- Discussion:
- goal: ream close to endosteal cortex, which has strongest cancellous bone;
- enter medullary canal w/ curet, & ensure that there are no perforations;
- this is esp important w/ osteoporotic bone;
- to enlarge medullary canal of diaphysis, use of medullary nail reamers may be necessary;
- if rasp is used for this purpose, risk of femoral fracture is high; the rasp will act as a wedge to split the femur;
- similarly, it is important to determine that the diameter of the stem is the same as the diameter of the medullary reamer;
- for press fit, it is advisable to ream a canal 0.5 to 1.0 mm > stem;
- in general, for cement fixation of the stem, the extent of reaming is such that most of the cancellous bone is removed and the cement is fixed to cortical bone;
- the first reamer is introduced by hand to ensure that the back cut is large enough and that the canal is open;
- this reamer should not touch the bone around the back cut;
- reaming should stop once the cortex is felt;
- previous templating will give a fairly clear idea of the expected size
- if the reamer begins to touch cortex at a much smaller size than expected, then the reamer is in a varus orientation;
- the back cut should then be enlarged and the canal rereamed