Biomechanical comparison of two surgical methods for Hallux Valgus deformity: Exploring the use of artificial neural networks as a decision-making tool for orthopedists.

Hallux Valgus foot deformity affects gait performance. Common treatment options include distal oblique metatarsal osteotomy and chevron osteotomy. Nonetheless, the current process of selecting the appropriate osteotomy method poses potential biases and risks, due to its reliance on subjective human judgment and interpretation. The inherent variability among clinicians, the potential influence of individual clinical experiences, or inherent measurement limitations may contribute to inconsistent evaluations. To address this, incorporating objective tools like neural networks, renowned for effective classification and decision-making support, holds promise in identifying optimal surgical approaches. The objective of this cross-sectional study was twofold. Firstly, it aimed to investigate the feasibility of classifying patients based on the type of surgery. Secondly, it sought to explore the development of a decision-making tool to assist orthopedists in selecting the optimal surgical approach. To achieve this, gait parameters of twenty-three women with moderate to severe Hallux Valgus were analyzed. These patients underwent either distal oblique metatarsal osteotomy or chevron osteotomy. The parameters exhibiting differences in preoperative and postoperative values were identified through various statistical tests such as normalization, Shapiro-Wilk, non-parametric Wilcoxon, Student t, and paired difference tests. Two artificial neural networks were constructed for patient classification based on the type of surgery and to simulate an optimal surgery type considering postoperative walking speed. The results of the analysis demonstrated a strong correlation between surgery type and postoperative gait parameters, with the first neural network achieving a remarkable 100% accuracy in classification. Additionally, cases were identified where there was a mismatch with the surgeon's decision. Our findings highlight the potential of artificial neural networks as a complementary tool for surgeons in making informed decisions. Addressing the study's limitations, future research may investigate a wider range of orthopedic procedures, examine additional gait parameters and use more diverse and extensive datasets to enhance statistical robustness.

Do commonly used postoperative orthopaedic shoes help off-load the forefoot?

PURPOSE: The aim of the experiment presented in this study was to determine the pressure distribution within the forefoot depending on the type of orthopaedic footwear used. METHODS: The study included 27 women aged 20 to 25. The Zebris FDM-2 dynamographic platform was used in foot pressure measurements. The load distribution was measured in three types of orthopaedic footwear: MedSurg, MedSurgPro and OrthoWedge. The full gait cycle was recorded. The Cavanagh masks were applied to the load distribution results processed into a graphic form. The data were analysed using Statistica v.13.1. RESULTS: In the forefoot area, i.e. the metatarsal bones and toes 1-5, the lowest loads were reported in the shoes that off-load the forefoot (0.2 N/cm², p < 0.001). In the area of the first to fifth metatarsal bones and the hallux, the highest load was observed in the rocker shoe, accounting for 19.7 N/cm² ( p < 0.001). For comparison, high pressure in the flat shoe was found in the area of toes 2 to 5 ( p < 0.001). CONCLUSIONS: In the area of the metatarsal and toe bones, the pressure exerted was highest in the commonly used rocker shoe. The flat shoe provides an even and uniform load in all areas of the forefoot, while this type of shoe does not significantly reduce the pressure forces on the forefoot. The shoe that was the most effective in off-loading was the forefoot off-loading shoe (OrthoWedge). Barefoot walking puts less load on the forefoot compared to the flat and rocker shoes used after orthopaedic procedures.

Neck and Trunk Muscle Strength in Children With Spinal Muscular Atrophy Is Lower Than in Healthy Controls and Depends on Disease Type.

