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With increasing frequency trauma surgeons are advocating early internal fixation in open fractures. The effect of the fixation devices on the infection rate in contaminated wounds remains a concern as our clinical experience in this area has been mixed. To study the effects of internal fixation on bone infections a 3.5-mm stainless steel screw was inserted into rabbit femurs and the wounds contaminated with Staphylococcus aureus. The controls had the screw hole drilled and taped but the screw was not inserted. Thirty of 49 rabbits receiving the screw subsequently became infected whereas 19 of 56 control animals developed an infection. The difference was significant at the 0.05 confidence level.

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The load transmitted through fresh fractures of the tarsometatarsus of adult chickens was varied by 40% more, or less, than the body weight to determine the effect of load-bearing on fracture healing. The healing fracture was examined for size and strength at 14 days, but no significant differences were detected in any group. The technique was sensitive enough to detect the differences between healing fractures at 7, 10 and 14 days. In this experiment load transmission was not found to be an important factor in fracture healing.

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We reviewed the records of 281 patients with myelodysplasia to ascertain the effect of hip dislocation on their ability to walk. There was no difference in the prevalence of myelodysplasia by gender. When adjusted for neurologic level and patient age, no statistical differences were found in the methods of locomotion between patients with hip dislocations and those without. Data (from this report and other published investigations) show that treatment for hip dislocation in myelodysplasia is unnecessary and fraught with many complications.

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A double-blind prospective study was done to assess the benefit of delaying closure of the wounds associated with open fractures. An additional double-blind study compared the effectiveness of clindamycin versus cefazolin for prophylactic antibiotic coverage. Quantitative cultures of the wounds were accomplished at the time of debridement and again at the time of closure if the wound was not closed initially. Almost half of the wounds were contaminated (46%) at the time of debridement, although the incidence of wound infection was low (6.5%). Gram-negative organisms resistant to the prophylactic antibiotic were recovered initially only eight times, but four of these (50%) became infected. The contaminating organisms in each case were present in high concentration (greater than 10(5) CFU/gm of tissue) at initial culture. The time of wound closure, cefazolin versus clindamycin, and internal fixation of the fracture were not followed by significant differences in the development of clinical infection in this series.

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The tibia from six-week old chickens that develop idiopathic scoliosis were studied with stress relaxation experiments and torsional strength testing. Most parameters observed did not show any significant differences between tibias obtained from chickens with scoliosis and tibias from the control birds; however, the rate of stress relaxation of the tibia from the birds with scoliosis was minimally increased over the controls. There were no significant differences noted in ultimate torsional strength, maximum angular deformity or modulae of torsional rigidity of the tibias from scoliotic chickens when compared to tibias from control chickens.

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Day-old White Leghorn cockerels were fed skim-milk-based diets containing 0, 2, 4, 8, or 16 ppm added copper as CuSO4 for 21 days. Lysyl oxidase was extracted from bone and tendon. The recovery of activity from the extracts was linearly correlated with dietary copper (r greater than 0.90). Tests of the mechanical properties of tendon and bone indicated that tendon viscoelasticity (as measured by stress--relaxation) may not be significantly influenced by copper, whereas the ultimate torsional strength of bone is markedly decreased when the dietary copper level is below 1 ppm. Furthermore the torsional fracture characteristics of bone from copper-deficient birds demonstrated a lack of plastic deformation prior to failure that was normally seen in bone from control birds. The change in the mechanical properties of bone from copper-deficient birds appeared to be related to a decrease in the amounts of dihydroxylysinonorleucine and other lysine-derived cross-linking amino acids in bone collagen. The data indicate that the requirement for optimal growth of chicks fed skim-milk-based diets is 6--8 ppm copper, however, the requirement for normal cross-link formation in bone is less than 2 ppm copper.

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This study examines biochemically the Type I collagen isolated from skin of chickens that develop idiopathic scoliosis. Previous studies indicate a defect in collagen exists in these chickens. Alpha 1 (I) and alpha 2 chains were separated by gel filtration and carboxymethyl cellulose column chromatography and were then subjected to the analytical techniques of sodium dodecyl sulfate gel electrophoresis, Staphylococcus aureus V8 protease digestion, cyanogen bromide peptide mapping and amino acid analyses. In all categories, the scoliotic alpha 1 (I) and alpha 2 chains were identical to alpha chains isolated from normal chickens. These data suggest that the altered properties of collagen solubility and connective tissue stress relaxation seen in these scoliotic chickens are not a manifestation of an altered primary structure of the alpha chains or post-translational modification affecting chromatographic elution profiles or electrophoretic migration patterns.

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The genetics of an inherited form of scoliosis in chickens was studied to estimate the number of genes involved, whether they are autosomal or sex-linked, their degree of dominance and penetrance, and the heritability of this trait in this population. Expression of scoliosis and in the progeny was analyzed by radiographs of birds 12 weeks of age or older. Crosses between an inbred line selected for scoliosis expression (incidence of scoliosis - 89 percent) and a highly inbred line displaying normal spinal development provided data for genetic analyses. The incidence of expression of scoliotic parent line implicates three major autosomal, recessive genes. The significantly higher incidence of severe scoliosis found in the homogametic male sex is ascribed to a sex-influenced, on the scoliosis trait rather than to sex-linkage. Variation of expression observed in the scoliotic line is attributed to incomplete penetrance of the major genes, additive effects of minor modifying genes, and primarily to environmental effects. Because of the similarities in the expression of this disease in chickens and humans, the inheritance pattern determined for chickens may provide useful insights into that operating for so-called adolescent idiopathic scoliosis in humans.

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Quantitative bacterial and fungal cultures carried out on 116 speciments of tissue debrided from traumatic orthopedic wounds yielded 118 bacterial and 8 fungal isolates. The organisms obtained reflected primarily the resident flora of the skin.

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The systematic examination of synovial fluid confirms the noninflammatory nature of degenerative joint disease, is diagnostic of gout, pseudogout, and septic arthritis, and will usually allow the identification of rheumatoid arthritis, systemic lupus erythematosus and Reiter's syndrome.

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Scintigraphy, using 99mTc diphosphonate, has the potential for diagnosing osteonecrosis before irreversible changes are visible in routine roentgenograms. If obtained within weeks of an avascular insult, a cold area will appear on scintiscan. However, months later, the revascularization and reparative processes of the dead bone produce a hot area on scintiscan.

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Scoliosis developed in 55 per cent of sexually mature birds (68 per cent of male and 46 per cent of female birds) in a highly inbred line of chickens originally produced from white Leghorns. The curve could first be detected at five to six weeks of age and progressed until spontaneous fusion of the thoracic vertebrae occurred. Studies of these chickens indicated that abnormalities of growth and development of the spine are not the primary cause of the scoliosis. Preliminary studies of the paravertebral musculature also indicated that simple muscle imbalance is not responsible for the curve. Initial studies of collagen extracted from the scoliotic line of chickens showed it to be more soluble than similar collagen extracted from white Leghorn controls.

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