This article presents our experience with the use of antibiotic-impregnated calcium sulfate in the management of comminuted open fractures with a bony defect caused by combat-related blast injuries and high-energy wounds. Calcium sulfate was used 19 times in 15 patients (17 fractures) as a bone graft substitute and a carrier for antibiotics. The anatomic sites of the graft were as follows: 6 calcanei, 1 midfoot, 1 metatarsal, 5 tibiae, 3 femorae, and 1 humerus. The average number of procedures prior to grafting was 6.2 (range, 2-10; median, 6) with grafting performed at an average 28 days after injury (range, 9-194 days; median, 14 days). Average radiographic follow-up of 12 fractures not requiring repeat grafting or amputation was 8.5 months (range 1-19 months; median, 7 months), and all of these fractures demonstrated clinical and radiographic evidence of fracture healing and consolidation. Four patients subsequently underwent 5 transtibial amputations: 2 for persistent infection, 1 when the patient changed his mind against limb salvage acutely, and 2 for severe neurogenic pain. Including the 2 amputations for persistent infection, 4 patients (22.2%) required further surgical management of infection. Three patients (17.6%) subsequently developed heterotopic ossification at the graft site, which required surgical excision. Antibiotic-impregnated calcium sulfate is effective in treating severe, contaminated open fractures by reducing infection and assisting with fracture union.

Methods of determining distance covered in migration are discussed. "Two approaches for doing so are simply to ask movers how far they moved or to infer distance from localities of origin and destination. The former has been used in Health Interview Surveys, and the latter is applied to Current Population Surveys; both are national surveys conducted by the U.S. Census Bureau. The two approaches appear to produce consistent results and offer ways of increasing comparability of data and research findings on geographical mobility."

Age stands out as an important factor in multiple moves over a relatively short period of time. In addition, in the NHIS data whites show a higher tendency to be multiple movers than do blacks. It was also found that persons defined as interstate migrants moved more often than either intrastate migrants or local movers, but it is impossible to conclude anything more definitive about that relationship. In conclusion, mobility defined as a move rather than as a mover is clearly higher than estimates derived from five-year census data or the CPS, which only use the idea of a mover. On the whole, though, over three-year periods most persons do not move at all or they move and then return. Of those who do change residence, the majority move only once. By far the bulk of moves is accounted for by a relatively small segment of Americans. Of 34,000 moves reported in the NHIS, more than one-half were made by a small number of persons--4,400--who not only constituted scarcely one-fourth of all movers but were less than 1 out of every 11 Americans.

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Current Population Survey (CPS) data from the U.S. Bureau of the Census quite clearly document continued population redistribution away from SMSAs to nonmetropolitan areas in the United States in the second half of the 1970s. Also, despite popular and some professional allegations of a return of population to cities from suburban rings-which would herald another dramatic migration turnaround during the 1970s CPS data reveal even heavier migration away from central cities to both suburbs and nonmetropolitan areas than in earlier years. Suburban rings are continuing to gain and central cities are continuing to lose population as a result of migration patterns. Decline in population growth rates in the suburban sector is clearly associated with lowered levels of natural increase not to a decline in net immigration. Overall, from a strictly demographic perspective, the data reveal no evidence of a "return-to-the-city" trend.