Gait Analysis to Monitor Fracture Healing of the Lower Leg

New Parameters Based on Ground Reaction Forces for Monitoring Rehabilitation Following Tibial Fractures and Assessment of Heavily Altered Gait

Instrumented insoles have created opportunities for patient monitoring via long-term recordings of ground reaction forces (GRFs). As the GRF curve is altered in patients after lower-extremity fracture, parameters defined on established curve landmarks often cannot be used to monitor the early rehabilitation process. We aimed to screen several new GRF curve-based parameters for suitability and hypothesized an interrelation with days after surgery. In an observational longitudinal study, data were collected from 13 patients with tibial fractures during straight walking at hospital visits using instrumented insoles. Parametrized curves were fitted and regression analyses conducted to determine the best fit, reflected in the highest R2-value and lowest fitting error. A Wald Test with t-distribution was employed for statistical analysis. Strides were classified as regular or non-regular, and changes in this proportion were analyzed. Among the 12 parameters analyzed, those with the highest R2-values were the mean force between inflection points (R2 = 0.715, p < 0.001, t42 = 9.89), the absolute time between inflection points (R2 = 0.707, p < 0.001, t42 = 9.83), and the highest overall force (R2 = 0.722, p < 0.001, t42 = 10.05). There was a significant increase in regular strides on both injured (R2 = 0.427, p < 0.001, t42 = 5.83) and healthy (R2 = 0.506, p < 0.001, t42 = 6.89) sides. The proposed parameters and assessment of the regular stride ratio enable new options for analyses and monitoring during rehabilitation after tibial shaft fractures. They are robust to pathologic GRF curves, can be determined independently from spatiotemporal coherence, and thus might provide advantages over established methods.

Methods to quantify gait rehabilitation following lower limb fractures

Lower limb fragility fractures require long-term rehabilitation and are also very expensive to treat. Clinically, early weight bearing and walking stability were reported as key measures of fracture restoration. This study introduces methods to numerically quantify these performance indices for a range of ankle and knee joint fractures. As a follow-up of initial treatment, experimental data was collected using force plates from 367 subjects divided into seven groups: ankle fracture (AF), lower leg ankle fracture (AL), calcaneus foot fracture (CF), knee tibia fracture (KF), knee patella fracture (KP), kneecap rupture (KR), and normal limb (NL). For each joint, data was analysed to evaluate intralimb and interlimb weight-bearing and walking stability for all fracture conditions. These thresholds were statistically compared with normal subjects. Some advantages of evaluating fracture restoration indices over the others include:•to quantify fracture restoration (weight-bearing, walking stability, and gait symmetry) using minimum setup and signal requirements.•to provide comprehensive tools to assess and overcome fracture-associated complications through a detailed preview of fractured limb functionality during subphases of a gait cycle.•in clinical research, such assessments are important as a reference to evaluate existing or new rehabilitative interventions.

The walking surface influences vertical ground reaction force and centre of pressure data obtained with pressure-sensing insoles

Background

Gait can be continuously monitored via vertical ground reaction force (VGRF) and centre of pressure (COP) measurement with pressure-sensing insoles. During daily living, a variety of walking surfaces will be encountered, which could affect the collected data. These effects might need to be taken into account when analysing disease- or injury-related gait characteristics to prevent misinterpretation, especially when drawing conclusions from data obtained in clinical populations. We hypothesized characteristic changes in insole-derived VGRF and COP parameters of healthy participants when walking on different surfaces.

Methods

Participants walked on flat indoor surface, flat and inclined outdoor surfaces, as well as on forest, gravel, grass, and sand surfaces while wearing pressure-sensing insoles with 16 pressure sensors each at a recording frequency of 100 Hz. Several gait parameters were extracted from the VGRF and COP data, and were compared between surfaces using repeated measures ANOVA.

