Question

The figure show an example of a nail-plate combination used to fix an intertrochanteric 2250 N force is applied to the femoral head, in the direction shown with respect to vertical. 15° 135 1 cm 4 cm

Determine the magnitude of the component of the applied force that could cause the femoral head fragment to “telescope” (slide along the nail).

Where does the maximum moment (and thus the most likely point of failure) occur in the implant? Estimate the approximate magnitude of the maximum moment using the given scale.

Answer 1

Question 1:

1. 135 degree plates are utilized here.

2. Thus angle is easier to insert in the desired central portion of female head.

3. Higher angle devices create less astress riser in the sub trochantric region.

Question 2:

1. Maximum movement occur in sub trochandric region.

Thus makes failure of implants.