Malyk R. Biomechanical substantiation of the choice of tactics for surgical treatment of patients with malignant bone tumors of the proximal femur.

Object: malignant bone tumors of the proximal femur. Aim: To determine the volume of limb-salvage surgery in patients with malignant tumors of the proximal femoral bone by means of biomechanical substantiation of indications for the use of reconstructive techniques. Methods: Radiation (X-ray, computer tomography and magnetic resonance imaging); ultrasound investigation; clinical; mathematical modeling; statistical. For the first time, a working classification of soft tissue lesions was created based on the results of a spiral computer tomography, by the extra-bone component of the tumor of the proximal femur in accordance with the spread of the tumor process along the area of the upper half of the thigh, the direction of growth and the degree of severity of the tumor process. For the first time, biomechanical disturbances were identified with the help of mathematical modeling in the form of changes in the workload of the bonfire after resection of the affected soft tissue tumors in the hip joint region. New knowledge on changing the direction of action of the resulting force of gravity load in case of significant defects in hip flexion. The decrease in the load to 261.4% of the body weight on the anterior parts of the acetabulum and a maximum of 24.3% in the vertical direction to the phase of the limb of the limb and to a maximum of 45.5% reduction of the head force to the bonfire. These changes of load were accepted as a prognostic sign of the violation lower limb function with the risk of hip instability. It is proved that the technique of myoplasty in the case of the formation of defects of the hip muscles with m. vastus lateralis is expedient in the functional aspect, since it allows the stock to compensate for the altered changes in the force of the gravity loading. On the basis of the developed working classification, the distribution of the extracortical component of the proximal femur tumor in soft tissue of the thigh is supplemented with criteria for choosing the method of limb-salvage surgery of patients with malignant tumors of the proximal femur, which increases its efficacy and quality of life of the patient. Computer program was developed for evaluation and assistance in the classification of the distribution of the proximal component of the proximal tumor of the proximal femur in the soft tissue of the thigh allows the results of the analysis of the computer tomography to be quickly obtained and to clarify the indications to the appropriate surgery. Based on the obtained results of mathematical analysis of normal walking simulation on musculoskeletal models with an estimation of the functioning of the hip joint, evidence was added to the selection of optimal surgical tactics at the reconstructive stage limb-salvage surgery in patients with malignant tumor of proximal femur, which made it possible to apply an individual approach and adequate tactics before treatment of this category of patients and, accordingly, increase the efficiency of surgical treatment, improve functional results and reduce the percentage of postoperative complications. The results of the research are introduced into clinical practice in SI "Sytenko Institute of Spine and Joints Pathology of National Academy of Medical Sciences of Ukraine", KUZ "Kharkiv Regional Clinical Hospital - Emergency and Disaster Medicine Centre", KUZ "Kharkiv Regional Traumatologist Hospital", KUZ "Kharkiv Multidisciplinary Hospital № 18", KU "Rivne Regional Clinical Hospital", KUZ "1st Poltava City Clinical Hospital". Also results of the research are introduced into study process in Traumatology and Orthopaedics Departments of "Kharkiv National Medical University", "Ukrainian Medical Dental Academy", "Kharkiv Medical Academy of Postgraduate Education". Traumatology and Orthopaedics.