FRI0578 Odontoid fractures in the elderly: an unknown osteoporotic fracture?

Background Current WHO definition of osteoporosis excludes cervical fractures. However, in atraumatic odontoid fractures, mainly reported by orthopedic surgeons, bone status has not been described yet [1]. Objectives To investigate bone status in elderly patients sustaining a low energy odontoid fracture. Methods We conducted a prospective study from January 2016 to January 2017 in patients >65 years old, hospitalized in Nice University hospital for low energy odontoid fracture. An evaluation of bone status was proposed within 3 months after fracture event. Evaluation included demographic data, clinical risk factors of osteoporosis, bone mineral density (BMD) at spine and hip and vertebral fracture assessment (VFA) by dual X-ray absorptiometry and serum analysis to detect secondary osteoporosis. Results 38 patients were hospitalized for odontoid fracture: 8 patients 3 months). 3 patients had previously received hormone replacement therapy, 1 received bisphosphonate for 5 years and 4 had calcium + vitamin D supplements. Lumbar spine mean T-score was -1.45 (±1.08), femoral neck: -2.37 (±0.040) and total hip: -1.99 (±0.6). VFA analysis revealed 4 unknown vertebral fractures. The table summarizes population bone status: 8 patients out of 10 fulfilled diagnostic criteria of osteoporosis, including 6 with previous fractures. 2 patients with T-score > -1.DS didn9t have hip BMD assessment because of bilateral hip replacement but had previous major osteoporotic fractures. No secondary osteoporosis was detected. Serum vitamin D concentration was Conclusions Our study reveals that odontoid fractures mainly occur in elderly osteoporotic patients after a low energy impact. Although WHO osteoporosis definition excludes cervical fractures, odontoid fracture may be considered as an osteoporotic fracture. Further studies are required to confirm these results. References Watanabe M, et al. Analysis of predisposing factors in elderly people with type II odontoid fracture. Spine J. 2014 Jun 1; 14(6):861–6. Disclosure of Interest None declared