A Review Paper 534 The American Journal of Orthopedics ® Abstract Complex primary total hip arthroplasty (THA) is defined as primary THA in patients with compromised bony or soft-tissue states, including but not limited to dysplastic hip, ankylosed hip, prior hip fracture, protrusio acetabuli, certain neuromus- cular conditions, skeletal dysplasia, and previous bony proce- dures about the hip. Intraoperatively, provisions must be made for the possible use of modular implants and/or bone grafts. In this article, we review the principles of preoperative, intraop- erative, and postoperative management of patients requiring a complex primary THA. U .S. surgeons annually perform more than 150,000 total hip arthroplasties (THAs), 90% of which are primary procedures. 1 Improved surgical technique and instrumentation have expanded the clinical indications for THA to include patients who previously would not have been considered eligible for this procedure. Such complex cases, which often require mod- ular implants 2 and/or bone grafting similar to that used in revision arthroplasty, fall into the categories of dysplastic hip, ankylosed hip, fractures about the hip, protrusio acetabuli, neuromuscular conditions, skeletal dysplasias, and previous bony procedures about the hip. Indications for complex THA include pain not relieved with conservative treatment and functional impair- ment with radiographic evidence of hip degeneration. Contraindications include active sepsis and major medi- cal comorbidities. Preoperative range of motion (ROM) should be assessed, the Thomas test should be used to determine presence of flexion contracture, and limb-length discrepancy should be documented with the patient in the supine and upright positions (with use of blocks for stand- ing, allowing the extent of limb-length correction to be estimated). 3 Standard anteroposterior (AP) and lateral x-rays of the hips should reveal underlying hip pathology and facili- tate surgical planning and component templating (Figure 1). 4 Special imaging modalities, including computed tomography (CT) of the hip, may be useful in complex hip arthroplasty. CT provides 3-dimensional information about anterior and posterior column deficiencies, socket size, and thickness of the anterior and posterior walls and allows visualization of the external iliac vessels to ensure Surgical Challenges in Complex Primary Total Hip Arthroplasty Sathappan S. Sathappan, MD, Eric J. Strauss, MD, Daniel Ginat, BS, Vidyadhar Upasani, BS, and Paul E. Di Cesare, MD Dr. Sathappan is Fellow, Dr. Strauss is Resident, Mr. Ginat is Medical Student, and Mr. Upasani is Medical Student, Department of Orthopedic Surgery, Musculoskeletal Research Center, New York University Hospital for Joint Diseases, New York, New York. Dr. Di Cesare is Professor and Chair, Department of Orthopaedics, University of California at Davis School of Medicine, Sacramento, California. Work conducted at Department of Orthopedic Surgery, Musculoskeletal Research Center, New York University Hospital for Joint Diseases, New York, New York. Requests for reprints: Paul E. Di Cesare, MD, Department of Orthopaedics, University of California at Davis School of Medicine, 4860 Y Street, Suite 3800, Sacramento, CA 95817 (tel, 916-734-2958; fax, 916-734-7904; e-mail, pedicesare@aol.com). Am J Orthop. 2007;36(10):534-541. Copyright Quadrant HealthCom Inc. 2007. All rights reserved. Figure 1. Preoperative (A) and postoperative (B) anteropos- terior x-rays of a 68-year-old woman with Paget disease who presented with radiodense sclerotic acetabular bone requiring cementing of the acetabular liner to achieve good fixation. A B