Abstract 37

The Contribution of Cancellous Bone Structure and Turnover to Human Femoral Fragility Fractures

H Tsangari^1,4, DM Findlay^2,4, JS Kuliwaba^1,3,4 and NL Fazzalari^1,3,4

¹Div of Tissue Path, IMVS, Adelaide, ²Dept of Ortho & Trauma, ³Dept of Path, Uni of Adelaide and ⁴Hanson Institute, Adelaide

Fragility fractures result from reductions in the amount, quality and architecture of bone. However, morphometric investigations have been limited to skeletal sites, which do not fracture, eg. iliac crest bone. Therefore, we have examined bone structure and indices of bone turnover in femoral bone from fractured neck of femur (#NOF) and control individuals. Intertrochanteric bone cores were obtained from 11 female autopsy cases (mean age 76.0±6.3 [SD] yrs) with no evidence of skeletal pathology, and from 15 female patients (mean age 80.7±6.9 yrs) undergoing surgery for a sub-capital femoral fracture. Bone specimens were processed undecalcified into resin and histomorphometry was performed. Interestingly, group comparisons revealed no difference between the female controls and #NOFs at the bone structural level. The static index of bone formation, osteoid surface, was positively correlated with age in the female #NOF group, whereas eroded surface was not age-dependent. In both cohorts, the mean and variance of the bone turnover parameters were greatly increased compared with younger controls. Although eroded and osteoid surfaces were positively correlated in both the female #NOF and control groups (r=0.52; p<0.05 and r=0.88; p<0.001, respectively), regression slopes were significantly different (p<0.001), suggesting that remodelling may be different in the #NOF group. Although we have previously found differences between #NOF patients and control individuals in the expression of RANK, RANKL and IL-6 mRNA in bone from this skeletal site, these differences did not relate to histomorphometric measures. Ongoing studies will seek to further investigate properties of bone that might contribute to fragility fractures.

Return to Listing of 2004 Abstracts
View Listing of 2005 Abstracts