Results

Thirty participants were included (22 women and 7 men, age 30 ± 12 years, height 172 ± 8 cm, weight 76 ± 23 kg). VGRF and COP data were significantly influenced by the type of surface. The rmANOVA revealed significant within-subject differences between the walking surfaces in all calculated parameters. The largest changes in the VGRF and COP patterns occurred during uphill and downhill walking. Walking on compliant surfaces led to increased gait variability. The highest variability was observed when walking on sand. The change from walking indoors to outdoors, be it on flat, inclined, forest, gravel, grass or sand surfaces, was characterized by a characteristic change in the VGRF stance-phase curve. Based on these characteristic changes, it could be possible to identify whether someone is walking on a slope, as well as on non-compliant or compliant surfaces, while it is difficult to distinguish between different types of compliant surfaces.

Conclusion

VGRF data are affected by the type of walking surface in healthy adults. Walking on a slope affects VGRF and COP parameters, and in addition, the compliance of the surface increases their variability. When analysing gait data measured via insoles during daily living, we recommend to correct for the surface type to decrease variability.

Longitudinal weight and plantar pressure distribution while standing after tibial or malleolar fractures in patients with or without fracture union

Fracture healing is usually monitored by clinical impressions and radiographs. Objective and easy methods for assessing fracture healing without radiation would be beneficial. The aim of this study was to analyse whether weight and plantar pressure while standing can be used to monitor healing of tibial or malleolar fractures and whether these parameters can discriminate between patients with and without union. Thirteen patients were longitudinally assessed during each postoperative clinical visit, of whom two developed a nonunion. Eleven matched healthy controls were assessed once. Additionally, five patients already experiencing nonunion were assessed once at the time of their nonunion diagnosis. All participants performed a standing task for ten seconds with pressure-sensing insoles. Greatest improvements were detected throughout the first three months in patients with union. However, six months after surgery, more than half of the parameters were still significantly different from those of the controls. The weight and pressure distributions did not differ between patients with or without union six months after surgery. A standing task can be used to monitor improvements in weight and pressure distribution throughout the healing process of tibial or malleolar fractures, but lacks potential to discriminate between patients with or without fracture union.

The predictive value of stress-induced hyperglycemia parameters for delayed healing after tibial fracture post-surgery

PURPOSE

The objective of this retrospective cohort study was to investigate the predictive value of stress-induced hyperglycemia parameters for delayed healing after tibial fracture post-surgery.

METHODS

A cohort of 108 participants who underwent surgical intervention for tibial fractures caused by trauma was included in this retrospective study. Data collected from electronic medical records encompassed demographic characteristics, bone healing assessments, stress-induced hyperglycemia parameters, inflammatory markers, and stress-related hormones. Comparative analyses, correlation analyses, univariate logistic regression analyses, and receiver operating characteristic (ROC) curve analyses were conducted to assess the predictive value of the studied parameters.

RESULTS

The delayed healing group exhibited higher levels of fasting blood glucose, postprandial glucose, and HbA1c, as well as elevated levels of inflammatory markers and stress-related hormones compared to the normal healing group. Correlation analysis and logistic regression demonstrated positive associations between stress-induced hyperglycemia parameters, inflammatory markers, stress-related hormones, and delayed union of tibial fractures (R2: 0.183 ~ 0.403;OR: 1.091 ~ 16.332). ROC curve analysis revealed high area under the curve (AUC = 0.911) values for stress-induced hyperglycemia parameters, indicating their potential as predictive markers for delayed healing. Multivariate regression analysis further substantiated the predictive capability of stress-induced hyperglycemia parameters.

CONCLUSION

The study findings highlight the complex interplay between stress-induced hyperglycemia, inflammatory response, and bone healing outcomes in patients undergoing surgical intervention for tibial fractures. The identification of stress-induced hyperglycemia parameters as potential predictive markers for delayed healing after tibial fracture surgery offers insights for risk assessment and patient management, emphasizing the need for comprehensive understanding of these factors to optimize postoperative recovery in orthopedic patients.

Advanced Engineering Technology in Orthopedic Research

Musculoskeletal injuries are increasing in conjunction with the aging of populations and the rising frequency of exercise [...].

