The greater trochanter-head contact method: a cadaveric study with a new technique for the intraoperative control of rotation of femoral fractures.

OBJECTIVE

To describe a new method for femoral rotational alignment during intramedullary nail insertion using the profile of the greater trochanter and its relation to the femoral head.

METHODS

Radiologically, the line that represents the posterior border of the greater trochanter comes in contact with the femoral head contour during external rotation. The degree of rotation to achieve this contact was measured on both lower extremities of 15 whole fresh-frozen cadavers and seven dried human femora using a standard image intensifier. Computed tomography was used in the dried femora to assess the femoral anteversion angle, the length of the femoral neck, and the neck-shaft angle.

RESULTS

The side difference of the greater trochanter-head contact angle was 6° or less in 14 of 15 whole fresh-frozen cadavers. Regarding the dried human femora, this angle had a strong positive correlation with femoral neck anteversion angle (r = 0.9), whereas no statistically significant correlation could be detected with the neck length or the neck-shaft angle.

CONCLUSION

Our described method is simple to execute because it depends on a definite point of measurement. Furthermore, an angle is recorded for each extremity, which enables us to estimate the amount of the rotational difference. This method does not depend on special views, especially at the hip, but only a direct anteroposterior view with gradual internal rotation of the image intensifier.