- Technique of Femoral Neck Resection
- Femoral Component Offset
- Discussion:
- some pts have relative coxa vara and a very short distance between the lesser trochanter and the pelvis;
- others have a relative coxa valga and a large distance between the lesser trochanter and pelvis;
- select neck length to restore limb length and medial offset;
- if no shortening is present, then match center of head w/ the previously marked center of the acetabulum;
- if discrepancy exists, distance between femoral head center & acetabular center should be = to the previously measured limb length discrepancy;
- once neck length is selected, mark level of anticipated neck resection and measure the distance from the top of lesser trochanter to use as an intra operative reference;
- femoral head center frequently, but not always, corresponds w/ level of most superior aspect of greater trochanter;
- aligning marking for neck length determined by preoperative x-rays analysis w/ level of center of femoral head will set neck resection guide at appropriate level;
- incorrect neck resection level will be misleading w/ respect to apparent stem fit;
- too high resection: - resection level which is too high, would yeild excessive space medially in proximal canal, leading one to believe stem is to small;
- this would lead to varus stem position and high placement of head;
- too low resection:
- a resection level which is too low would result in impression that the stem is too large;
- causes incomplete seating, valgus stem position, and low head placement