More aggravated osteoporosis in lateral trochanter compared to femoral neck with age: Contributing age difference between inter-trochanteric and femoral neck fractures in elderly patients

Abstract 

In the medical literature, elderly patients with inter-trochanteric fractures are considered older than those with femoral neck fractures, but the reason for this age-related difference remains unclear. Inconsistent bone mass re-distribution with age in both regions was hypothesised and the change in bone mineral density (BMD) was studied. This study aims to investigate another possible pathomechanism of reducing bone strength in the proximal femur with increasing age. The findings might help in developing a better method for preventing osteoporotic hip fractures.

Patients and methods

In the BMD study, 400 consecutive female patients were divided into eight groups, comprising 50 individuals each. Except for the first group (16–20 years), all other groups were divided by 10-year age increments up to 90 years. Relative BMD change with age in different regions in each group was compared.

Results

The BMD ratio of the lateral trochanter to the neck gradually reduced with age, whereas that of the medial trochanter to the neck gradually increased. The comparisons were statistically significant (p<0.001 in both cases).

Conclusion

One important predisposing factor to affect patients with inter-trochanteric fractures older than those with femoral neck fractures may be that the BMD is further lowered in the lateral trochanter compared to the femoral neck with age. It may be caused by lack of compressive loads in the lateral trochanter in daily activity. All devices which may increase bone mass in the lateral trochanter, theoretically, may be helpful in lowering the incidence of hip fractures.

Keywords: Osteoporosis, Trochanter, Femoral neck, Bone densitometry