Objective To provide the objective basis for the evaluation of the operative results of vascularized greater trochanter bone flap in treating osteonecrosis of the femoral head (ONFH) by three-dimensional gait analysis. Methods Between March 2006 and March 2007, 35 patients with ONFH were treated with vascularized greater trochanter bone flap, and gait analysis was made by using three-dimensional gait analysis system before operation and at 1, 2 years afteroperation. There were 23 males and 12 females, aged 21-52 years (mean, 35.2 years), including 8 cases of steroid-induced, 7 cases of traumatic, 6 cases of alcohol ic, and 14 cases of idiopathic ONFH. The left side was involved in 15 cases, and right side in 20 cases. According to Association Research Circulation Osseous (ARCO) classification, all patients were diagnosed as having femoral-head necrosis at stage III. Preoperative Harris hip functional score (HHS) was 56.2 ± 5.6. The disease duration was 1.5-18.6 years (mean, 5.2 years). Results All incisions healed at stage I without early postoperative compl ications of deep vein thrombosis and infections of incision. Thirty-five patients were followed up 2-3 years with an average of 2.5 years. At 2 years after operation, the HHS score was 85.8 ± 4.1, showing significant difference when compared with the preoperative score (t=23.200, P=0.000). Before operation, patients showed a hip muscles gait, short gait, reduce pain gait, and the pathological gaits significantly improved at 1 year after operation. At 1 year and 2 years after operation, step frequency, pace, step length and hip flexion, hip extension, knee flexion, ankle flexion were significantly improved (P lt; 0.01). Acceleration-time curves showed that negative wave and spinous wave at acceleration-stance phase of front feet and hind feet in affected l imb were obviously reduced at 1 year and 2 years after operation. Postoperative petronas wave appeared at swing phase; the preoperative situation was three normal phase waves. Conclusion These results suggest that three-dimensional gait analysis before and after vascularized greater trochanter for ONFH can evaluate precisely hip vitodynamics variation.
Gait recognition is a new technology in biometric recognition and medical treatment which has advantages such as long-distance and non-invasiveness. Depending on the differences between different people's walking postures, we can recognize individuals by characteristics extracted from the images of walking movement. A complete gait recognition process usually includes gait sequence acquisition, gait detection, feature extracting and recognition. In this paper, the commonly used methods of these four processes are introduced, and feature extraction methods are classified from different multi-angle views. And then the new algorithm of multi-view emerged in recent years is highlighted. In addition, this paper summarizes the existing difficulties of gait recognition, and looks into the future development trends of it.
When people are walking, they will produce gait signals and different people will produce different gait signals. The research of the gait signal complexity is really of great significance for medicine. By calculating people's gait signal complexity, we can assess a person's health status and thus timely detect and diagnose diseases. In this study, the Jensen-Shannon divergence (JSD), the method of complexity analysis, was used to calculate the complexity of gait signal in the healthy elderly, healthy young people and patients with Parkinson's disease. Then we detected the experimental data by variance detection. The results showed that the difference among the complexity of the three gait signals was great. Through this research, we have got gait signal complexity range of patients with Parkinson's disease, the healthy elderly and healthy young people, respectively, which would provide an important basis for clinical diagnosis.
Based on force sensing resistor(FSR) sensor, we designed insoles for pressure measurement, which were stable and reliable with a simple structure, and easy to wear and to do outdoor experiments with. So the insoles could be used for gait detection system. The hardware includes plantar pressure sensor array, signal conditioning unit and main circuit unit. The software has the function of data acquisition, signal processing, feature extraction and classification function. We collected 27 groups of gait data of a healthy person based on this system to analyze the data and study pressure distribution under various gait features, i.e. walking on the flat ground, uphill, downhill, up the stairs, and down the stairs. These five gait patterns for pattern recognition and classification by K-nearest neighbors (KNN) recognition algorithm reached up to 90% accuracy. This preliminarily verified the usefulness of the system.
The first metatarsophalangeal joint bending plays an important role in the foot movement. However, the existing researches mainly focused on the movement scope of the joint and the clinical treatments of related foot diseases. In order to investigate the effects of the first metatarsophalangeal joint bending on human walking gait stability, the present researchers recruited 6 healthy young men to perform the first metatarsophalangeal joint constraint (FM-JC) and barefoot (BF) walking tests. Data of the temporal and spatial parameters, the joint angles of lower limbs, the ground reaction forces (GRF) and utilized coefficients of friction (UCOF) were collected and analyzed. The results showed that, since hip and knee could produce compensation motions, the FMJC had no significant effects on waking gait, but the slip and fall probability increased significantly.
