Content area
Full text
1. Introduction
Until now bone mineral density (BMD) is a standard used widely in medical practice to assess bone quality [1] and indirectly its strength. Still the result of BMD does not give information about bone structure [2] and cannot alone contribute in strength assessment [3, 4]. The importance of microarchitecture structure factors has been recently emphasized [5, 6].
These reports are mainly concerned with examinations of osteoporosis as well as biomechanical tests of bone strength in order to combine the degree of osteoporosis with bone strength [7–9]. These studies have been conducted at several different levels: on whole bones or samples cut out from them [10, 11], or even on particular osteons or trabeculae [12, 13], using both human and animal bones.
Apart from BMD and microarchitecture structure factors the fractal dimension [14] is used to estimate bone strength. This dimension was used by other authors to evaluate bone structure and BMD [15–19]. However, there were no reports on fractal dimension and volume parameters with strength and comparison with BMD.
The main aim of the work was to assess the value of selected structural parameters in description of strength of bone. In our study we focused on volume of layers and fractal dimension of layers, BMD and their correlation with bone strength.
We also wanted to find out which parameter would be better for description of bone strength.
2. Material and Methods
2.1. Specimen
We tested trabecular bone samples. Samples were collected from 42 human femoral heads, the mean age of the patients was 73 yr (range 50–91). These specimens were obtained during hip arthroplasty. The study was approved by the Local Ethic Committee.
First, slices were cut out from the base of the head at 8,5 mm thickness, perpendicular to the axis of the neck of the bone (Figure 1(a)). Then, from the central region of the slices (Figure 1(b)), the samples were cut out in the shape of a cylinder, 10 mm diameter and 8,5 mm height (Figure 1(c)).
[figures omitted; refer to PDF]
2.2. MicroCT Technique
MicroCT investigation of cylindrical samples was done on microCT scanner (MicroCT 80 scanner, Scanco-Medical AG, Switzerland) with resolutions of 36 microns and with basic parameters: 70 kV, 114 μA, 500 projections/180°, and 300 ms integration time. Thus we obtained around...