36 CCJR SUPPLEMENT TO THE BONE & JOINT JOURNAL  MANAGEMENT FACTORIALS IN TOTAL HIP ARTHROPLASTY Acetabular distraction AN ALTERNATIVE FOR SEVERE ACETABULAR BONE LOSS AND CHRONIC PELVIC DISCONTINUITY N. P. Sheth, C. M. Melnic, W. G. Paprosky From Hospital of the University of Pennsylvania, Philadelphia, United States  N. P. Sheth, MD, Assistant Professor University of Pennsylvania, Department of Orthopaedic Surgery, 800 Spruce Street, 8th Floor Preston Building, Philadelphia, Pennsylvania 19107, USA  C. M. Melnic, MD, Resident Hospital of the University of Pennsylvania, Department of Orthopaedic Surgery, 3400 Spruce Street, 2 Silverstein, Philadelphia, 19104, USA  W. G. Paprosky, MD, Professor Rush University, Midwest Orthopaedics, 1655 West Harrison Street, Chicago, Illinois 60612, USA Correspondence should be sent to Dr C. M. Melnic; e-mail: christopher.melnic@ uphs.upenn.edu ©2014 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.96B11. 34455 $2.00 Bone Joint J 2014;96-B(11 Suppl A):36–42. Acetabular bone loss is a challenging problem facing the revision total hip replacement surgeon. Reconstruction of the acetabulum depends on the presence of anterosuperior and posteroinferior pelvic column support for component fixation and stability. The Paprosky classification is most commonly used when determining the location and degree of acetabular bone loss. Augments serve the function of either providing primary construct stability or supplementary fixation. When a pelvic discontinuity is encountered we advocate the use of an acetabular distraction technique with a jumbo cup and modular porous metal acetabular augments for the treatment of severe acetabular bone loss and associated chronic pelvic discontinuity. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):36–42. Acetabular bone loss is a complex problem in revision total hip replacement (THR). Revision THR is becoming more common in orthopae- dics due to more primary THRs being per- formed for broader indications in younger patients. Kurtz et al 1,2 have shown that the need for primary THR will grow 601% by 2030. Increasing patient life expectancy along with improved implant longevity is likely to result in more complex revisions in the future, including the management of pelvic disconti- nuity. Discontinuities can be described as being acute (e.g. a fracture created during cup inser- tion or fracture resulting from a fall) or chronic in that such a discontinuity acts similarly to a fibrous nonunion. Berry et al 3 showed that pel- vic discontinuities are more common in women and patients with rheumatoid arthritis. There are three key factors that influence the treatment of pelvic discontinuity; the remain- ing host bone stock, the potential for biological ingrowth, and the potential for healing of the discontinuity. There are several treatment options to address this complex problem including posterior column plating for acute pelvic discontinuity, the use of a jumbo cup or an acetabular cage, acetabular allograft recon- struction with a cage and cemented liner, a cup-cage construct, or a custom triflange ace- tabular component. An alternative treatment is acetabular dis- traction with a jumbo cup and modular porous metal acetabular augmentation. This option was created in response to suboptimal out- comes in the management of severe acetabular defects associated with pelvic discontinuity. 4 This review article discusses aetiology, classifi- cation, indications, contraindications, surgical technique, post-operative management, and clinical results. Aetiology of acetabular bone loss Acetabular bone loss may result from peri- prosthetic infection, osteolysis, stress shield- ing, peri-prosthetic fracture, metastatic lesions, and iatrogenic bone loss during component removal. Improved long-term survival has been seen with cementless acetabular compo- nents when compared with cemented devices. 5 However, asymptomatic osteolysis and stress shielding associated with cementless fixation may result in significant compromise of remaining acetabular bone stock. A CT scan pre-operatively can be used as an adjunct to radiographs to better define the severity and location of acetabular bone loss. 6 Bone loss classification The most widely used classification is that described by Paprosky. 7-10 This system is based on the location of the hip centre of rotation in reference to the superior obturator line, osteo- lysis of the ischium and the tear drop, and the integrity of the ilioischial line (Kohler’s line) (Fig. 1). These four variables allow for objec- tive assessment of bone loss involving the pos- terior column, superior dome, and the medial acetabular wall. 7 The Paprosky classification describes three different types of bone defects. 8 In type I