Predicting the Healing of Lower Extremity Fractures Using Wearable Ground Reaction Force Sensors and Machine Learning

Lower extremity fractures pose challenges due to prolonged healing times and limited assessment methods. Integrating wearable sensors with machine learning can help overcome these challenges by providing objective assessment and predicting fracture healing. In this retrospective study, data from a gait monitoring insole on 25 patients with closed lower extremity fractures were analyzed. Continuous underfoot loading data were processed to isolate steps, extract metrics, and feed them into three white-box machine learning models. Decision tree and Lasso regression aided feature selection, while a logistic regression classifier predicted days until fracture healing within a 30-day range. Evaluations via 10-fold cross-validation and leave-one-out validation yielded stable metrics, with the model achieving a mean accuracy, precision, recall, and F1-score of approximately 76%. Feature selection revealed the importance of underfoot loading distribution patterns, particularly on the medial surface. Our research facilitates data-driven decisions, enabling early complication detection, potentially shortening recovery times, and offering accurate rehabilitation timeline predictions.

A Biomechanical Comparison Study of Plate-Nail and Dual-Plate Fixation in AO/OTA 41-C2 Tibial Plateau Fractures

BACKGROUND CONTEXT

This study's purpose was to evaluate the biomechanical performance of plate-nail and dual-plate fixation for the treatment of AO/OTA 41-C2 tibial plateau fractures.

METHODS

Twenty synthetic tibias were selected and randomly divided into a plate-nail group (n = 10) and a dual-plate group (n = 10). After the artificial tibias were osteotomized to simulate AO/OTA 41-C2 tibial plateau fractures in both groups, the plate-nail and the dual-plate methods, respectively, were used for fixation, and then axial compression loading, three-point bending, torsion, and axial failure tests were carried out. The data of each group were recorded and statistically analyzed.

RESULTS

In the axial compression test, the average stiffness of the plate-nail group was higher than that of the dual-plate group (p < 0.05). The displacement generated in the plate-nail group was significantly smaller than that in the dual-plate group (p < 0.05). In the resisting varus test, the stress of the plate-nail group was significantly higher than that of the dual-plate group (p < 0.05). In the resisting valgus test, the stress of the plate-nail group was slightly higher than that of the dual-plate group, but the difference was not statistically significant (p > 0.05). In the static torsion test, the load applied to the plate-nail group was smaller than that of the dual-plate group when rotated to 5° (p < 0.05). In the axial compression failure test, the average ultimate load of the plate-nail group was significantly higher than that of the dual-plate group (p < 0.05).

CONCLUSION

The treatment of AO/OTA 41-C2 tibial plateau fractures with plate-nail fixation is superior to that with dual-plate fixation in resisting axial stress and preventing tibial varus deformity, while dual-plate fixation has better resisting torsional ability.

Gait dynamic stability evaluation in patients undergoing hip joint fractures - tools to measure rehabilitation effectiveness

A hip joint fracture includes a break in the thigh (femur) or coxa bone near the pelvis. During fracture healing, stability and weight bearing by the affected limb are key indicators to measure patients' improvement. Conventionally, the rehabilitation effectiveness is monitored through clinical examinations, patients' feedback, and few studies also reported instrumented gait evaluations. A gap remains there to numerically quantify the recovery in patients' stability and weight bearing in response to rehabilitation therapies. This study introduces Nyquist and Bode (N&B) methods to analyse the instrumented gait signals further and evaluate gait stability in hip fracture patients during weight loading and unloading transitions. The centre of pressure (CoP) data was recorded using force plates for conditions: coxa hip fracture (HC), femur hip fracture (HF), and normal hip joint (NH). The time rate of CoP signals illustrated two major impulses during the loading and unloading phases which were modelled in time and frequency domains. The frequency models were further analysed by applying N&B methods and stability margins were computed for both impaired and healthy conditions. Results illustrated a significant decrease (Kruskal-Wallis's test, p < 0.001) in the intralimb walking stability of both fracture conditions. Further, Spearman's correlation between CoP velocities of fractured and intact limbs illustrated significant interlimb dependencies to maintain walking stability (p < 0.001) during weight loading and unloading transitions. Overall, the HF impairment illustrated the least intralimb walking stability and relatively greater interlimb dependencies. Clinically, these methods and findings are important to measure the recovery in patients undergoing rehabilitation after a hip joint or other lower limb impairments.