Background: Neck and trunk muscle strength and relationship with motor function in individuals with spinal muscular atrophy (SMA) is not investigated well. Information on maximum muscle strength that children with SMA may develop considerably expands the possibilities of assessing the effectiveness of pharmacological treatment methods and therapeutic procedures. This study sought to assess neck and trunk muscle strength in patients with SMA and to compare it with values noted in healthy children. Methods: The study involved 56 individuals with SMA aged 5-16 not treated pharmacologically, including 9 patients with SMA type 1 (SMA1), 27 with SMA type 2 (SMA2), and 20 with SMA type 3 (SMA3). The control group included 111 healthy individuals aged 5-16. Neck and trunk muscle strength was assessed by means of a maximum voluntary isometric contraction method with the use of a handheld digital muscle tester MICROFET2. Moreover, relative strength was also calculated by standardising the maximum voluntary isometric contraction according to body mass. The Kruskal-Wallis test, Mann-Whitney U-test, and Spearman's rank correlation were used for statistical analysis. Results: The reliability of the neck and trunk muscle strength measurements with the handheld digital muscle tester was excellent with ICC > 0.9. The values of muscle strength in SMA groups were significantly lower than in the control group. The values of relative torque of the neck muscles expressed in percentage values calculated with regard to the control group were at the level of 47.6-51.6% in SMA1 group, 54.8-58.1% in SMA2 group and 80.6-90.3% in SMA3 group. The percentage values for upper and lower trunk muscle strength were at the level of 42.6-68.4% in SMA1 group, 56.9-75.4% in SMA2 group and 76.7-94.8% in SMA3 group. Conclusion: Handheld dynamometry provides reliable measures of neck and trunk muscle strength in SMA children. Neck and trunk muscle strength in children with SMA is lower than in healthy controls and depends on disease type, which confirms the theory based on clinical observations. Further, study is needed to investigate the effect of pharmacological treatment on the strength of the neck/trunk muscles, and relationship between neck and trunk muscle strength and motor capabilities.

Muscle Force Patterns in Lower Extremity Muscles for Elite Discus Throwers, Javelin Throwers and Shot-Putters - A Case Study.

Optimal release variables, as well as the kinematics and kinetics of athletes, are crucial for the maximization of throwing distance in athletics. Mathematical models and simulations allow throwing techniques to be studied. However, muscle force patterns and the contribution of specific muscle groups in athletics throwing events are not well understood and require detailed research. In this study, important variables of the muscle force generated during the javelin, discus and shot put events were determined using OpenSim software. Musculoskeletal simulations were carried out based on kinematic and kinetic data collected using the Vicon system and Kistler plates with the help of nine top Polish athletes (three in each event). OpenSim software was used to calculate muscle forces and joint velocities. For each discipline, it was found that the main muscle groups involved in the throwing movement were better at distinguishing throwers than joint velocities. The contribution of right ankle plantar flexors at the beginning of the final acceleration phase as well as left hip extensors at the end of the final acceleration phase was given special attention. This work provides a better understanding of the techniques used in athletics throws. Musculoskeletal simulations of throwing styles might help coaches analyze the techniques of individual athletes, resulting in better adjustment of training programmes and injury prevention protocols.

Mechanical energy flows between body segments in ballistic track-and-field movements (shot put, discus, javelin) as a performance evaluation method.

PURPOSE: Seeking a method to evaluate and monitor the performance of the shot put, discus and javelin throw, we analyzed the transfer of mechanical energy between body segments. METHODS: The study was conducted on groups consisting of elite throwers on the Polish National Team for each of the aforementioned sport disciplines. The movements of each throw were recorded using Vicon system and Kistler plates. The power and energy fluctuations were computed for the final acceleration phase of each throw. RESULTS: In all three disciplines studied, we found an average energy loss of 1.63 J/kg generated from shoulder to wrist. The value of generated energy from ankle to torso initially increased in all disciplines, followed by a descent - with the exception of the javelin throw, where there was an average 27% decrease in both hip joints. We found strong correlations between relative amplitude values of energy and the athlete's personal performance records: -0.8226 (shot put), 0.6008 (discus) and 0.7273 (javelin). CONCLUSIONS: Measuring the transfer of mechanical energy between body segments offers a useful method for evaluating the technique of ballistic movements and for monitoring training progress.

Assessing Gait Stability before and after Cochlear Implantation.

