Biomedical subjects

F Catani

Publications and source records attributed to F Catani.

At least 37 records · Page 2Linked to original sources

PubMed1999

A geometric model of the human ankle joint.

A two-dimensional four-bar linkage model of the ankle joint is formulated to describe dorsi/plantarflexion in unloaded conditions as observed in passive tests on ankle complex specimens. The experiments demonstrated that the human ankle joint complex behaves as a single-degree-of-freedom system during passive motion, with a moving axis of rotation. The bulk of the movement occurred at the level of the ankle. Fibres within the calcaneofibular and tibiocalcaneal ligaments remained approximately isometric. The experiments showed that passive kinematics of the ankle complex is governed only by the articular surfaces and the ligaments. It was deduced that the ankle is a single-degree-of-freedom mechanism where mobility is allowed by the sliding of the articular surfaces upon each other and the isometric rotation of two ligaments about their origins and insertions, without tissue deformation. The linkage model is formed by the tibia/fibula and talus/calcaneus bone segments and by the calcaneofibular and tibiocalcaneal ligament segments. The model predicts the path of calcaneus motion, ligament orientations, instantaneous axis of rotation, and conjugate talus surface profile as observed in the experiments. Many features of ankle kinematics such as rolling and multiaxial rotation are elucidated. The geometrical model is a necessary preliminary step to the study of ankle joint stability in response to applied loads and can be used to predict the effects of changes to the original geometry of the intact joint. Careful reconstruction of the original geometry of the ligaments is necessary after injury or during total ankle replacement.

Ankle Injuries↗

PubMed1999

Flat foot functional evaluation using pattern recognition of ground reaction data.

OBJECTIVE: Main purpose of this study was to apply quantitative gait analysis and statistical pattern recognition as clinical decision-making aids in flat foot diagnosis and post-surgery monitoring. DESIGN: Statistical pattern recognition techniques were applied to discriminate between normal and flat foot populations through ground reaction force measurements; ground reaction forces time course was assumed as a sensible index of the foot function. BACKGROUND: Gait analysis is becoming recognized as an important clinical tool in orthopaedics, in pre-surgery planning, post-surgery monitoring and in a posteriori evaluation of different treatment techniques. Statistical pattern recognition techniques have been utilized with success in this field to identify the most significant variables of selected motor functions in different pathologies, and to design classification rules and quantitative evaluation scores. METHODS: Ground reaction forces were recorded during free speed barefoot walks on 28 healthy subjects, and 28 symptomatic flexible flat foot children selected for surgical intervention. A new feature selection algorithm, based on heuristic optimization, was applied to select the most discriminant ground reaction forces time samples. A two-stage pattern recognition system, composed by three linear feature extractors, one for each ground reaction force component, and a linear classifier, was designed to classify the feet of each subject using the selected features. The output of the classifier was used to define a functional score. RESULTS: The classifier assigned the ground reaction force patterns performed by each subject into the right class with an estimated error of 15%, corresponding to an assignment error for each subject's foot of 9%. The most discriminant ground reaction forces time samples selected are in full agreement with the pathophysiology of the symptomatic flexible flat foot. The obtained score was utilized to monitor the 1 and 2 years post-operative functional recovery of two differently treated subgroups of 32 flexible flat foot subjects. CONCLUSIONS: Statistical pattern recognition techniques are promising tools for clinical gait analysis; the obtained score provides important functional information that could be used as a further aid in the clinical evaluation of flat foot and different surgical treatment techniques. RELEVANCE: Symptomatic flexible flat foot surgical decision making is frequently difficult because of the lack of objective criteria to assess functional abnormalities of the foot/ankle complex. Gait analysis and statistical pattern recognition can give us parameters with which to characterize "functional" flat foot. Moreover, we can objectively follow up the recovery of the foot/ankle complex function after surgical treatment.

Algorithms↗

PubMed1999

An anatomically based protocol for the description of foot segment kinematics during gait.