Methods to accelerate fracture healing - a narrative review from a clinical perspective

Bone regeneration is a complex pathophysiological process determined by molecular, cellular, and biomechanical factors, including immune cells and growth factors. Fracture healing usually takes several weeks to months, during which patients are frequently immobilized and unable to work. As immobilization is associated with negative health and socioeconomic effects, it would be desirable if fracture healing could be accelerated and the healing time shortened. However, interventions for this purpose are not yet part of current clinical treatment guidelines, and there has never been a comprehensive review specifically on this topic. Therefore, this narrative review provides an overview of the available clinical evidence on methods that accelerate fracture healing, with a focus on clinical applicability in healthy patients without bone disease. The most promising methods identified are the application of axial micromovement, electromagnetic stimulation with electromagnetic fields and direct electric currents, as well as the administration of growth factors and parathyroid hormone. Some interventions have been shown to reduce the healing time by up to 20 to 30%, potentially equivalent to several weeks. As a combination of methods could decrease the healing time even further than one method alone, especially if their mechanisms of action differ, clinical studies in human patients are needed to assess the individual and combined effects on healing progress. Studies are also necessary to determine the ideal settings for the interventions, i.e., optimal frequencies, intensities, and exposure times throughout the separate healing phases. More clinical research is also desirable to create an evidence base for clinical guidelines. To make it easier to conduct these investigations, the development of new methods that allow better quantification of fracture-healing progress and speed in human patients is needed.

Characteristic Changes of the Stance-Phase Plantar Pressure Curve When Walking Uphill and Downhill: Cross-Sectional Study

BACKGROUND

Monitoring of gait patterns by insoles is popular to study behavior and activity in the daily life of people and throughout the rehabilitation process of patients. Live data analyses may improve personalized prevention and treatment regimens, as well as rehabilitation. The M-shaped plantar pressure curve during the stance phase is mainly defined by the loading and unloading slope, 2 maxima, 1 minimum, as well as the force during defined periods. When monitoring gait continuously, walking uphill or downhill could affect this curve in characteristic ways.

OBJECTIVE

For walking on a slope, typical changes in the stance phase curve measured by insoles were hypothesized.

METHODS

In total, 40 healthy participants of both sexes were fitted with individually calibrated insoles with 16 pressure sensors each and a recording frequency of 100 Hz. Participants walked on a treadmill at 4 km/h for 1 minute in each of the following slopes: -20%, -15%, -10%, -5%, 0%, 5%, 10%, 15%, and 20%. Raw data were exported for analyses. A custom-developed data platform was used for data processing and parameter calculation, including step detection, data transformation, and normalization for time by natural cubic spline interpolation and force (proportion of body weight). To identify the time-axis positions of the desired maxima and minimum among the available extremum candidates in each step, a Gaussian filter was applied (σ=3, kernel size 7). Inconclusive extremum candidates were further processed by screening for time plausibility, maximum or minimum pool filtering, and monotony. Several parameters that describe the curve trajectory were computed for each step. The normal distribution of data was tested by the Kolmogorov-Smirnov and Shapiro-Wilk tests.

RESULTS

Data were normally distributed. An analysis of variance with the gait parameters as dependent and slope as independent variables revealed significant changes related to the slope for the following parameters of the stance phase curve: the mean force during loading and unloading, the 2 maxima and the minimum, as well as the loading and unloading slope (all P<.001). A simultaneous increase in the loading slope, the first maximum and the mean loading force combined with a decrease in the mean unloading force, the second maximum, and the unloading slope is characteristic for downhill walking. The opposite represents uphill walking. The minimum had its peak at horizontal walking and values dropped when walking uphill and downhill alike. It is therefore not a suitable parameter to distinguish between uphill and downhill walking.

CONCLUSIONS

While patient-related factors, such as anthropometrics, injury, or disease shape the stance phase curve on a longer-term scale, walking on slopes leads to temporary and characteristic short-term changes in the curve trajectory.