BACKGROUND: It is known that cochlear implantation may alter the inner ear and induce vestibular disorders. RESEARCH QUESTION: How does cochlear implantation influence gait stability? Material and Methods. An experimental group of twenty-one subjects scheduled for cochlear implantation underwent gait testing twice, on the day before cochlear implantation (BCI) and three months after cochlear implantation (ACI), using a motion capture system. A control group of 30 age-matched healthy individuals were also tested. RESULTS: In the experimental group, the gait stability ratio (GSR) was found to improve in 17 subjects after implantation, by an average of 6%. Certain other parameters also showed statistically significant improvement between the two experimental group tests: step time (p<0.001), single-support phase walking speed (p<0.05), and center of mass (CoM) (p<0.05). Using the CoM results of the control group, we devised a stability classification system and applied it to the pre- and postimplantation subjects. After implantation, increases were seen in the number of subjects classified in interval II (strong stability) and III (weak stability). The number of subjects in interval I (perfect stability) decreased by 1 and in interval IV (no stability) by 4. SIGNIFICANCE: (1) Although cochlear implantation intervenes in the vestibular area, we found evidence that gait stability improves in most subjects after the surgery, reducing the risk of falls. (2) We found statistically significant improvements in individual parameters (such as single-support phase time), in GSR, and in CoM. (3) Based on CoM results, we proposed a new rule-of-thumb way of classifying patients into gait stability intervals, for use in rehabilitation planning and monitoring.

Compensatory strategy for ankle dorsiflexion muscle weakness during gait in patients with drop-foot.

BACKGROUND: Pathological movement patterns are characterized by abnormal kinematics, kinetics and muscle activations that alter the distribution of muscle forces during walking. AIM: The objective of this study was to identify what compensatory strategy is evident in muscle force distribution in patients with drop-foot, in response to weakness in the dorsiflexor muscles. METHODS: A sample of 10 patients with drop-foot were evaluated by a computerized gait analysis system and compared to a group of 10 healthy subjects. Muscle-actuated simulations of normal and drop-foot walking were performed using OpenSim software. A musculoskeletal model with 43 muscles acting on one lower extremity was used in order to perform the simulations. In order to evaluate the difference between muscle force curves in the healthy and the drop-foot populations, an integrals of each muscle curve were computed. RESULTS: The group of patients with drop-foot exhibited an increased force integral for all muscle groups, except for the ankle evertors. The highest increases were observed for hip adductors (112%), hip extensors (88%), knee and hip flexors (83% and 50%, respectively) and for the plantarflexor (47%). These results were mainly influenced by the following muscles: flexor digitorum and hallucius, tibialis posterior and semitendinosus. The force integral for these muscles increased by more than 200% in the drop-foot group as compared to the control group. In addition, significant changes (>100%) were noted for the posterior thigh muscle group (semitendinosus, biceps femoris long and short head), which are responsible for bending the knee joint and straightening the hip joint. CONCLUSIONS: It was proved that the loss in muscle force in individual muscle groups of the ankle joint are compensated for by the increased force and activity in other muscles acting on this joint and another muscles in neighbouring joints. The results may have important implications for physiotherapy treatments.

Artificial neural network simulation of lower limb joint angles in normal and impaired human gait.

PURPOSE: Simulating the complexities of lower limb motion can be useful for orthosis or rehabilitation planning. The aim of this study was to develop an artificial neural network (ANN) able to accurately simulate the changes in the angle of the ankle, knee and hip joints during the gait cycle, then to use it to simulate the impact of a restricted range of ankle and hip joint angle changes on the progres- sion of the knee joint angle. METHODS: Thirty four young healthy students participated in the study. Gait kinematics data were collected using the Vicon system, then analyzed with an ANN. RESULTS: We developed an ANN able to accurately simulate the progression of joint angles of lower-limb motion; its simulation of the impact of restricted ankle and hip joint angular ranges in the on the knee joint indicate that the braking phase is critical. CONCLUSIONS: ANNs offer a useful research method in clinical biomechanics. Further research in this vein should expand our understanding of compensatory functions in the lower limbs.

Types of falls and strategies for maintaining stability on an unstable surface.

BACKGROUND: Falls constitute an important health issue. They cause significant morbidity, mortality and have marked psychological effects on the individual, too. The aim of this study has been to determine parameters describing human movement strategies for balance and the reaction if balance is lost as a result of an unstable ground, and to attempt to describe the types of falls. MATERIAL AND METHODS: The study group comprised 20 volunteers. Kinematic parameters of falling and dynamic stability were measured using the Vicon Motion System and the Biodex Balance System SD. During the test, subjects stood for 20 s on the tilting platform. The analysis was conducted based on the first recordings, when the participants were not prepared for the event and their reactions were natural. A cluster analysis tool was applied to divide the behavior of people during the test. RESULTS: Based on motion range for kinematic parameters, the cluster analysis revealed 2 types of human behavior: falling (stepping) and restoring balance. Two types of falls were also observed: side and back falls. Moreover, on the basis of angular values for tilting plate, 4 zones were determined. The frequency of access to these zones by each joint revealed 3 strategies to maintain balance: ankle, knee and hip strategy. CONCLUSIONS: A set of initial conditions that may be used for future numerical simulations was also determined. Furthermore, the results presented in this study are likely to support the analysis of the effects and the falling patterns. Med Pr 2018;69(3):245-252.

