Contributions to the Study on the Effects of Incorrect Implantation of Knee Prostheses Depending on the Degree of Varus / Valgus.

INTRODUCTION: The human knee is one of the most complex human joints, by the number of components, by the stresses to which it is subjected, by the complicated spatial geometry of the components and by the existence of multiple contacts between different components. MATERIAL AND METHOD: A series of modern devices and equipment that were used for the three-dimensional reconstruction of the components of the analyzed systems. RESULTS: Also, the elements of a knee prosthesis were modeled in a parameterized virtual environment and six orthopedic systems were compared. These systems have been studied using the finite element method using loads specific to normal human gait. DISCUSSION: The results obtained consisting of maps of displacements, deformations and stresses were stored, analyzed and compared. CONCLUSIONS: Finally, important conclusions were highlighted.

Effects of malalignment angle on the contact stress of knee prosthesis components, using finite element method.

In this paper, the complex 3D virtual model of the prosthetic knee is obtained using embedded applications: DesignModeler and SpaceClaim under ANSYS Workbench 14.5 software package. A number of six cases of prosthetic knee joint assembly, depending on the malalignment angle, are developed. Stress maps and the values of the maximum von Mises stress on the three prosthesis components: polyethylene insert, tibial component and femoral component, for all studied prosthetic knee assemblies were obtained. The results show that as the malalignment angle increases, the values of von Mises stresses increase in all prosthesis components. The parameterized virtual models of the knee prosthesis components allow different changes in shape or dimensions, which can lead to the optimization of the implant and to the improvement of the prosthetic knee biomechanics.

Experimental measurement of flexion-extension movement in normal and corpse prosthetic elbow joint.

This paper presents a comparative experimental study of flexion-extension movement in healthy elbow and in the prosthetic elbow joint fixed on an original experimental bench. Measurements were carried out in order to validate the functional morphology and a new elbow prosthesis type ball head. The three-dimensional (3D) model and the physical prototype of our experimental bench used to test elbow endoprosthesis at flexion-extension and pronation-supination movements is presented. The measurements were carried out on a group of nine healthy subjects and on the prosthetic corpse elbow, the experimental data being obtained for flexion-extension movement cycles. Experimental data for the two different flexion-extension tests for the nine subjects and for the corpse prosthetic elbow were acquired using SimiMotion video system. Experimental data were processed statistically. The corresponding graphs were obtained for all subjects in the experimental group, and for corpse prosthetic elbow for both flexion-extension tests. The statistical analysis has proved that the flexion angles of healthy elbows were significantly close to the values measured at the prosthetic elbow fixed on the experimental bench. The studied elbow prosthesis manages to re-establish the mobility for the elbow joint as close to the normal one.

New technical procedure involving Achilles tendon rupture treatment through transcutaneous suture.

The Achilles tendon is the widest tendon of the human body. Achilles tendon belongs to the extrasynovial tendons group and this allows it a faster recovery, thanks to local hematoma from the peritenon, necessary for the scarification. We concluded that in Achilles tendon rupture treatment it is essential to maintain the tendon covering skin integrity, the peritendinous integrity, to maintain the local hematoma formed during and after tendon rupture, reattaching the ruptured tendon heads and maintain them in this position by suturing them and by relaxing the sural triceps muscle. The percutaneous suture requires five pairs of mirror micro-incisions (5 mm) on one side and the other of the tendon. It is necessary for one of the pairs to be placed to the rupture level. With a surgical needle, we arm the proximal and distal heads of the tendon by different threads. By traction and muscular relaxation, we bring in contact the two ruptured heads and then we knot together the arming threads. The inferior member was cast immobilized in relaxing position for the sural triceps muscle for a 45 days period. Using this technique, we have operated 15 cases in our Clinic. In all the cases, we obtained a healing by first intention of the tegument micro-incisions. After the cast immobilization suppression, during 30 days the patients were in a recovery program. At the end of this program, they have recovered completely the dorsal and plantar flexion and the walking. In four months after the surgery, the esthetic of the area is completely restored, this technique being the only surgical technique that realizes this recovery.