Nowadays, for gait instability phenomenon, many researches have been carried out at home and abroad. However, the relationship between plantar pressure and gait parameters in the process of balance adjustment is still unclear. This study describes the human body adaptive balance reaction during slip events on slippery level walk by plantar pressure and gait analysis. Ten healthy male subjects walked on a level path wearing shoes with two contrastive contaminants (dry, oil). The study collected and analyzed the change rule of spatiotemporal parameters, plantar pressure parameters, vertical ground reaction force (VGRF), etc. The results showed that the human body adaptive balance reaction during slip events on slippery level walk mainly included lighter touch at the heel strikes, tighter grip at the toe offs, a lower velocity, a shorter stride length and longer support time. These changes are used to maintain or recover body balance. These results would be able to explore new ideas and provide reference value for slip injury prevention, walking rehabilitation training design, research and development of walking assistive equipments, etc.
Aiming at the gait instability phenomenon under disturbed conditions, domestic and foreign scholars have done some research works, but the relationship between the independent balancing act with the surface electromyographic and gait parameters in the process of instability has yet rarely been involved. In this study, using the gait analysis combined with electromyographic signal analysis, we investigated balance adjustment mechanism of joints and muscles of the human lower limb under the condition of walking on the level trail and after foot heel touching the ground and unexpected sliding. Studying 10 healthy subjects with the unified shoes, we acquired and analyzed the changing rule of the lower limb joint torque, joint angle, and the surface electromyographic of the main muscle groups involved in situations of dry or oid trails. Studies showed that when accident sliding happened, the body would increase ankle dorsiflexion torque moment, knee unbend torque and straight angle, and meanwhile increase the torque of hip extension, and timely adjust muscle activation time (Followed by activation of Tibialis anterior muscle→Rectus femoris→Gastrocnemius→Femoral biceps) to adjust the center of gravity, to maintain balance of the body, and to avoid falling down. The results of the research could be used to explore new ideas and to provide a certain reference value for preventing slip damage, rehabilitation training and development of lower limb walker.
Turning gait is very common in daily lives. However, study of turning is still limited. For researching the differences of the walking characteristics between straight gait and turning gait and between different turning strategies, and for analyzing the endopathic factor, this study selected 10 healthy young men to perform straight walking and 90° turning using two turning strategies (outside leg turning and inside leg turning). The Vicon capture system and plantar pressure capture system were used to measure gait parameters and plantar pressure parameters at the same time. The study showed that stride velocity reduced while stride time and proportion of stance time increased when turning was compared to straight walking. Inside leg turning strategy needed stronger muscle controlling and could promote turning, while outside leg turning strategy was more stable. This results will offer data for projecting gait of biped robot and provide reference value for walking rehabilitation training design and development of walking assistive equipments, etc.
The purpose of this study is to determine how restricting inversion-eversion and pronation-supination motions of the ankle joint complex influences the stability of human gait. The experiment was carried out on a slippery level ground walkway. Spatiotemporal gait parameter, kinematics and kinetics data as well as utilized coefficient of friction (UCOF) were compared between two conditions, i.e. with restriction of the ankle joint complex inversion-eversion and pronation-supination motions (FIXED) and without restriction (FREE). The results showed that FIXED could lead to a significant increase in velocity and stride length and an obvious decrease in double support time. Furthermore, FIXED might affect the motion angle range of knee joint and ankle joint in the sagittal plane. In FIXED condition, UCOF was significantly increased, which could lead to an increase of slip probability and a decrease of gait stability. Hence, in the design of a walker, bipedal robot or prosthetic, the structure design which is used to achieve the ankle joint complex inversion-eversion and pronation-supination motions should be implemented.
This study aims to establish a multi-segment foot model which can be applied in dynamic gait simulation. The effectiveness and practicability of this model were verified afterwards by comparing simulation results with those of previous researches. Based on a novel hybrid dynamic gait simulator, bone models were imported into automatic dynamic analysis of mechanical systems (ADAMS). Then, they were combined with ligaments, fascia, muscle and plantar soft tissue that were developed in ADMAS. Multi-segment foot model was consisted of these parts. Experimental data of human gait along with muscle forces and tendon forces from literature were used to drive the model and perform gait simulation. Ground reaction forces and joints revolution angles obtained after simulation were compared with those of previous researches to validate this model. It showed that the model developed in this paper could be used in the dynamic gait simulation and would be able to be applied in the further research.