title: Balance impairment is related to vertebral fracture rather than thoracic kyphosis in individuals with osteoporosis.
abstract: BACKGROUND
  Balance impairments have been identified in people with osteoporosis. Although an association between thoracic kyphosis and impaired balance has been reported, the specific role of vertebral fractures has not been considered. This study aimed to investigate the independent effects of osteoporotic vertebral fracture and thoracic kyphosis on balance characteristics in an osteoporotic population.
  
  
  METHODS
  Twenty-two individuals with osteoporosis were divided into groups with (n=10) and without (n=12) radiologically diagnosed fracture, and into groups with low (n=11) and high (n=11) thoracic kyphosis. Force-plate-derived balance parameters were recorded during three static standing tasks of 70-s duration. Balance measures were compared between fracture and kyphosis groups, and significant differences were further explored through subgroup analyses, to tease out the relationships between confounded independent variables (fracture and kyphosis) and balance measures.
  
  
  RESULTS
  In the anterior-posterior direction, the range and root mean square of shear forces (p=0.048 and p=0.032, respectively), and range of displacement of the centre of pressure (p=0.049) were greater in the fracture group. There were no differences between groups when comparison was based on the magnitude of thoracic kyphosis (all p>or=0.264). Analyses of subgroups supported these findings.
  
  
  CONCLUSIONS
  Vertebral fracture but not thoracic kyphosis is associated with impaired balance characteristics in the osteoporosis population. This finding has important implications for fracture prevention and conservative management regimes.
authors.affiliation: Centre for Health, Exercise and Sports Medicine, School of Physiotherapy, University of Melbourne, Victoria, 3010, Australia. a.greig@pgrad.unimelb.edu.au
authors.forename: A M
authors.initials: AM
authors.lastname: Greig
authors.forename: K L
authors.initials: KL
authors.lastname: Bennell
authors.forename: A M
authors.initials: AM
authors.lastname: Briggs
authors.forename: J D
authors.initials: JD
authors.lastname: Wark
authors.forename: P W
authors.initials: PW
authors.lastname: Hodges
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000150:complications / Q000503:physiopathology*; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000209:etiology / Q000503:physiopathology*; D015663:Osteoporosis, Postmenopausal / Q000150:complications / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*; D011312:Pressure; D012678:Sensation Disorders / Q000209:etiology / Q000503:physiopathology*; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000503:physiopathology*