Aims: To determine the effect of fracture and immobilization on bone mineral density and mechanical parameters in postemenopausal women with a distal radius fracture. Methods: Seventeen postmenopausal women with a distal radius fracture with an indication for conservative treatment were included in the study. pQCT measurements of the fractured forearm were performed 2–3 days after the fracture, at 10 days after the fracture and at cast removal (35–45 days). All measurements were performed at a 10mm, 20mm and 40mm distance from a reference line set at the most proximal part of the distal radioulnar joint. Cortical, trabecular and total density and SSIx, SSIy and SSIpolar parameters were assessed. Results: At the fractured forearm, a high statistically signiþcant decrease of cortical density was observed only between second measurement and cast removal at 10 and 20mm (p< 0.01) Total density was not signiþcantly altered and trabecular density at 10mm was signiþcantly increased at cast removal compared to values at the time of the fracture (p< 0.01). Subcortical bone density at 10mm was also signiþcantly decreased at cast removal (p< 0.01). At cast removal, SSIx and SSI-polar parameters of the fractured forearm were also statistically signiþcantly decreased at distances of 10 and 20mm (p< 0.05). Conclusions: Distal radius fractures in postmenopausal women treated conservatively lead to a decrease of cortical density and an increase of trabecular density near the fracture site. They also aggravate bending and torsional mechanical properties. The shift from cortical bone to trabecular bone seems to be time-dependent and is signiþcant at cast removal.

Aim. The purpose of this study was to examine the symmetry of the mechanical and tomographic properties of the rat femur and tibia, frequently used in biomedical research.

Materials-Methods. For this purpose both femora and tibiae of 43 Wistar rats underwent tomographic (pQCT) evaluation while both femora and tibiae of 40 further Wistar rats were subjected to destructive three-point bending testing. The age of the animals ranged between 3 and 12 months and all were males.

Results. While there was significant variation between the structural and the biomechanical properties between different animals the differences between the femora and the tibiae of the same animal were not statistically significantly different in the majority of animals.

Conclusion. We conclude that in healthy, sexually mature Wistar rats, in the first year of their life, there is no significant diversity in terms of tomographic and biomechanical properties of their opposing posterior limb long bones.

Purpose: The study was conducted to evaluate the effect of salmon calcitonin (sCT) on fracture healing in normal and hypogonadal male rats.

Material and Method: Fifty six male Wistar rats, aged 3 months, were undertaken hemiosteotomy of the distal femur shaft, of standard length and width. Half of the animals had been orchiectomised at the age of 2 months. The animals were divided in 8 groups, 7 rats each, as follow: A, a (normal, no sCT), B, b (normal+Sct), C,c(orchiectomised) and D,d (orchiectomised+Sct). Salmon calcitonin was administered immediately after the hemiosteotomy in a dose of 5IU/day subcutaneously. Groups A, a, C and c were given placebo. The animals of the groups a b, c, and d were killed at 2 weeks, while the animals of the groups A, B, C, and D were killed at 4 weeks. After the euthanasia, total bone density and cortical bone density of the callus was estimated by peripheral quantitative computed tomography (pQCT). Histological and histomorfometric parameters of the callus were estimated as well.

Results: The mean cortical bone density was 1221.93±13.82 (g/cm³±SE) for the group a, 1281.3±13.57 for b, 1221.41±18.24 for c, 1245±17.12 for d, 1173.45±34.14 for A, 1298.9±11 for B, 1280.78±13.68 for C, and 1279.4U19.2 for D. The mean total bone density was 843.95±13.69 (g/cm³±SE) for the group a, 859.84±26.46 for b, 892.27±25.3 fore, 861.37±10.88 for d, 818.97±32.5 for A, 926.39±19.6 for B, 888.31±24.19 for C, and 912.75±28.13 for D. Values of cortical bone density in group b and B were significantly greater than a and A, respectively (b> a, p=0.01 and B> A, p=0.002). Total bone density of the callus was statistically greater in group B than A (B> A, p=0.01). According to the histological and histomorphometric results, sCT increased the amount of cartilage (p=0.014) and the amount of woven bone (p=0.015) in group b compared to a, while osteoblasts number showed no difference between the two groups. Comparing groups c and d, sCT increased the amount of cartilage (p=0.036) and the amount of woven bone (p=0.0014) in group d compared to c, while decreased osteoblasts number in group d (p=0.03). In four weeks the amount of cartilage is significant greater in group D versus C (p=0.006), as well as the amount of woven bone (p=0.0004). The size of the callus is significant greater in group D compared to C as well (p=0.052).

Conclusion: It appears that salmon calcitonin administration improves significantly the parameters of callus bone density in normal rats and increases the amount of cartilaginous callus and woven bone both in normal and orchiectomised rats.