Szczepan Piszczatowski

Purpose: Balance disorders increase fall risk in older adults, yet global gait parameters may lack sensitivity to detect subtle impairments. This study evaluates whether detailed spatiotemporal and plantar-pressure measures more effectively identify balance-related gait alterations. Methods: Fifty-two older adults (55–82 years) were assigned to a balance disorders group (n = 26) or a control group (n = 26) based on fall history and Dizziness Handicap Inventory scores. Barefoot walking trials were recorded using a pedobarographic platform. Scalar spatiotemporal gait parameters and pressure-related signals were normalized to body height and body mass, respectively. Dynamic foot balance parameters were analyzed as time-normalized waveforms over the stance phase. Between-group and within-group comparisons were performed using conventional statistical methods and Statistical Parametric Mapping (SPM). Results: No statistically significant between-group differences were found in global spatiotemporal gait parameters or in group-averaged mean and variability waveforms of dynamic foot balance measures. However, within-group SPM analyses presented stance-phase intervals with significant left–right asymmetries in selected dynamic foot balance parameters, occurring more frequently in participants with balance disorders. These asymmetries were parameter- as well as phase-specific and showed substantial inter-individual variability. Conclusions: Older adults with balance disorders may preserve overall gait characteristics during steady-state walking while exhibiting subtle, localized asymmetries in dynamic foot balance. Waveform-based plantar pressure analysis may capture balance-related gait alterations not detected by global gait measures, although the clinical relevance of these findings requires further investigation.

Background: The role of the periarticular muscles of the knee joint in ensuring body balance is still ambiguous. Therefore, we conducted clinical and biomechanical assessments on 52 older adults (36 women and 16 men, age of 67.58 ± 7.30 years, body weight of 75.10 ± 13.42 kg, and height of 163.92 ± 8.80 cm) to determine the role of the knee muscles in balance maintenance. Methods: The clinical examination included the Dizziness Handicap Inventory (DHI), the Geriatric Depression Scale (GDS), the Performance-Oriented Mobility Assessment (POMA), the Functional Reach Test (FRT), the Falls Efficacy Scale—International (FES-I), and bioimpedance parameters (skeletal muscle mass—SMM—and its derived parameter—Diff SMM). The biomechanical assessment involved parameters that characterize muscle torques of knee joint extensors and flexors in isokinetic and isometric conditions, as well as changes in the centre of pressure (COP) position while standing with eyes open and closed. Results: Based on treatment history and DHI results (>10 points), 26 participants were identified as having balance disorders, while the remaining participants formed the control group. Statistical analysis was performed to determine differences between the groups. The groups significantly differed in terms of the results obtained from the DHI (p < 0.001) and GDS (p = 0.04) questionnaires as well as FES-I (p < 0.001) and POMA (p = 0.002) tests. While SMM (p = 0.012) was similar in the groups, Diff SMM (p = 0.04) significantly differed. The multiple regression analysis confirmed the knee joint extensor parameters’ significant role in predicting the COP path (p = 0.03 and p = 0.04 for two assumed models). Conclusions: The obtained results proved that the muscle torques of knee extensors can be used in the diagnostic process of older patients with balance disorders, indicating possible rehabilitation directions.

Background: Multi-comminuted, intra-articular fractures of the distal humerus still pose a challenge to modern orthopedics due to unsatisfactory treatment results and a high percentage (over 50%) of postoperative complications. When surgical treatment is chosen, such fractures are fixed using two plates with locking screws, which can be used in three spatial configurations: either parallel or one of two perpendicular variants (posterolateral and posteromedial). The evaluation of the fracture healing conditions for these plate configurations is unambiguous. The contradictions between the conclusions of biomechanical studies and clinical observations were the motivation to undertake a more in-depth biomechanical analysis aiming to indicate the weak points of two-plate fracture stabilization. Methods: Research was conducted using the finite element method based on an experimentally validated model. Three variants of distal humerus fracture (Y, λ, and H) were fixed using three different plate configurations (parallel, posterolateral, and posteromedial), and they were analyzed under six loading conditions, covering the whole range of flexion in the elbow joint (0–145°). A joint reaction force equal to 150 N was assumed, which corresponds with holding a weight of 1 kg in the hand. The biomechanical conditions of bone union were assessed based on the interfragmentary movement (IFM) and using criteria formulated by Steiner et al. Results: The IFMs were established for particular regions of all of the analyzed types of fracture, with distinction to the normal and tangential components. In general, the tangential component of IFM was greater than normal. A strong influence of the elbow joint’s angular position on the IFM was observed, with excessive values occurring for flexion angles greater than 90°. In most cases, the smallest IFM values were obtained for the parallel plaiting, while the greatest values were obtained for the posteromedial plating. Based on IFM values, fracture healing conditions in particular cases (fracture type, plate configuration, loading condition, and fracture gap localization) were classified into one of four groups: optimal bone union (OPT), probable union (PU), probable non-union (PNU), and non-union (NU). Conclusions: No plating configuration is able to ensure distal humerus fracture union when the full elbow flexion is allowed while holding a weight of 1 kg in the hand. However, flexion in the range of 0–90° with such loadings is acceptable when using parallel plating, which is a positive finding in the context of the early rehabilitation process. In general, parallel plating ensures better conditions for fracture healing than perpendicular plate configurations, especially the posteromedial version.