OBJECTIVE: To design a technique for the in vivo description of ankle and other foot joint rotations to be applied in routine functional evaluation using non-invasive stereophotogrammetry. DESIGN: Position and orientation of tibia/fibula, calcaneus, mid-foot, 1st metatarsal and hallux segments were tracked during the stance phase of walking in nine asymptomatic subjects. Rigid clusters of reflective markers were used for foot segment pose estimation. Anatomical landmark calibration was applied for the reconstruction of anatomical landmarks. BACKGROUND: Previous studies have analysed only a limited number of joints or have proposed invasive techniques. METHODS: Anatomical landmark trajectories were reconstructed in the laboratory frame using data from the anatomical calibration procedure. Anatomical co-ordinate frames were defined using the obtained landmark trajectories. Joint co-ordinate systems were used to calculate corresponding joint rotations in all three anatomical planes. RESULTS: The patterns of the joint rotations were highly repeatable within subjects. Consistent patterns between subjects were also exhibited at most of the joints. CONCLUSION: The method proposed enables a detailed description of ankle and other foot joint rotations on an anatomical base. Joint rotations can therefore be expressed in the well-established terminology necessary for their clinical interpretation. RELEVANCE: Functional evaluation of patients affected by foot diseases has recently called for more detailed and non-invasive protocols for the description of foot joint rotations during gait. The proposed method can help clinicians to distinguish between normal and pathological pattern of foot joint rotations, and to quantitatively assess the restoration of normal function after treatment.

Adult↗

PubMed1999

A model-based method for the reconstruction of total knee replacement kinematics.

A better knowledge of the kinematics behavior of total knee replacement (TKR) during activity still remains a crucial issue to validate innovative prosthesis designs and different surgical strategies. Tools for more accurate measurement of in vivo kinematics of knee prosthesis components are therefore fundamental to improve the clinical outcome of knee replacement. In the present study, a novel model-based method for the estimation of the three-dimensional (3-D) position and orientation (pose) of both the femoral and tibial knee prosthesis components during activity is presented. The knowledge of the 3-D geometry of the components and a single plane projection view in a fluoroscopic image are sufficient to reconstruct the absolute and relative pose of the components in space. The technique is based on the best alignment of the component designs with the corresponding projection on the image plane. The image generation process is modeled and an iterative procedure localizes the spatial pose of the object by minimizing the Euclidean distance of the projection rays from the object surface. Computer simulation and static/dynamic in vitro tests using real knee prosthesis show that the accuracy with which relative orientation and position of the components can be estimated is better than 1.5 degrees and 1.5 mm, respectively. In vivo tests demonstrate that the method is well suited for kinematics analysis on TKR patients and that good quality images can be obtained with a carefully positioning of the fluoroscope and an appropriate dosage. With respect to previously adopted template matching techniques, the present method overcomes the complete segmentation of the components on the projected image and also features the simultaneous evaluation of all the six degrees of freedom (DOF) of the object. The expected small difference between successive poses in in vivo sequences strongly reduces the frequency of false poses and both the operator and computation time.

Algorithms↗

PubMed1999

Myoelectric activation pattern during gait in total knee replacement: relationship with kinematics, kinetics, and clinical outcome.

Gait usually presents an excellent improvement after total knee replacement. Nevertheless, some abnormalities persist even after a long period of time. The abnormal knee patterns have been attributed to several possible causes, such as implant geometry and surgical technique, posterior cruciate ligament sparing/sacrificing, preoperative "stiff-knee" pattern due to pain and altered biomechanics, weakness of the extensor muscles, preoperative arthritic pattern, proprioceptive deficiency, and multijoint degenerative involvement. Cocontraction of the knee flexors and extensors is a common strategy adopted to reduce strain and shear forces at the joint, but it increases compressive forces and joint loading. Even in patients with an excellent functional score, the duration of the implant may be compromised by an altered neuromuscular control of the knee. In this paper, we report a single case study carried out over two years on a patient that underwent total knee replacement. The aim of this work is to show that quantitative gait analysis is essential to augment the understanding of the mechanisms underlying gait, thus enabling clinicians to adapt the rehabilitation program to the specific patient. Although the limits of single case reports are obvious, we believe that this evaluation methodology could be beneficial for assessing the effectiveness of rehabilitation programs aimed at achieving an active control of the knee during gait through a correct muscular activation pattern.

Biomechanical Phenomena↗

PubMed1999

Analysis of function after intra-articular fracture of the os calcis.

Fractures of the os calcis with intra-articular involvement can cause difficulty in treatment and can result in abnormal function throughout the ankle-foot complex. We evaluated the function of the ankle-foot complex and the overall gait pattern after fracture of the os calcis, and we compared the results of surgical and nonsurgical treatment. Those in whom the geometry of the os calcis and joint was restored by reconstructive surgery had better compensation of gait and a better clinical-functional score. Complex disturbances in gait were found in the group of patients that did not undergo open reduction or internal fixation.

Adult↗

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↗

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↗

PubMed1995

Position and orientation in space of bones during movement: anatomical frame definition and determination.

