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Biomedical subjects

M G Benedetti

Publications and source records attributed to M G Benedetti.

27 records · Page 2Linked to original sources
PubMed1998

Data management in gait analysis for clinical applications.

OBJECTIVE: To study the reliability of gait analysis data obtained using the Calibrated Anatomical System Technique (CAST) protocol and to verify the suitability and repeatability of the extraction of a number of parameters from the waveforms obtained. DESIGN: The experimental protocol and the parametric analysis technique were applied on a population of able-bodied subjects. BACKGROUND: The clinical interpretation process of gait data still needs a more accurate analysis of the reliability and repeatability of the measurements and a suitable procedure for data reduction useful for data comparison. METHODS: Gait analysis was performed in 20 able-bodied subjects using a stereophotogrammetric system and a forceplate. 124 parameters relative to time-distance, kinematic and kinetic variables were calculated by means of an automatic procedure and statistically analysed. RESULTS: Most of the parameters were found to be normally distributed with relatively small range of variation. Few of them showed poor repeatability, mostly due to the experimental inaccuracies introduced. Correlation of several gait parameters with age, sex, and speed of progression was also identified.

Journal Article↗
PubMed1997

Application of stereophotogrammetry to total body three-dimensional analysis of human tremor.

This work aims at verifying the possibility of investigating joint rotations, with amplitude and frequency ranges typical of pathological human tremor, using commercially available stereophotogrammetric systems together with signal processing techniques. A rotating disk is used as a mechanical tremor simulator to test the ability of the system to track known marker trajectories both in a large and a small calibrated volume. The performances of standard discrete Fourier transform (DFT) and autoregressive techniques are also evaluated and compared in the signal spectrum estimation. Results obtained from a pathological test subject and their dependence on the processing techniques adopted are also presented. The use of stereophotogrammetry and of the proposed signal spectrum estimation technique allow to quantify both frequency and amplitude content of three-dimensional (3-D) rotations of many human joints simultaneously and therefore to isolate the contribution of each joint to the whole body tremor.

Aged↗
PubMed1996

Position and orientation in space of bones during movement: experimental artefacts.

This paper deals with the experimental problems related to the reconstruction of the position and orientation of the lower limb bones in space during the execution of locomotion and physical exercises. The inaccuracies associated with the relative movement between markers and underlying bone are analysed. Quantitative information regarding this movement was collected by making experiments on subjects who had suffered fractures and were wearing either femoral or tibial external fixators. These latter devices provided frames that were reliably rigid with the bone involved, and hence the possibility of assessing the relative movement between markers mounted on the skin and this bone. Anatomical frames associated with thigh and shank were reconstructed using technical frames based on different clusters of skin markers and their rotation with respect to the relevant bone evaluated. Marker movement was also assessed in subjects with intact musculoskeletal structures using digital videofluoroscopy.

Journal Article↗
PubMed1993

Gait analysis in patients after Van Nes rotationplasty.

Gait was analyzed through kinetic, kinematic, and temporal-distance parameters assessment to evaluate the functional performance of ten children treated by the classical Van Nes rotationplasty (VNR). Van Nes rotationplasty is a surgical procedure, which permits the conversion of the ankle joint into a "pseudo-knee" joint. The data were compared with measurements of a normal population of ten healthy subjects. Significant differences with respect to the normal were found in stride duration, stride length, cadence, velocity, and stance-swing ratio, and in ground-reaction forces parameters, which define the propulsive phase in the prosthetic side and the acceptance phase in the sound side. There were differences in some kinematic parameters as well. Van Nes rotationplasty is acceptable from a biomechanical-functional point of view, particularly with respect to the active control of the pseudo-knee, which allows a smooth and coordinate gait pattern.

Adolescent↗
PubMed1992

Kinematic and isokinetic evaluation of patients with flat foot.

In recent years research into joint physiology and biomechanics of movement has employed high-technology instruments to quantify the parameters which determine whether the behavior of a joint or kinematic chain is normal or pathologic. Motion analysis, featuring evaluation of both kinematics and the foot-ground reaction, enables us to measure the temporal and quantitative events of normal and pathologic gaits. The use of motion analysis in the study of flat foot has confirmed the ability to discriminate between "normal" and pathologic. Analysis of these themes has enabled us to follow the temporal evolution of the quantitative parameters both before and after treatment, which can be either surgical or conservative. Evaluation of the kinematic changes and the foot-ground reaction also provides information about the quality and effectiveness of the corrective treatment. For instance, the change in the subtalar alignment following application of an endo-orthotic implant can be targeted for validation by motion analysis. All of the joints comprised in the kinematic chain of the lower limb work together to achieve a symmetrical, rhythmic, and most of all harmonic gait.

Adolescent↗
PubMedDate not supplied

The influence of clinical and biomechanical factors on the results of valgus high tibial osteotomy.

The results of the surgical treatment of valgus high tibial osteotomy were studied based on clinical and radiographic assessment and gait-analysis in 21 patients affected with arthrotic varus knee. Although tibial osteotomy has been in use for some time now, the reasons for its frequent failure are still not fully understood. A statistical analysis of the clinical and biomechanical parameters taken into account in this study have shown that hypercorrection in valgus is required to unload the medial compartment and to prevent the recurrence of deformity in varus and pain. Walking with the limb extrarotated may also be a compensatory mechanism, in order to reduce the adductor moment in the knee and overloading of the medial compartment.

Adult↗
PubMedDate not supplied

The use of bioabsorbable polymers in reconstruction of the anterior cruciate ligament. A preliminary experiment conducted on bioabsorbable interference screws: bovine model vs. ovine model.

The use of interference screws in the reconstruction of the anterior cruciate ligament has increased over the years. Despite doubtless advantages there are some problems, too, some involving method of fixation, others the metallic nature of the screws. With the purpose of overcoming the latter, the authors evaluated the possibility of using interference screws made of bioabsorbable material. This preliminary study was conducted on two animal models (bovine and ovine); as a comparison parameter the torsional pair of screw insertion was used. A substantial similarity in the results thus obtained was observed that, together with the minor difficulties observed in the surgical field, contributes to the indication of the ovine model as preferential, based also on successive tests of functional validation conducted in vivo.

Absorbable Implants↗
PubMedDate not supplied

Functional evaluation in total hip replacement patients.

An evaluation of total hip replacement patients requires objective criteria that allow for the measurement of any changes in the biomechanics of the prosthesis and the effects of these changes on clinical findings. An evaluation of loading and joint movement during walking in these patients has been dealt with by many authors. In this study 15 patients who had undergone total hip replacement for coxarthrosis primary or secondary to congenital dysplasia were examined by kinematic and kinetic gait analysis, clinical evaluation, and radiographic evaluation of the position of the neocenter of prosthetic joint rotation. The patients with prostheses in congenital dysplasia presented with a pattern of walking that was significantly modified. In agreement with what is reported in the literature proximal positioning had less influence on gait parameters as compared to lateral dislocation. Furthermore, changes in positioning observed did not seem to have negative effects on joint loading, measured indirectly by the calculation of joint moments.

Adult↗