MINERAL METABOLISM OF FRACTURES OF THE TIBIA IN MAN STUDIED WITH EXTERNAL COUNTING OF Sr$sup 8$$sup 5$
A study was made of 51 adult patients with tibial fractures by external counting with scintillation detectors over the thighs, knees, and tibias during a 14-day period after intravenous injection of 25 to 50 mu c Sr/sup 85/. The pattern of activity curves recorded over the fractured leg compared to those recorded over the control leg varied significantly with the age of the fracture (2 days to 9 yr). Increased uptake of Sr/sup 85/ was observed in all cases. The activity ratio fracture/control tibia obtained 14 days after injection rose during the 1st months after fracture to reach a peak value 6 to 8 months after fracture. The mean 14-day fracture/ control ratios obtained 5 to 10 months after fracture was 15.5 plus or minus 7.2; then it dropped. Even 6 to 9 yr after fracture the counting rate over the fracture was higher than that over the intact tibia. No differences in activity uptake were observed between normally healing fractures and fractures showing delayed or nonunion. Activity curves obtained over the thigh, knee, and tibia of the fractured and intact legs 1 to l4 days after injection of Sr/sup 85/ could be simulated on the basis of a 2-compartment model for the kinetics of Sr in the body. Based on this kinetic analysis the externally recorded Sr/sup 85/ activity values may be interpreted as follows: The activity ratios fractured/intact leg obtained during early intervals after injection are mainly related to differences in the size of the exchangeable mineral spaces under the detector. The 14-day activity ratio of 2 anatomically comparable locations may be used as a relative index of the difference in the accretion rate (rate of irreversible deposition of bone mineral) in these locations, but is somewhat lower than the absolute dfference in the accretion rate. The bone salt laid down in the fracture callus is derived from the body fluids. The accretion rate in the fracture region is increased within a week of the fracture. It rapidly increases during the first months after fracture to reach a peak value at 6 to 8 months after fracture. The accretion rate in the entire fractured leg is increased some months after fracture. The traumatic osteopenia is caused by increased resorption and not by decreased accretion. (H.H.D.)
- Research Organization:
- Univ. of Lund, Sweden
- NSA Number:
- NSA-17-005678
- OSTI ID:
- 4739778
- Journal Information:
- Acta Orthopaed. Scand., Suppl., Vol. Vol: 52; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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