Ovchynnikov O. Dislocation head of endoprosthetic of the hip joint: causes, prevention and treatment.

Object: dislocation of the hip endoprosthesis head. Aim: to increase the effectiveness of total hip arthroplasty by studying the causes, justification and development of methods for the prevention and elimination of the dislocation of the hip endoprosthesis head. Methods: clinical, radiological and computed tomography; biomechanical (graph-analytical method with elements of mathematical modeling) statistical. New knowledge about the causes of dislocations of the implant head, the main of which were elderly, patients violation of the restriction of the volume of movements in the hip joint and orthopedic regime in the postoperative period, overweight, weakness of the hip muscles and the head of the endoprosthesis of small diameter (28 mm and less). For the first time, the positions and components of the endoprosthesis that prevent the occurrence of dislocation of the head of the endoprosthesis were determined by graphic-analytical studies. It was found that the use of a liner with a elevated rim alone or in combination with a large diameter endoprosthesis head and a reduced diameter neck is a measure to prevent dislocations of the endoprosthesis head. It is proved that the restoration of the joint capsule is an important condition for the prevention of dislocation of the implant head. For the first time on the basis of retrospective and prospective analysis of treatment results, the main quantitative criteria for predicting dislocation of the implant head after hip arthroplasty were determined. A method for determining the position of the cup and stem of the hip joint endoprosthesis using radiography makes it possible to diagnose the wrong position of the components of the endoprosthesis, which can lead to dislocation of the implant head. The method of capsuloplasty and installation of endoprosthesis components (in particular, the orientation of the liner elevated rim), which prevent the occurrence of dislocation of the implant head in the case of total and unipolar hip arthroplasty, has been improved. The use of the proposed methods of prevention and treatment of dislocation of the implant head allowed to obtain positive results of treatment in 100% in the period of observation up to 4 years. The results of the study were introduced into the clinical practice of the SI "Sytenko Institute of Spine and Joint Pathology National Ukrainian Academy of Medical Sciences", KOZZ "Kharkiv Regional Clinical Hospital - Emergency Care Center and Disaster Medicine" of the Kharkiv Regional Council, KZOZ "Kharkiv Regional Clinical Traumatological Hospital" Kharkiv Regional State Administration. Traumatology and Orthopaedics.