Femoral fixation in primary total hip arthroplasty.

We have presented the major advantages of using femoral components that have porous coating over the entire stemmed portion and have a cylindrical distal shape. The advantages of a stem with these design features also are reflected in the changing pattern of hip implant usage. A decade ago, the most frequently used porous-coated implants were those designed predominantly for metaphyseal fixation. At that time, the only commercially available, extensively porous-coated stem with a cylindrical distal stem shape was the anatomic medullary locking (AML) prosthesis. Currently, the most commonly used porous-coated prosthesis is the extensively porous-coated AML. Virtually all implant manufacturers now make a stem with design features similar to the AML. While concerns about stress shielding and prosthesis removal remain, they have not proven to be a clinical problem in our experience. We have used these stems in all of our primary total hip arthroplasties for 20 years and continue to do so.