Nondestructive determination of iliac crest cancellous bone strength by pQCT

The close relationship between apparent bone density and compressive strength is well established. In clinical situations, histomorphometry and determination of the compressive strength on bone biopsies are destructive methods and require two separate biopsies from each patient. The aim of this study was to evaluate whether volumetric bone density measured by peripheral quantitative computed tomography (pQCT) could be used as a nondestructive method for estimating trabecular bone strength of iliac crest bone biopsies, thereby allowing the same biopsy to be used for subsequent histomorphometry. Materials consisted of trabecular bone samples prepared from unilateral transiliac crest bone samples obtained at autopsy [total 95 specimens; 41 females (21-90 years) and 54 males (23-87 years)]. From these, the apparent density of the cancellous bone was evaluated by pQCT in a 1-mm-thick slice in the middle of the biopsy and also by ash density measurement. Bone strength was measured by compression test. A strong power relationship was found between density measured by pQCT and compressive strength (r = 0.93, p < 0.00001). Likewise, there was a strong power relationship between ash density and compressive strength (r = 0.97, p < 0.00001). A linear correlation was found between pQCT measurement and ash density (r = 0.98, p < 0.00001), indicating a very high accuracy for the pQCT measurement. In conclusion, pQCT provides a very good estimate of cancellous bone strength. This nondestructive assessment of strength of iliac crest bone biopsies thereby enables biomechanical information as well as histomorphometric measurements to be obtained from the same biopsy.