Absence of femoral cortical thickening in long-term bisphosphonate users: implications for atypical femur fractures.
The radiographs of patients on long term bisphosphonates with atypical femur fractures demonstrate markedly thick cortices at the site of the fracture. We conducted a prospective clinical study to determine if cortical thickening is increased in long term bisphosphonate users. We recruited 43 patients who had taken bisphosphonates for more than 5 years. A group of 45 healthy volunteers and 12 patients recently diagnosed with osteoporosis served as controls. We measured the cortical thickening as the ratio of femoral cortical thickness to diameter of the femur, and looked for cortical beaking. No difference in the cortical thickness ratio was observed between long term bisphosphonate users and osteoporotic controls (0.53 vs. 0.54, p=0.659). No cases of cortical beaking were seen and no increase in thigh pain was observed. The power of the study was 95% to detect a 10% difference in cortical thickness ratio. We conclude that long term bisphosphonate use does not produce a generalized increase in subtrochanteric femoral cortical thickening in the majority of patients.
Clinical and Investigative Orthopaedic Surgery Unit Intramural Research Program National Institute of Arthritis and Musculoskeletal and Skin Diseases 10 Center Drive, Bldg 10-CRC Room 4-2339 Bethesda, Maryland 20892, USA.
Foster
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Chen
Clinical and Investigative Orthopaedic Surgery Unit Intramural Research Program National Institute of Arthritis and Musculoskeletal and Skin Diseases 10 Center Drive, Bldg 10-CRC Room 4-2339 Bethesda, Maryland 20892, USA.
Zhong
Z
Wang
Clinical and Investigative Orthopaedic Surgery Unit Intramural Research Program National Institute of Arthritis and Musculoskeletal and Skin Diseases 10 Center Drive, Bldg 10-CRC Room 4-2339 Bethesda, Maryland 20892, USA. Electronic address: Timothy.bhattacharyya@nih.gov.
Timothy
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Bhattacharyya
D000368:Aged; D015331:Cohort Studies; D003710:Demography; D004164:Diphosphonates / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000188:drug therapy*; D005269:Femur / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D004164:Diphosphonates
Atypical femur fracture; Osteoporosis