The canal fill ratio as a factor influencing the aseptic loosening of the Müller-type cemented stem--preliminary report.

The Müller type cemented hip prosthesis, also called self-locking prosthesis, is one of the most extensively copied and utilized hip prostheses. Considering the implantation of the cemented stem, the author originally suggested achieving a press fit between the stem and endostal cortex by implanting a prosthesis of the largest possible size. Analyzing our group of patients who undergo aseptic stem revision, we try to quantify the term "press fit" by measuring the filling of the femoral canal by the metal stem, the so-called canal-fill ratio. Our preliminary results suggest that press-fit is achieved when the stem occupies more than 90% of the canal diameter in the anterior-posterior projection.