Background: The aim of the study was to answer two questions: 1 – Can data processing algorithms ensure sufficient accuracy for estimating human body pose via wearable systems? 2 – How to process the IMU sensor data to obtain the most accurate information on the human body pose? To answer these questions, the authors evaluated proposed algorithms in terms of accuracy and reliability. Methodology: data acquisition was performed with tested IMU sensors system mounted onto a Biodex System device. Research included pendulum movement with seven angular velocities (10-120°/s) in five angular movement ranges (30-120°). Algorithms used data from accelerometers and gyroscopes and considered complementary and/or Kalman filters with adjusted parameters. Moreover, angular velocity registration quality was also taken into consideration. Results: differences between means for angular velocity were 0.55÷1.05°/s and 1.76÷3.11%. In the case of angular position relative error of means was 4.77÷10.84%, relative error of extreme values was 2.15÷4.81% and Spearman’s correlation coefficient was 0.74÷0.89. Conclusions: Algorithm calculating angles based on acceleration-derived quaternions and with implementation of Kalman filter was the most accurate for data processing and can be adapted for future work with IMU sensors systems, especially in wearable devices that are designated to support human in daily activity.

The mechanical approach to the structural bone-implant analysis by Finite Element Method (FEM) of the elastic - viscoelastic structures will be given in this paper. On the basis of the physical model of the bone-implant system taking into account non-homogeneous and viscoelastic bone material properties, quasi-static boundary value problem (QSBVP) describing the interactions between elastic and viscoelastic material coupled with the proper conditions on the area of contact will be formulated. The variational formulation, necessary to solve the problem will be also presented as an example of the applied approach to QSBVP. Some numerical results of strain, stress and energy density distributions will be shown in different points of the bone-implant system.

One of the most important elements in the process of designing bone - implant structures (in the case of the alloplastics of joints) is the selection of a stiffness for the implant stem which is appropriate to the surrounding bone tissue. This is critical under conditions of load transfer between implant and bone. The present work attempts to describe the influence of rheological changes in the mechanical properties of bone tissue when the implanted joint is under working conditions, with the assumption of purely elastic properties of the implant. Shown are the results of numerical analysis carried out on the finite elements method of the bone - implant system, taking into account the viscoelasticity and non-homogeneity of bone tissue.

The medical imaging and reconstruction program (TOMCOMP) which allows CAD/CAM systems and CT (Computerized Tomography) system integration is elaborated in the present work. The main TOMPCOMP program tasks are: data reading from CT with reconstruction and visualisation of the separate tomograms, external and internal shapes generation of the bone elements by the use of image processing methods and algorithms, determination of the xyz characteristic bone shape points coordinates and their export to the CAD/CAM systems. By the surfaces in the NURBS space technique appliance, the reconstructed bone modelling was made in the CAD system. The results of the application of the above described system are presented as an example of radial bone head identification by the CT used to examine the object in the Unigraphics system.

Purpose: The treatment of comminuted fractures of distal humerus poses a challenge for orthopaedics. Previous studies assessing the global stiffness of the bone - stabilizer system - made it impossible to explicitly indicate an optimal configuration of the locking plates in the treatment of this kind of fractures. The aim of the present research was to comparatively analyze the stabilization conditions of intraarticular fractures of distal humerus with the use of various configurations of the stabilizer. Methods: The research was based on the analysis of mutual displacements of bone fragments. Such evaluation was performed with the use of numerical simulation conducted with the use of the finite element method. A realistic model of humerus was based on the CT data. Three spatial configurations of the stabilizer (parallel, posteromedial and posterolateral) were considered. The mutual displacements of bone fragments as well as the deformity of the stabilizer under various loading conditions were analyzed. Results: In most cases, the parallel setting of the plates ensures a better stabilization of the bone fragments than the perpendicular configuration. The most difficult conditions of stabilization were obtained for the lateral bone fragment. The value of the fragments' displacements significantly increases for loading directions occurring with ascending flexion angle of the joint. Conclusions: In most cases, the parallel setting of the plates ensures a better stabilization of the bone fragments than the perpendicular configuration.