Collision tumor of recto-sigmoidian junction - case presentation.

Collision tumors of the colon are rare. A 64-year-old man was referred on Emergency County Hospital, Craiova, Romania for the evaluation of intestinal obstruction. Colonoscopy demonstrates the presence of about 9/5 cm sized mass in the rectosigmoid junction. After surgical resection, the rectosigmoid lesion was histopathologically composed of two distinct lesions: mucoid adenocarcinoma in the superficial layer and poorly differentiated neuroendocrin carcinoma in the deeper layer. A rectosigmoid tumor showed two distinct tumors with no admixture or transposition of two neoplastic components. A lymph node metastatic deposit contained both tumors. Immunohistochemical stainings were consistent with mucinous adenocarcinoma and neuroendocrine carcinoma of the two neoplasms. We report this case of colonic collision tumor (mucoid adenocarcinoma and neuroendocrine carcinoma) and review of the literature.

The chick chorioallantoic membrane: a model of short-term study of Dupuytren's disease.

Dupuytren's disease is a progressive fibroproliferative disorder that impairs hand function by altering the normal structures of the palmar fascial bands. Nodules composed almost entirely of myofibroblasts and cords are pathognomonic of Dupuytren's disease. The myofibroblasts express alpha-smooth muscle actin that is especially involved in development of the disease. We aimed to evaluate whether the xenograft of Dupuytren's fibromatosis taken from operating room and transplanted on chick chorioallantoic membrane (CAM) survives with its histological and immunohistological features. Fresh samples obtained from eight patients with Dupuytren's disease were minced and immediately inoculated onto 24 CAMs of 8-day-old chick embryos. The implanted CAMs were examined daily by stereomicroscopy and finally the xenografts were examined and characterized in histological sections using a panel of antibodies. The xenografts were incorporated into the CAMs 6-7 days after transplantation, continued to grow and stimulated angiogenesis in the chick embryo CAMs. The CAMs vessels entered the xenografts and anastomosed with the newly formed xenografts vessels (CD34+ and CD105+) those containing nucleated chick erythrocytes. Myofibroblasts (α-SMA+) and macrophages (CD68+) were readily recognized in the xenograft thickness. We concluded that the xenografts of Dupuytren's fibromatosis transplanted onto chick embryo CAMs continued to develop and preserved the histological and immunohistological features.

Analysis of neuromuscular parameters in patients with multiple sclerosis and gait disorders.

UNLABELLED: Gait is a motor activity that requires understanding the dynamics and functional anatomical elements that make possible its cyclical conduct. Patients with multiple sclerosis record impaired balance and gait due to the process of demyelination, disorders that can be estimated by quantifying neuromuscular and cortical parameters. The aim of this paper is to present both an analysis of these parameters in the thigh muscles and an evaluation of cortical parameters obtained by visual evoked potentials (VEP). PATIENTS AND METHODS: The study was conducted on a group of 13 patients (mean age 38 years) with multiple sclerosis (MS), who had clinically detectable gait disturbance. Evaluation methods used were tensiomyography (TMG) and VEP, the monitored parameters were: contraction time (Tc), stance time (Ts), displacement (Dm), if TMG in the two muscle groups of the thigh (biceps femoris and right femoris), and if VEP the assessed waves were N75, P100, N135-145. RESULTS: There were estimated the average values of latency and duration of the three analyzed waves in VEP, the values of wave N135-145 were far higher than physiological values. In terms of TMG values, they results indicate the existence of a clear right-left functional asymmetry. DISCUSSION AND CONCLUSIONS: Analyzing these results, we note an increase in the muscular tone of the groups studied, a functional asymmetry agonist/antagonist, low speed response to stimulus. Regarding VEP wave parameters, we find significant variations of these waves' latencies, particularly of P100 wave, while the duration of these waves did not register significant figures. In conclusion, we can emphasize a change in muscle structure with predominantly type I muscular fibers and inter-neuronal connections between areas of the association to substitute the lesions occurred in specific areas.