Assessing the asymmetry of free gait in healthy young subjects.

PURPOSE: The purpose of this study was to derive reference values for a four-level scale intended to evaluate variation in free gait asymmetry measurements in healthy subjects. METHODS: This evaluation is based on kinetic values for the left and right lower limbs during gait, registered with advanced measurement systems and assessed using the symmetry index (SI) developed by Robinson. RESULTS: For the majority of parameters, the SI does not follow normal distribution. As such, quartile values were used to create intervals for a four-step scale of assessing symmetry of free gait in healthy subjects for each gait parameter of interest. The SI rating intervals were from 0% (very good symmetry) to 21.2% (very poor symmetry) for kinetic parameters. The poorest symmetry was observed for horizontal force F3. CONCLUSIONS: The four-step scale of assessing symmetry in free gait in healthy subjects can be used in diagnosing gait disorders, devising surgical treatment strategies, and monitoring the rehabilitation process. Reference values for intervals of symmetry indicators in healthy subjects can be used as criteria for comparing individuals with/without disabilities.

Inter-individual similarities and variations in muscle forces acting on the ankle joint during gait.

Muscle forces acting over the ankle joint play an important role in the forward progression of the body during gait. Yet despite the importance of ankle muscle forces, direct in-vivo measurements are neither possible nor practical. This makes musculoskeletal simulation useful as an indirect technique to quantify the muscle forces at work during locomotion. The purpose of this study was to: 1) identify the maximum peaks of individual ankle muscle forces during gait; 2) investigate the order over which the muscles are sorted based on their maximum peak force. Three-dimensional kinematics and ground reaction forces were measured during the gait of 10 healthy subjects, and the data so obtained were input into the musculoskeletal model distributed with the OpenSim software. In all 10 individuals we observed that the soleus muscle generated the greatest strength both in dynamic (1856.1N) and isometric (3549N) conditions, followed by the gastrocnemius in dynamic conditions (1232.5N). For all other muscles, however, the sequence looks different across subjects, so the k-means clustering method was used to obtain one main order over which the muscles' peak-forces are sorted. The results indicate a common theme, with some variations in the maximum peaks of ankle muscle force across subjects.

First signs of elderly gait for women.

BACKGROUND: The aims of this study have been twofold: to attempt to reduce the number of spatiotemporal parameters used for describing gait through the factor analysis and component analysis; and to explore the critical age of decline for other gait parameters for healthy women. MATERIAL AND METHODS: A total of 106 women (aged ≥ 40 years old (N = 76) and ≤ 31 years old (N = 30)) were evaluated using a pressure-sensitive mat (Zebris Medical System, Tübingen, Germany) for collecting spatiotemporal gait parameters. RESULTS: The factor analysis identified 2 factors - labelled Time and Rhythm - that accounted for 72% of the variation in significant free-gait parameters; the principal component analysis identified 4 of these parameters that permit full clinical evaluation of gait quality. No difference was found between the groups in terms of the values of parameters reflecting the temporal nature of gait (Rhythm), namely step time, stride time and cadence, whereas significant differences were found for total double support phase (p < 0.001). Next, seeking evidence of a critical decline in gait, we selected 3 parameters: total double support, stride time and velocity. We concluded that the women taking part in the experiment manifested significant signs of senile gait after the age of 60 years old, with the first symptoms thereof already manifesting themselves after 50 years of age. CONCLUSIONS: We show that among 26 spatiotemporal parameters that may be used for characterizing gait, at least a half of them may be omitted in the assessment of gait correctness; a finding that may be useful in clinical practice. The finding that the onset of senile gait occurs in the case of women after the age of 60 years old, in turn, may be useful in evaluating the ability for performing types of physical work that mainly require ambulation. Med Pr 2017;68(4):441-448.

Effect of Drop Foot on Spatiotemporal, Kinematic, and Kinetic Parameters during Gait.

