Total Hip Arthroplasty for Femoral Neck Fracture Is Not a Typical DRG 470 : A Propensity-matched Cohort Study

Background Hip fractures are a major public health concern. For displaced femoral neck fractures, the needs for medical services during hospitalization and extending beyond hospital discharge after total hip arthroplasty (THA) may be different than the needs after THA performed for osteoarthritis (OA), yet these differences are largely uncharacterized, and the Medicare Severity Diagnosis-Related Groups system does not distinguish between THA performed for fracture and OA. Questions/purposes (1) What are the differences in inhospital and 30-day postoperative clinical outcomes for THA performed for femoral neck fracture versus OA? (2) Is a patient’s fracture status, that is whether or not a patient has a femoral neck fracture, associated with differences in in-hospital and 30-day postoperative clinical outcomes after THA? Methods The National Surgical Quality Improvement Program (NSQIP) database, which contains outcomes for surgical patients up to 30 days after discharge, was used to identify patients undergoing THA for OA and femoral neck fracture. OA and fracture cohorts were matched one-to-one using propensity scores based on age, gender, American Society of Anesthesiologists grade, and medical comorbidities. Propensity scores represented the conditional probabilities for each patient having a femoral neck fracture based on their individual characteristics, excluding their actual fracture status. Outcomes of interest included operative time, length of stay (LOS), complications, transfusion, discharge destination, and readmission. There were 42,692 patients identified (41,739 OA; 953 femoral neck fractures) with 953 patients in each group for the matched analysis. One of the authors (JML) lists the following relevant financial activities outside of this work and/or any other relationships or activities that readers could perceive to have influenced, or that give the appearance of potentially influencing, this manuscript: Amgen, Inc (Thousand Oaks, CA, USA) in the amount of less than USD 10,000; Eli Lilly and Company (Indianapolis, IN, USA) in the amount of less than USD 10,000; Graftys (Aix-en-Provence, France) in the amount of less than USD 10,000; Kuros Biosurgery AG (Zürich, Switzerland) in the amount of less than USD 10,000; Bone Therapeutics (Brussels, Belgium) in the amount of less than USD 10,000; and Merck & Co, Inc (Kenilworth, NJ, USA) in the amount of USD 100,001 to USD 1,000,000. One of the authors (DEP) lists the following relevant financial activities outside of this work and/or any other relationships or activities that readers could perceive to have influenced, or that give the appearance of potentially influencing, this manuscript: Mako Surgical Corp (Davie, FL, USA) in the amount of less than USD 10,001 to USD 100,000; and Stryker Corporation (Kalamazoo, MI, USA) in the amount of less than USD 10,000. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research1 editors and board members are on file with the publication and can be viewed on request. Each author certifies that his or her institution approved or waived approval for the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research. This work was performed at the Hospital for Special Surgery, New York, NY, USA. W. W. Schairer, J. M. Lane, D. E. Padgett, A. S. McLawhorn (&) Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 E 70th Street, New York, NY 10021, USA e-mail: mclawhorna@hss.edu D. A. Halsey Department of Orthopaedic Surgery, University of Vermont Medical College, South Burlington, VT, USA R. Iorio NYU Langone Medical Center, Hospital for Joint Diseases, New York, NY, USA 123 Clin Orthop Relat Res DOI 10.1007/s11999-016-4868-2 Clinical Orthopaedics and Related Research® A Publication of The Association of Bone and Joint Surgeons®