- decide whether trochanteric osteotomy is required;
- it is essential to avoid a proximal femoral frx while extracting the stem;
- direct extraction of a femoral stem can be blocked by excessive cement or proximal bony overgrowth medial to the greater trochanter;
- this situation is worsened if the femoral stem is curved;
- surgical options are to remove the impedeing bone or cement which overly the lateral aspect of the stem (using high speed burr or osteotomes) or
to perform a trochanteric osteotomy;
- in either case, the lateral aspect of the stem shold be visualized prior to stem removal;
- Evaluate Distal Stem:
- note areas cement fragmentation;
- note on lateral view, where the femur begins to curve anteriorly;
- this will indicate how far distally cement chisels may pass;
- note amount of distal cement plugging;
- in the past 2 cm of distal plugging was recommended, often because the stems were end bearing;
- w/ more than 1-2 cm of cement, the procedure becomes much more complex;
- Visualization:
- arthroscopic lamp;
- windowing of the femur;
- trochanteric osteotomy:
- offers more complete access to proximal femur but comprimises stability provided greater trochanter to press fit system;
- flouroscopy:
- image intensification is extremely useful in avoiding bone damage, but it introduces increased risks of potential contamination of the surgical site