Impaction bone grafting for acetabular bone defects replacement in revision hip arthroplasty: biomechanical aspects

Abstract

Introduction. The modern features of the revision hip arthroplasty are the increase of the number early revisions and young age of patients. Bone defect management in this category is especially relevant. The leading role in long-term survival using impaction bone grafting (IBG) is given to the mechanical properties of the graft. The purpose of the study is to explore the mechanical properties of osteoplastic material and determine the effect of cyclic loads on dynamic changes in the position of the acetabular component after revision hip arthroplasty using (IBG). Materials and methods. A single-cycle constrained compression experiment was carried out on morselized xenobone. Cyclic tests were carried out at the second stage of the study. Clinical interpretation of biomechanics was carried out on the radiographic data by changes in the acetabular position. Results. Stress-strain dependences and instantaneous elastic moduli were obtained. The increase of the instantaneous elastic modulus during cyclic tests was obtained by 2.6 times for a “dry” specimen and from 3.9 to 4.7 times with liquid. The shift of the center rotation cranially and laterally was noted in the first case is 2.4 and 1.5 mm, in the second is 14.9 and 9.5 mm, respectively. The change in the inclination was 18.7º in the first case and 19.8º in the second. The Hip Harris Score (HHS) was 97 points in the first case, 53 points in the second. Conclusions: 1. The material used for IBG is subject to deformation in the postoperative period. 2. Compression tests suggested that the deformation of impacted bone graft in the postoperative period gradually tends to reach a plateau, and with the completion of the deformation, migration of the acetabular component stops. 3. A change of the acetabular component position in the absence of a radiolucent line is not an absolute sign of loosening.