether 20 repetitions of drop landing (from a 30.5-cm platform onto a force plate) could improve consistency in maximum ground reaction force, linear lower body stiffness, depth of landing, and jump height in 20 healthy, young adults. Coefficient of variation was the construct for variability used to compare the first to the last five repetitions for each variable. We found that the practice had the greatest effect on maximum ground reaction force (p = .017), and had smaller and similar effects on lower body stiffness and depth of landing (p values = .074 and .044, respectively), and no measurable effect on jump height. These findings suggest that the effect of practice on drop landing differs depending upon the variable measure and that 20 repetitions significantly improve consistency in ground reaction force.

In vivo kinematic study of the tarsal joints complex based on fluoroscopic 3D-2D registration technique

The tarsal bones articulate with each other and demonstrate complicated kinematic characteristics. The in vivo motions of these tarsal joints during normal gait are still unclear. Seven healthy subjects were recruited and fourteen feet in total were tested in the current study. Three dimensional models of the tarsal bones were first created using CT scanning. Corresponding local 3D coordinate systems of each tarsal bone was subsequently established for 6DOF motion decompositions. The fluoroscopy system captured the lateral fluoroscopic images of the targeted tarsal region whilst the subject was walking. Seven key pose images during the stance phase were selected and 3D to 2D bone model registrations were performed on each image to determine joint positions. The 6DOF motions of each tarsal joint during gait were then obtained by connecting these positions together. The TNJ (talo-navicular joint) exhibited the largest ROMs (range of motion) on all rotational directions with 7.39±2.75°of dorsi/plantarflexion, 21.12±4.68°of inversion/eversion, and 16.11±4.44°of internal/external rotation. From heel strike to midstance, the TNJ, STJ (subtalar joint), and CCJ (calcaneao-cuboid joint) were associated with 5.97°, 5.04°, and 3.93°of dorsiflexion; 15.46°, 8.21°, and 5.82°of eversion; and 9.75°, 7.6°, and 4.99°of external rotation, respectively. Likewise, from midstance to heel off, the TNJ, STJ, and CCJ were associated with 6.39, 6.19°, and 4.47°of plantarflexion; 18.57°, 11.86°, and 6.32°of inversion and 13.95°, 9.66°, and 7.58°of internal rotation, respectively. In conclusion, among the tarsal joints, the TNJ exhibited the greatest rotational mobility. Synchronous and homodromous rotational motions were detected for TNJ, STJ, and CCJ during the stance phase.

Force-displacement differences in the lower extremities of young healthy adults between drop jumps and drop landings

We measured ground reaction force and lower extremity shortening in ten healthy, young adults in order to compare five trials of drop jumps to drop landings. Our dependent variable was the percentage of displacement (shortening) between the markers on the ASIS and second metatarsal heads on each LE, relative to the maximum shortening (100% displacement) for that trial at the point of greatest ground reaction force. We defined this as "percent displacement at maximum force" (%dFmax). The sample mean %dFmax was 0.73%±0.14% for the drop jumps, and 0.47%±0.09% for the drop landings. The mean within-subject difference score was 0.26%±0.20%. Two-tailed paired t test comparing %dFmax between the drop jump and drop landing yielded P=0.002. For all participants in this study, the %dFmax was greater in drop jumps than in drop landings. This indicates that in drop jumps, the point of maximum force and of maximum shortening was nearly simultaneous, compared to drop landings, where the point of maximum shortening followed that of maximum force by a greater proportion. This difference in force to displacement behavior is explained by linear spring behavior in drop jumps, and linear damping behavior in drop landings.

The impact of high-heeled shoes on ankle complex during walking in young women-In vivo kinematic study based on 3D to 2D registration technique

OBJECTIVE

To explore the accurate in vivo kinematic changes in the ankle complex when wearing low- and high-heel shoes (LHS and HHS, respectively).

MATERIALS AND METHODS

Twelve young women were tested unilaterally. Three-dimensional models of the tibia, talus, and calcaneus were first created based on CT scan results. The subjects walked at a self-controlled speed in barefoot, LHS (4cm), and HHS (10cm) conditions. A fluoroscopy system captured the lateral fluoroscopic images of the ankle complex. The images of seven key positions in the stance phase were selected, and 3D to 2D bone model registrations were performed to determine the joint positions. The mean of 6 degree of freedom (DOF) range of motions (ROM), joint positions, and angular displacements of the ankle complex during the gait were then obtained.

RESULTS

For the talocrural joint, the rotational ROMs of the subjects either in LHS or HHS condition displayed no significant difference from those in barefoot condition. For the subtalar joint, all the rotational ROMs in the HHS condition and the internal/external rotations in the LHS condition significantly decreased compared with those in the barefoot condition. The talocrural joint was positioned significantly more plantarflexed, inverted, internally rotated, and posteriorly seated in all seven poses in HHS condition, compared with those in barefoot condition.