Background. The complexity of the structure and function of a living body can be affected by disorders and can cause various dysfunctions. Objective. The aim of this study was to determine compensatory mechanisms in subjects with drop foot during gait. Methods. The study evaluated 10 subjects with drop foot (DF) whose results were compared to a group of 10 healthy controls (C). Spatiotemporal, kinematic, and kinetic parameters during the gait cycle were collected using Vicon system synchronized with Kistler platforms. Results. Spatiotemporal, kinematic, and kinetic parameters were significantly different between the analysed groups. In the DF group, the subjects walked almost 47% slower and performed 60% less steps per minute compared to the C group. The main problem in the DF group was insufficient ankle dorsiflexion in the 0-10% of the gait cycle. Mean values in the groups during the first 10% of the gait cycle were as follows: DF (-10.42 ± 5.7°) and C (-2.37 ± 1.47°), which affected the substantial differences in the values of muscle torque: DF (0.2 ± 0.1 Nm/kg) and C (-0.26 ± 0.06 Nm/kg). Conclusions. Comparative analysis for joint angles and torques demonstrated that the mechanism of compensation is the most noticeable in the knee joint and less in the hip joint.

Mechanisms of compensation in the gait of patients with drop foot.

BACKGROUND: Drop foot is a complex syndrome, with multiple interactions between joints and muscles. Abnormalities in movement patterns can be measured using motion capture techniques, but identifying compensation mechanisms remains challenging. METHODS: In order to identify compensatory mechanisms in patients with drop foot, this study evaluated a sample of 15 such patients using a computerized gait analysis system, as compared to a group of 15 healthy subjects. FINDINGS: Four classes of parameters were distinguished, falling in differing intervals of percentage differences between the groups in the study. The first class comprised two kinematic parameters for which the values of percentage differences in the control group were more than 100% greater than for the patient group. The second class comprised two kinetic parameters falling in the interval of 100-49%. In the third class, in the 49-20% interval the main differences were observed for spatiotemporal parameters, whereas in the 20-4% interval the differences were distributed similarly for kinematic, kinetic and spatiotemporal parameters. INTERPRETATION: These differences in gait pattern between the groups may be related to both primary motor deficits and secondary compensatory mechanisms. Generally, we conclude that drop foot affects the patients' overall kinematic and kinetic gait parameters, with compensation seen as a chain originating from a change of movement within the ankle joint.

Transfer of mechanical energy during the shot put.

The aim of this study was to analyse transfer of mechanical energy between body segments during the glide shot put. A group of eight elite throwers from the Polish National Team was analysed in the study. Motion analysis of each throw was recorded using an optoelectronic Vicon system composed of nine infrared camcorders and Kistler force plates. The power and energy were computed for the phase of final acceleration of the glide shot put. The data were normalized with respect to time using the algorithm of the fifth order spline and their values were interpolated with respect to the percentage of total time, assuming that the time of the final weight acceleration movement was different for each putter. Statistically significant transfer was found in the study group between the following segments: Right Knee - Right Hip (p = 0.0035), Left Hip - Torso (p = 0.0201), Torso - Right Shoulder (p = 0.0122) and Right Elbow - Right Wrist (p = 0.0001). Furthermore, the results of cluster analysis showed that the kinetic chain used during the final shot acceleration movement had two different models. Differences between the groups were revealed mainly in the energy generated by the hips and trunk.

The Impact of a Vestibular-Stimulating Exercise Regime on Postural Stability in People with Visual Impairment.

The aim of the study was to assess the impact of a vestibular-stimulating exercise regime on postural stability in individuals with visual impairment. The study group consisted of 70 people, including 28 persons (15 female and 13 male) with visual impairment and 42 (21 female and 21 male) without visual impairment. Each individual in the group with visual impairment was medically qualified for a 3-month training program. The research methodology included medical examination, anthropometric tests, and stabilometry tests on a Biodex Balance System SD (BBS). The tests were conducted twice: once before the start of training and again after 3 months of rehabilitation. The group with visual impairment showed significantly worse postural stability results than the control group for most of the stability parameters evaluated (OSI, APSI, and MLSI). Differences were noted between the groups with and without visual impairment for dynamic tests in women and for static tests in men. After training, the two groups showed roughly similar results for the stabilometry test with eyes closed. We conclude that exercises stimulating the vestibular system with head and body movements should be recommended for individuals with visual impairments to achieve better balance retention.

