Paprosky Classification of Acetabular Bone Loss

The incidence of THA revision has increased substantially during the last decade and is projected to nearly double by 2026 [8, 9]. Aseptic loosening and osteolysis continue to be major challenges in hip reconstruction surgery; planning surgical treatments for these conditions requires accurate preoperative characterizations of the bone loss caused by these conditions, as preoperative planning is essential to ensure the appropriate equipment and prostheses are available. Many different classification schemes have been proposed to describe the extent of periacetabular bone loss in revision THA including those proposed by Paprosky et al. [11], D’Antonio [2] (also known as the American Academy of Orthopaedic Surgeons system [AAOS]), Saleh et al. [13], Gustilo and Pasternak [6], Gross et al. [5], Parry et al. [12], and Engh et al. [3]. These classification schemes differ in that some aim to simplify classification to improve communication and reproducibility [3, 5, 7, 12], whereas others seek to provide detailed anatomic information for defectspecific preoperative planning [2, 6, 7, 11, 13]. Other fundamental differences include the presence or absence of standard anatomic landmarks compared with pure volumetric bone loss independent of the structures affected and the focus on bone stock remaining in contrast to bone stock required for revision [7]. Described in 1994, the Paprosky classification is a commonly used system for classifying acetabular bone loss in revision THA (Fig. 1) [11].