Classifications of Acetabular Defects: Do They Provide an Objective Evidence for Complexity of Revision Hip Joint Arthroplasty? (Critical Literature Review and Own Cases)

The present paper bears discussion in nature and doesn’t claim for any scientific evidence.The purpose is to identify which classification of acetabular defects currently is the most employed in revision hip joint arthroplasty, and how precise this classification reflects the true defect severity and gives the objective grounds for selection of revision implants.Materials and methods. The authors conducted literature analysis in PubMed and eLIBRARY for the last five years. 170 publications in English, German and Spanish languages as well as 15 works in Russian language dedicated to classification of acetabular defects were selected.Results. W.Paprosky classification was found to be the most applicable, namely, in 65,9% of foreign publications and in 100% of Russian papers. AAOS classification was used in 22.9% of cases, Gross and Saleh — in 4.1%, Gustilo and Pasternak — in 1.2%. 5.9% publications reported use of two classifications. The reasons for Paprosky classification popularity is the possibility to evaluate defect basing on standard pelvis x-rays in preoperative stage as well as in retrospective research. At the same time, according to literature, the confidence of Paprosky classification (accuracy of correspondence to intraoperative findings) varies from 16 to 66% for different areas of acetabulum, and during reliability assessment (consistency between different specialists) kappa coefficient varies from 0.14 to 0.75 depending on experience of the specialist and specifics of the defect. One of the possible reason for discrepancies in assessment of defect grade are the iatrogenic and posttraumatic changes of the acetabulum. Nevertheless, Paprosky classification is evolving and, considering additional parameters, like type of defect (contained or non-contained) and pelvic ring continuity, it allows to create a full-fledge algorithm for selection of revision implants and defect replacement which is adequate to the up-to-date surgical needs. At the same time onrush of digital technologies of 3D-visualization considerably expands our possibilities for preoperative defects assessment and offers promising potential for development of new classifications, whose benefits are yet to be evaluated.