Laterality versus ankle dorsi- and plantarflexion maximal torques.

PURPOSE: The aim of the study was to analyze the connections between the functional asymmetries of lower limbs, taking into account morphological feet features, and ankle dorsi- and plantarflexion maximal torques in men and women. METHODS: The study population consisted of 56 young subjects among which there were 30 women and 26 men. The assessment of upper and lower limbs' side dominance was performed on the basis of surveys, verified with simple motor tasks that resembled the actions characteristic of the upper and lower limbs. The measurements of body build, as well as foot build, were performed with the use of accepted instruments according to the anthropometry standards. The measurements of longitudinal foot arches were conducted using the pantographic method. Ankle dorsi- and plantarflexion maximal torque values were measured under static conditions. RESULTS: We found a positive correlation between the functional dominance of lower limb and greater strength only for ankle plantarflexion maximal torque values in correct laterality variants in women and in only one variant in men. No correlation was found between foot morphological asymmetry and the ankle dorsi- and plantarflexion maximal torque values, either in women or in men. CONCLUSION: Our results support the idea that the functional lower limb dominance is not equivalent to the greater muscle strength.

Laterality versus jumping performance in men and women.

PURPOSE: The aim of this study was to investigate relationships between functional asymmetry of lower limbs, taking into account morphological features of the feet, and jumping ability in men and women. METHODS: The study population consisted of 56 subjects, 30 women (age: 20.29 ± 0.59 years; body mass: 58.13 ± 4.58 kg, body height: 165.60 ± 5.03 cm) and 26 men (age: 20.41 ± 0.78 years, body mass: 78.39 ± 8.42 kg, body height: 181.15 ± 6.52 cm). The measurements of longitudinal arches were performed with the plan- tographic method on the basis of Clarke's angle mapped on a computer foot print. The measurements of jumping performance during bilateral (two legs) and unilateral (single-leg) counter movement jump (CMJ) were done on force plate. All subjects jumped three times each type of jump (total 9 jumps): three right leg, three left leg and three two legs. We put the test results through a detailed statistical analysis with the Statistica 8.0. The t-test for dependent variables and the Wilcoxon signed-rank test for divergent variances of the fea- tures compared. The analysis of relationships between the chosen podometric and plantographic features and jumping performance was conducted on the basis of the Pearson product-moment correlation coefficient (for the features which presented normal distribution, according to the Shapiro-Wilk test). RESULTS: The correlations between values of height of single-leg jumps (right and left) and bilateral jumps, and foot indices were found in few cases only in men who had greater values of jump height with the non-dominant limb. We did not find a significant difference in jumping ability between the dominant limb and the non-dominant limb in women. We found bilateral deficits in jumping ability in the study groups, though we did not find significant differences (P ≤ 0.05) between the values for women (a mean of 6.5%) and for men (a mean of 8.4%). CONCLUSION: We found significant gender differences of the correlations between the values of height of jumps (single-leg and bilateral jumps) and foot indices.

The impact of a vestibular-stimulating exercise regimen on postural stability in women over 60.

BACKGROUND/OBJECTIVE: The aim of this study was to assess whether a program of exercise specifically designed to target the vestibular organ improved the postural stability of female participants over 60 years old. METHODS: Twenty-eight healthy female volunteers aged from 60 years to 76 years were assigned to a group (n = 15) engaging in vestibular-stimulating exercises, or to a control group (n = 13) engaging in traditional training exercises. Training sessions (∼45 minutes each) occurred twice a week over the course of 3 months. The following parameters were analyzed before and after training for both groups: stabilogram ellipse area and radii, total length of stabilogram, and visual-inspection indicator (eyes open). RESULTS: Results in terms of stabilogram ellipse area and radius without visual control (eyes closed) revealed statistically significant differences in the experimental group between the values before and after the training regimen (74.8 ± 51.6 - 54.5 ± 42.5 for area of ellipse, 6.6 ± 2.8 - 5.8 ± 2.8 for axis minor, 13.2 ± 4.3 - 11.1 ± 3.3 for axis major, respectively). No significant changes were observed in the control group. CONCLUSION: Exercises stimulating the vestibular organ, such as those described herein, should be a part of efforts to improve balance in older people.