The thesis is devoted to the studying of the implantation characteristics of the acetabulum in case of developmental dysplasia of the hip (DDH) applicable to surgical technique needs during total hip replacement (THR) procedure.
This thesis is based on the materials of complex prospective stage MSCT-morphometric, radiographic, osteodensitometric, clinical-orthopaedic and biomechanical examination of 59 patients (6 men and 53 women; 81 hip joints) with DDH of Crowe types I-III, who entered the group of pathology, and underwent total hip arthroplasty with selection of AC implantation tactics based on the developed conceptual model, and 35 individuals (5 men and 30 women; 70 hip joints) without signs of pathology of the hip joints, who formed the group of norm. The program of patients’ preoperative examination, in addition to standard methods, included MSCT-examination of the hip and pelvis according to the developed study protocol to determine MSCT-morphometric parameters that comprehensively characterize the area of the planned AC implantation. Evaluation of the THR’s results included a step assessment of the operated extremity weight-bearing function via statometry, clinical and functional evaluation by the method of W. Harris and radiological evaluation of the "endoprosthesis-bone" contact interface by modified Charnley-De-Lee method, with a total 4-year observation period.
An approach to the stratification of the acetabular sectoral deficiency that takes into account the localization and severity of acetabular walls’ undercoverage was developed. According to the proposed approach, there were detected 7 patterns of acetabular sectoral deficiency during DDH Crowe I-III types which allow to predict the risk of instability of different types of acetabular components of the endoprosthesis.
There were developed the method of preoperative assessment of X-ray density of AC implantation site according to topographic landmarks, based on the measurement of the attenuation coefficient of the spongious bone tissue of the supraacetabular area, anterior and posterior acetabular walls. Normal values of the aforementioned coefficient of X-ray density of the spongious bone were defined, as: 272 HU (181; 297), 194 HU (172; 214) and 244 HU (221; 267), respectively.
There were noticed a progressive increasing of the X-ray density of the supraacetabular spongious bone tissue in patients with DDH that correlates with cranial displacement of the femoral head accompanied with progressive decreasing of X-ray density of the anterior and posterior acetabular walls in the projection of its true bed. The X-ray density of the supraacetabular area during DDH Crowe types I, II, III was: 322 HU (290; 354), 388 HU (362; 420), 413 HU (379; 447) respectively.
There were developed the method for predicting the possibility of performing deepening of the acetabular bottom and AC medialization with ensuring its primary stability based on the established normative values of the medial wall thickness in the projection of the lig. teres bed and the center of the planned AC implantation bed. The indices’ values were defined as 4,3 mm (3,3; 4,8) and 7,2 mm (6,2; 7,8), respectively. There were found out a statistically significant increasing of the acetabular medial wall’s thickness, both in the projection of the lig. teres bed, and of the center of AC implantation bed during DDH Crowe I-III types in comparison with group of norm (p <0,0001). There is a significant intragroup variation in the thickness of the medial wall during DDH Crowe II type, which requires precising and individualization of surgical tactics of AC implantation.
There were elaborated a conceptual model-algorithm for selection of AC implantation tactics in patients with DDH based on the proposed preoperative planning techniques, which takes into account a comprehensive assessment of morphological and structural features of the implantation site and allows to select AC design, the method of its implantation and using of bone grafting technique according to exact clinical situation.
Clinical application of the elaborated conceptual model-algorithm for selection of AC implantation tactics in patients with DDH Crowe I-III types during 4-year follow-up period allowed to obtain the following clinical and functional outcomes regarding to the Harris Hip Score Scale: "excellent" - in 13 patients (25,5%), "good" - in 34 (66,7%) and satisfactory results - in 4 (7,8%) patients.
