Sulima O. Revision replacement with асерtic instability of acetabular endoprosthesis component and defects of hip cavity

The dissertation is intended for results improvement in treatment of patients with aceptic instability of acetabular component of hip joint endoprosthesis with defects of bony tissues by means of causes determination of defects appearance, development of early noninvasive diagnosis of instability and establishment a differentiated technique to revision replacement of patients with bony bed defects. According to the results of clinical-roentgenologic investigation of 188 patients with aceptic loosening of acebular component of endoprothesis in average in 5,2±2,8 years after revision it has been shown that namely the volume of bony bed deficiency is a main definition of the defect that leads to component migration and correlates conversely with its function. In accordance with 106 functional studies it has been determined early sonographic and roentgenodensitometric criteria of diagnosis for aceptic loosening endoprosthesis components. On the basis of morphologic investigation 68 bioptates of tissue around instable component it has been revealed the presence of nonspecific granulomatous inflammation of high extent of spreading with dense macrophagal infiltration and macrophagal - gigantocellular reaction of foreign bodies. It has been shown the direct dependence between inflammation manifestation and amount of coagulative ischemic necroses of bony tissue that leads to defects appearance of hip cavity. In accordance with 112 microbiologic tests of surgical material in patients with aceptic instability of primary endoprosthesis of hip joint it has been revealed the presence of microorganisms in culture in 43,5 % of patients and by means of the microscope they were observed in 65,2 % of patients. Contamination by microorganisms around prosthetic tissues influences on manifestation of clinical picture of instability and enlarges the size of hip cavity defects, has made worse the results of revision prosthetics that stipulates expediency of application of corresponding antibioticoprophylaxis of complications. The criterion of serologic diagnosis of inflammatory reaction around instable endoprosthesis has been determined (concentrationC-RB< 24mg/ll and the presence of positive reaction of agglutination with autostrains). According to the results of mathematical modelling it has been found that disorders of implantation position of artificial cavity leads to decrease of area its contact with bony bed, enlarges mechanical stress in bony tissue beyond the limits of its strength (50 kG/cm2). Displacement of implantation angle of revision cavity more than 12? and decrease contact area with bony bed lower than 62 % is biomechanical prerequisite of revision endoprosthesis destabilization.The defects exceeding 50 cm3 without their plastic replacement lead to appearance of overload zones and do not allow to reach fixation of revision cementless acetabular cjmponent with press fit. At defects localization in projection of zone 2. According to DeLee Charnley, "roofs" of cavity,stress reaches 270 kG/cm2. Application of cement type fixation and bony cement for plasticity does not decrease stress of residual bone. The results of revision prosthetcs have been followed up from 3 to 10 years in average 5,2±2,8 years. Differentiated technique of revision prosthetics in patients with defects of hip cavity has allowed to obtain the following results: excellent results were noted in 67 cases (35,6 %), good results included 84 cases (44,7 %), satisfactory results were marked in 33 cases (17,5 %) and unsatisfactory results included 4 cases (2 %). Excellent and good results were obtained at application of cementless type of fixation for component revision (90 %), implantation according to recommended positions of revision component, at overlapping by bone more than 70 % of revision component, at complete replacement of the defects by osteoplastic materials with transplant contact and maternal bed more 50 % including application of additional support constructions. Exactly these techniques are perspective for revision prosthetics. Disorders of these principles lead to complications and unsatisfactory results. The terms of consolidation and reconstruction depend on the volume of utilized plastic material and the percent of transplant contact and maternal bed.