This paper deals with methodological problems related to the reconstruction of the position and orientation of the human pelvis and the lower limb bones in space during the execution of locomotion and physical exercises using a stereophotogrammetric system. The intention is to produce a means of quantitative description of joint kinematics and dynamics for both research and application. Anatomical landmarks and bone-embedded anatomical reference systems are defined. A contribution is given to definition of variables and relevant terminology. The concept of anatomical landmark calibration is introduced and relevant experimental approaches presented. The problem of data sharing is also addressed. This material is submitted to the scientific community for consideration as a basis for standardization. RELEVANCE: In order to make movement analysis effective in the solution of clinical problems, a structured conceptual background is needed in addition to standardized definitions and methods. Technical solutions which make data sharing and relevant data banks possible are also of primary importance. This paper makes suggestions in this context.

Journal Article↗

PubMed1994

Surgical repair of achilles tendon ruptures using polypropylene braid augmentation.

Surgical repair in fresh rupture of the Achilles tendon should be considered in active patients and athletes to restore their preinjury level of activity. Fifteen cases of Achilles tendon rupture underwent surgical repair using interpositional augmentation. This technique provides an immediate mechanical strength of the repair, avoiding the need for a postoperative plaster cast and allowing immediate motion of the ankle. No wound infection, scar adherence of the skin to the tendon, or rerupture of the tendon is present in this series. All patients were subjectively satisfied with the results and returned to their preinjury level of activity. Objectively, isokinetic assessment revealed no significant difference, as per t-test evaluation (P < .05), between the operated leg and the controlateral one.

Achilles Tendon↗

PubMed1994

Osteoid osteoma of the lateral cuneiform bone.

An unusual case of osteoid osteoma is reported emphasizing the necessity of a careful history and physical examination combined with an adequate imaging supply. Treatment was surgical with an en bloc excision of the lesion.

Adult↗

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↗

PubMed1992

Functional evaluation of patients fitted with total knee prostheses.

Degenerative or inflammatory diseases of the knee joint account for a large proportion of diseases affecting the elderly. Treatment aims to eliminate pain, correct the deformity and maintain complete joint mobility. In cases of total joint degeneration, fitting of a joint prosthesis is the technique currently favoured since elimination of pain and correction of the deformity, accompanied by recovery of joint mobility (the fundamental requirements for normal everyday life) can only be obtained if the knee joint is completely replaced. With the discovery of new materials and increasingly sophisticated knowledge about articular mechanics, the knee prosthesis, although more recent than the hip prosthesis, has become ever more widespread to the point that it now represents an irreplaceable aid in the treatment of this common disease. The clinical results obtained are already stable and particularly encouraging and prosthesis design is sophisticated and accurate. There is, however, still the suspicion that current prostheses can be considered "rudimentary" in comparison with the physiological and biomechanical behaviour of the human joint. We therefore wanted to begin an evaluation using a gait analysis system to assess patients fitted with knee prostheses. The first impressions gained in this study are the subject of this article.

Activities of Daily Living↗

PubMed1986

[Systemic and nonsystemic causes of pathological mandibular fractures].

The problem of pathological fractures of the lower jaw with particular reference to their aetiology is examined in the light of personal experience. Odontogenic and hematogenic osteomyelitis, primary and metastatic tumours, degenerative lesions, traumas, inclusions of the teeth and the whole apparatus are discussed individually.

Fractures, Spontaneous↗

PubMed1986

[Hand-Schüller-Christian syndrome arising in the mandible. A case report].

The history of Letterer-Siwe, Hand-Schüller-Christian disease, and eosinophilic granuloma of the bone, and the evolution of the concept of grouping them together under the common term of histiocytosis X are presented. The characteristics of the disease, with particular emphasis on oral manifestations, are reviewed. The therapy for the disease is briefly outlined. One case of Hand-Schüller-Christian syndrome is presented. The discussion is focused on the problem of chemotherapy in disseminated forms.

Adult↗

PubMedDate not supplied

Dislocation of central venous catheters in paediatric patients.

Children have limited venous access possibilities; therefore, when long-term therapy is necessary, it is better to place a catheter in a central vein. The Port catheter, totally implanted, is less exposed to the risk of infection and permits a normal life. However, there is the possibility of the displacement or fragmentation of the catheter that can be diagnosed initially only by clinical symptoms and later by a chest X-ray. We report a case of disconnection between the Port catheter and the reservoir resulting in catheter migration to the left pulmonary artery.

Cardiac Catheterization↗

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↗