Recent Advances in Wearable Healthcare Devices: From Material to Application

In recent years, the proliferation of wearable healthcare devices has marked a revolutionary shift in the personal health monitoring and management paradigm. These devices, ranging from fitness trackers to advanced biosensors, have not only made healthcare more accessible, but have also transformed the way individuals engage with their health data. By continuously monitoring health signs, from physical-based to biochemical-based such as heart rate and blood glucose levels, wearable technology offers insights into human health, enabling a proactive rather than a reactive approach to healthcare. This shift towards personalized health monitoring empowers individuals with the knowledge and tools to make informed decisions about their lifestyle and medical care, potentially leading to the earlier detection of health issues and more tailored treatment plans. This review presents the fabrication methods of flexible wearable healthcare devices and their applications in medical care. The potential challenges and future prospectives are also discussed.

Long-term continuous instrumented insole-based gait analyses in daily life have advantages over longitudinal gait analyses in the lab to monitor healing of tibial fractures

Introduction: Monitoring changes in gait during rehabilitation allows early detection of complications. Laboratory-based gait analyses proved valuable for longitudinal monitoring of lower leg fracture healing. However, continuous gait data recorded in the daily life may be superior due to a higher temporal resolution and differences in behavior. In this study, ground reaction force-based gait data of instrumented insoles from longitudinal intermittent laboratory assessments were compared to monitoring in daily life. Methods: Straight walking data of patients were collected during clinical visits and in between those visits the instrumented insoles recorded all stepping activities of the patients during daily life. Results: Out of 16 patients, due to technical and compliance issues, only six delivered sufficient datasets of about 12 weeks. Stance duration was longer (p = 0.004) and gait was more asymmetric during daily life (asymmetry of maximal force p < 0.001, loading slope p = 0.001, unloading slope p < 0.001, stance duration p < 0.001). Discussion: The differences between the laboratory assessments and the daily-life monitoring could be caused by a different and more diverse behavior during daily life. The daily life gait parameters significantly improved over time with union. One of the patients developed an infected non-union and showed worsening of force-related gait parameters, which was earlier detectable in the continuous daily life gait data compared to the lab data. Therefore, continuous gait monitoring in the daily life has potential to detect healing problems early on. Continuous monitoring with instrumented insoles has advantages once technical and compliance problems are solved.

Gait analysis: An effective tool to mechanically monitor the bone regeneration of critical-sized defects in tissue engineering applications

INTRODUCTION

Tissue engineering has emerged as an innovative approach to treat critical-size bone defects using biocompatible scaffolds, thus avoiding complex distraction surgeries or limited stock grafts. Continuous regeneration monitoring is essential in critical-size cases due to the frequent appearance of non-unions. This work evaluates the potential clinical use of gait analysis for the mechanical assessment of a tissue engineering regeneration as an alternative to the traditional and hardly conclusive manual or radiological follow-up.

MATERIALS AND METHODS

The 15-mm metatarsal fragment of eight female merino sheep was surgically replaced by a bioceramic scaffold stabilized with an external fixator. Gait tests were performed weekly by making the sheep walk on an instrumented gangway. The evolution of different kinematic and dynamic parameters was analyzed for all the animal's limbs, as well as asymmetries between limbs. Finally, potential correlation in the recovery of the gait parameters was evaluated through the linear regression models.

RESULTS

After surgery, the operated limb has an altered way of carrying body weight while walking. Its loading capacity was significantly reduced as the stance phases were shorter and less impulsive. The non-operated limbs compensated for this mobility deficit. All parameters were normalizing during the consolidation phase while the bone callus was simultaneously mineralizing. The results also showed high levels of asymmetry between the operated limb and its contralateral, which exceeded 150% when analyzing the impulse after surgery. Gait recovery significantly correlated between symmetrical limbs.

CONCLUSIONS

Gait analysis was presented as an effective, low-cost tool capable of mechanically predicting the regeneration of critical-size defects treated by tissue engineering, as comparing regeneration processes or novel scaffolds. Despite the progressive normalization as the callus mineralized, the bearing capacity reduction and the asymmetry of the operated limb were more significant than in other orthopedic alternatives.