CONCLUSION

HHS mainly affected the rotational motion of the ankle complex during walking. The talocrural joint position was abnormal, and the subtalar joint ROM decreased during the gait in HHS condition. Only a few kinematic changes occurred in LHS condition relative to the barefoot condition.

Three-dimensional motions of distal syndesmosis during walking

Introduction

The motion of the distal syndesmosis correlates highly with the instability, while an accurate kinematic description of the distal tibiofibular joint during normal gait has not previously been presented.

Material and methods

Sixteen healthy syndesmoses of sixteen living subjects (8 male and 8 female) were studied during stance phase of the normal gait. Data of CT scanning were collected first and used to create the 3D models of the distal tibia and fibula. The lateral X-ray images of the syndesmosis were captured by fluoroscopy when the subject was walking. Seven key-pose images were selected for subsequent 3D to 2D bone model registration and six degrees-of-freedom (DOF) motions of syndesmosis were then calculated. A validation experiment was also conducted to confirm the accuracy of the 3D/2D technique for the syndesmosis.

Results

During the stance phase, the distal tibiofibular joint exhibited with 2.98 ± 1.10° of dorsi/plantarflexion, 5.94 ± 1.52° of inversion/eversion, and 5.99 ± 2.00° of internal/external rotation; 2.63 ± 1.05 mm on medial/lateral, 3.86 ± 1.65 mm on anterior/posterior, and 4.12 ± 1.53 mm on superior/inferior translation. From heel strike to mid-stance, the syndesmosis demonstrated 1.69° of dorsiflexion, 3.61° of eversion, and 3.95° of external rotation. Likewise, from mid-stance to heel-off, the syndesmosis presented 1.04° of plantarflexion, 4.95° of inversion, and 5.13° of internal rotation.

Conclusion

During the stance phase of normal gait, internal/external rotation and vertical motion play dominant roles in terms of rotation and translation, respectively.

Direct assessment of 3D foot bone kinematics using biplanar X-ray fluoroscopy and an automatic model registration method

BACKGROUND

Quantifying detailed 3-dimensional (3D) kinematics of the foot in contact with the ground during locomotion is crucial for understanding the biomechanical functions of the complex musculoskeletal structure of the foot. Biplanar X-ray fluoroscopic systems and model-based registration techniques have recently been employed to capture and visualise 3D foot bone movements in vivo, but such techniques have generally been performed manually. In the present study, we developed an automatic model-registration method with biplanar fluoroscopy for accurate measurement of 3D movements of the skeletal foot.

METHODS

Three-dimensional surface models of foot bones were generated prior to motion measurement based on computed tomography. The bone models generated were then registered to biplanar fluoroscopic images in a frame-by-frame manner using an optimisation technique, to maximise similarity measures between occluding contours of the bone surface models with edge-enhanced fluoroscopic images, while avoiding mutual penetration of bones. A template-matching method was also introduced to estimate the amount of bone translation and rotation prior to automatic registration.

RESULTS

We analysed 3D skeletal movements of a cadaver foot mobilized by a robotic gait simulator. The 3D kinematics of the calcaneus, talus, navicular and cuboid in the stance phase of the gait were successfully reconstructed and quantified using the proposed model-registration method. The accuracy of bone registration was evaluated as 0.27 ± 0.19 mm and 0.24 ± 0.19° (mean ± standard deviation) in translation and rotation, respectively, under static conditions, and 0.36 ± 0.19 mm and 0.42 ± 0.30° in translation and rotation, respectively, under dynamic conditions.

CONCLUSIONS

The measurement was confirmed to be sufficiently accurate for actual analysis of foot kinematics. The proposed method may serve as an effective tool for understanding the biomechanical function of the human foot during locomotion.

Changes in talocrural and subtalar joint kinematics of barefoot versus shod forefoot landing

Background

Synergetic talocrural and subtalar joint movements allow adaptation to different footwear and/or surface conditions. Therefore, knowledge of kinematic differences between barefoot and shod conditions is valuable for the study of adaptations to footwear conditions. The objective of this study was to assess the kinematic differences in the talocrural and subtalar joints during barefoot and shod landing.

Methods

Seven healthy participants (4 males and 3 females) participated in a landing trial under barefoot and shod conditions. Fluoroscopic images and forceplate data were collected simultaneously to calculate the talocrural and subtalar joint kinematics and the vertical ground reaction force.

Results

Upon toe contact, the plantarflexion angle of the talocrural joint during the barefoot condition was significantly larger than that during the shod condition (barefoot, 20.5 ± 7.1°, shod, 17.9 ± 8.3°, p =0.03). From toe contact to heel contact, the angular changes at the talocrural and subtalar joint were not significantly different between the barefoot and shod conditions; however, the changes in the subtalar eversion angles in the barefoot condition, from heel contact to 150 ms after toe contact, were significantly larger than those in the shod condition.

Conclusions

These results suggest that footwear was able to reduce the eversion angle of the subtalar joint after heel contact during landing; the effect of wearing footwear was quite limited. Therefore, induced rearfoot kinematic alterations to prevent or manage injuries by neutral-type footwear are likely to be impractical.