ORIGINAL ARTICLE Association between timing of zoledronic acid infusion and hip fracture healing C. Colón-Emeric & L. Nordsletten & S. Olson & N. Major & S. Boonen & P. Haentjens & P. Mesenbrink & J. Magaziner & J. Adachi & K. W. Lyles & L. Hyldstrup & C. Bucci-Rechtweg & C. Recknor & for the HORIZON Recurrent Fracture Trial Received: 8 July 2010 / Accepted: 5 October 2010 # International Osteoporosis Foundation and National Osteoporosis Foundation 2010 Abstract Summary Patients in the Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly (HORIZON) Recurrent Fracture Trial were assessed for evidence of delayed hip fracture healing. No association was observed between zoledronic acid (ZOL) and delayed healing. We conclude that ZOL has no clinically evident effect on fracture healing, even when the drug is infused in the immediate postoperative period. Introduction Intravenous zoledronic acid 5 mg (ZOL) given after a hip fracture reduces secondary fracture rates and mortality. It has been postulated that bisphosphonates may affect healing if given soon after a fracture. We sought to determine whether the timing of ZOL infusion affected the risk of delayed hip fracture healing. Methods In the HORIZON Recurrent Fracture Trial, patients were randomized within 90 days of a low-trauma hip fracture to receive either once-yearly ZOL (n =1,065) or placebo (n =1,062). Clinical symptoms of delayed hip fracture healing were sought at randomization, 6 months and 12 months after fracture; if present, a central adjudi- cation committee blinded to treatment assignment reviewed This study is supported by Novartis Pharma AG. C. Colón-Emeric : S. Olson : K. W. Lyles Duke University Medical Center and the Geriatrics Research Education and Clinical Center, Veterans Affairs Medical Center, Durham, NC, USA L. Nordsletten Ullevål University Hospital, Oslo, Norway N. Major Hospital of the University of Pennsylvania, Philadelphia, PA, USA S. Boonen Division of Gerontology and Geriatrics, Leuven University, Leuven, Belgium P. Haentjens Centre for Outcomes Research and Laboratory for Experimental Surgery, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium P. Mesenbrink : C. Bucci-Rechtweg Novartis Pharmaceuticals, East Hanover, NJ, USA J. Magaziner The University of Maryland, Baltimore, MD, USA J. Adachi McMaster University, Hamilton, ON, Canada L. Hyldstrup Hvidovre Hospital, Hvidovre, Denmark C. Recknor United Osteoporosis Centers, Gainesville, GA, USA C. Colón-Emeric (*) Duke University Medical Center and the Durham VA GRECC, 508 Fulton St. GRECC 182, Durham, NC 27705, USA e-mail: colon001@mc.duke.edu Osteoporos Int DOI 10.1007/s00198-010-1473-1