Major components of bone in subcapital and trochanteric fractures. A comparative study

Green Nanotechnologies for Responsible Manufacturing

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Influence of acetabular and femoral version on fractures of the femoral neck

BACKGROUND

Fractures through the proximal femur are broadly grouped into intertrochanteric fractures and intracapsular fractures. It is not clear why a patient may sustain an intertrochanteric fracture as compared with an intracapsular fracture. There is an established relationship between relative hip retroversion and the development of osteoarthritis. We postulate retroversion also may be a risk factor for having intracapsular fractures develop.

QUESTIONS/PURPOSES

We looked specifically at the geometry of the hip to analyze the possibility of a relationship between acetabular version, femoral version, and Mckibbin's instability index and fracture type.

PATIENTS AND METHODS

We recruited 40 patients with fractures of the femoral neck for the study. There were 15 men and 25 women with a mean age of 80 years (range, 57-92 years). There were 14 intertrochanteric fractures and 26 intracapsular fractures. After treating their fracture, the contralateral hip was scanned in a CT scanner and assessed by two independent observers to establish the acetabular and femoral version.

RESULTS

We found no correlation between proximal femoral fracture type and the contralateral femoral version, femoral neck length, acetabular version, or Mckibbin's instability index or between fracture type and age or gender.

CONCLUSIONS

There appears to be no correlation between proximal femoral fracture type and acetabular or femoral version.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Biocompatibility evaluation of a novel hydroxyapatite-polymer coating for medical implants (in vitro tests)

Nanocomposites consisting of hydroxyapatite (HA) and a sodium maleate copolymer (maleic polyelectrolyte), synthesized by hydrothermal method and deposited on titanium substrates by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique were tested for the biological properties. Coating bioanalysis was carried out by triple staining of actin, microtubules and nuclei followed by immunofluorescence microscopy. Within 24 h cells that occupied the biomaterial surface displayed the morphology and cytoskeleton pattern similar to the controls. Cells grown on nanocomposite coated surfaces had a higher proliferation rate than their counterparts grown on Ti coated with HA alone, indicating that maleic polyelectrolyte improved surface bio-adhesive characteristics. The capacity to induce cell attachment, spreading and proliferation demonstrated the potential of Ti coated with HA-polymer nanocomposites to be used as scaffolds in dental or orthopedic implantology.

Characterization of bone mineral composition in the proximal tibia of cynomolgus monkeys: effect of ovariectomy and nandrolone decanoate treatment

Life postmenopausal women, ovariectomized cynomolgus monkeys (Macaca fascicularis) experience accelerated loss of bone mass. Treatment of ovariectomized monkeys with nandrolone decanoate results in an increase in bone mass to levels comparable to those of intact animals. The changes in bone composition that occur with these treatments, however, are less well characterized. In the present study, we used synchrotron Fourier-transform infrared microspectroscopy (FT-IRM) and curve-fitting methods to monitor specific changes at cortical, subchondral, and trabecular bone regions in the proximal tibia. Four groups were studied: (1) sham-operated (sham); (2) ovariectomized and treated with placebo for 2 years (ovx); (3) ovx + nandrolone decanoate for 2 years (NAN); and (4) ovx + nandrolone decanoate beginning 1 year after ovx (dNAN). The results demonstrate that ovariectomy and nandrolone treatment did not affect the degree of mineralization as defined by the phosphate/protein ratio, but acid phosphate content (HPO(4)(2-)) in cortical and subchondral bone was increased by ovariectomy, suggesting this bone to be less mature due to increased remodeling that occurs after ovariectomy. In the subchondral and cortical bone regions, ovariectomized monkeys showed a lower total carbonate content (CO(3)(2-)/matrix ratio) than sham controls, specifically due to the decrease in labile carbonate content. In the trabecular region, no change of carbonate content was observed. Treatment with nandrolone decanoate was found to restore the loss in carbonate, where the resulting mineral had a larger quantity of type B carbonate. Finally, we correlated carbonate content with dual-energy X-ray absorptiometry measurements, and found a positive correlation between bone mineral density and type A carbonate in bone, which is stoichiometrically related to the amount of calcium in bone. Therefore, the results presented herein identify significant differences in bone chemistry after ovariectomy and nandrolone treatment, which may help explain previous findings that, although nandrolone decanoate treatment increased bone mass, it could not reverse the decrease in bone strength due to ovariectomy.

The influence of osteoarthritis on the pattern of proximal femoral fractures

The relationship between subcapital and trochanteric fractures and osteoarthritis was investigated to test the hypothesis that the presence of osteoarthritis would predetermine the site of the fracture. The authors reviewed 429 pelvic radiographs of patients with proximal femoral fractures. Osteoarthritis was found in 18 patients (4.2%). Sixteen patients followed the predicted fracture pattern of subcapital fracture and osteoarthritis of the other hip, or trochanteric fracture and osteoarthritis of the same hip. These results were statistically significant, supporting the hypothesis that patients with osteoarthritis of the hip who fall are likely to sustain a contralateral subcapital fracture or an ipsilateral trochanteric fracture.

Selective depression of metabolic activities in cortical osteoblasts at the site of femoral neck fractures

The aim of this investigation was to determine whether some metabolic defect might be related to the propensity of osteoporotic femoral necks to fracture acutely. To this end, the activities of two dehydrogenases of the glycolytic Embden-Meyerhof pathway, two of the pentose phosphate pathway, two mitochondrial enzymes, and alkaline phosphatase were measured in the cortical and in the trabecular osteoblasts. Comparison was made with such activities in iliac crest biopsies from patients with these fractures and from the equivalent femoral and iliac crest samples from patients with osteoarthritis of the hip, in biopsies from the iliac crests from seven patients with no bony abnormality, and in specimens from the fracture site of six traumatic fractures. The results showed a highly significant decrease in the activities of the two enzymes of the pentose phosphate pathway (p less than 0.001) in the cortical, but not in the trabecular, osteoblasts in the osteoporotic fractures. This could not be attributed to the trauma of acute fracture since it was not found in traumatic fractures. Other experimental evidence has indicated that a relationship may occur between depressed activity of these enzymes and a retardation of bone formation.

Lifetime fracture risk: an approach to hip fracture risk assessment based on bone mineral density and age

Hip fractures occur late in life following a substantial reduction in skeletal mass. If risk for such fractures could be predicted early, efforts to prevent excessive bone loss would be more successful and could be directed at the individuals most likely to be affected. With this objective in mind, we devised an approach to estimating the lifetime risk of a proximal femur fracture based on age and on current femoral bone mineral density, using population-based data from ongoing studies of osteoporosis and fractures among Rochester, Minnesota, women. Our calculations indicate that, at any given age, the lifetime risk of a proximal femur fracture rises as current bone density diminishes. At any given level of femoral bone density, lifetime risk rises with younger age and increasing life expectancy. While these trends seem robust, estimates of risk vary substantially with the assumptions that underlie the model. Consequently, these assumptions must be validated before our findings can be applied clinically to predict risk for individual patients.