- Discussion:
- length & alignment are restored by use of femoral distractor in saggital plane, w/o need for fracture table;
- this permits hip and knee to be flexed on the table during nailing;
- the distractor may be particularly suited to poly trauma patients;
- disadvantage is that image intensification control is difficult to obtain in the lateral view;
- Proximal Schanz Screw:
- note that the proximal position of the pin must allow meduallary reaming and subsequent nailing to be carried out w/o interference;
- horizontal approach:
- 5 mm half pin is placed laterally into the lesser trochanter, w/ the half pin directed slightly upward (20 deg) from a posterior to anterior direction;
- pin is directed 90 deg to long axis of femur;
- vertical approach:
- proximal screw will pierce the rectus femoris muscle and often will also pierce the lateral edge of the sartorius;
- the femoral nerve, artery, and vein all lie medial to the screw;
- the femoral nerve is closest to the pin, lying 2.5 cm medial;
- the half pin should be inserted only after the nail is driven into the proximal fragment;
- the target is the proximal femur, just medial (and sl distal to) the lesser trochanter;
- Distal Schanz Screw:
- inserted just proximal to the condylar area in the anterior 1/3 of the femur;
- distally the Schanz screw must be removed before final nail insertion;
- pin is directed 90 deg to long axis of femur;
- Femoral Shaft Frx:
- pressure on the proximal fragment is exerted by the assistant to over-come tendency to extend w/ knee flexion;
- some manual support of frx is usually needed to control angulation;
- once the two Schanz screws are in place, the distractor is attached securely, and is threaded length adjustment is used to apply traction across the fracture site;
- typically mild apex anterior angulation of the fracture is controlled with manual pressure during reduction and nail insertion;
- alternatively, some surgeons will apply traction to the distractor only in cases in which the reduction cannot be accomplished w/ manual traction alone
Technique of Using the AO Femoral Distractor for Femoral IM Nailing