Abstract
Objective
Recently, the short stem, taken on preservation of the femoral bone, is available on total hip arthroplasty and on femoral head prosthetic replacement. The handling of the short stem is easier than that of standard stem on implantation of femur. However, it would be difficult to make the direction of stem axis straight in femoral marrow cavity. Actually we experienced that the lateral cortical bone of the proximal femur was ground unevenly on rasping for implantation of the short stem. The aim of this study was to identify the efficacy of dulled rasp on implanting the short stem.
Subjects and Methods
We examined 42 hips of 39 patients who underwent the primary total hip arthroplasties with short stems in our institution from August 2011 to April 2014. Primary diseases were 28 osteoarthritides, 6 idiopathic osteonecrosises of the femoral heads and 5 others. We categorized N group as using standard rasp with sharpened blades and M group as using modified rasp with dulled blades named ‘Mild Rasp’, and analyzed with the statistical methods.
Results
The numbers of N group was 27 hips, consisting of 15 males and 12 females, with a mean age of 60.0 years and a mean body mass index (BMI) of 25.2. The mean time of operation was 149.9 minutes, and the mean amount of bleeding during surgery was 761.0 ml. The median of stem size was 13 (range, 5–17) and the mean declination angle from the femoral axis was 2.9. The numbers of M group was 15 hips, consisting of 4 males and 11 females, with a mean age of 63.1 years and a mean BMI of 27.3. The mean time of operation was 187.1 minutes, and the mean amount of bleeding during surgery was 875.7 ml. The median of stem size was 11 (range, 6–14) and the mean declination angle from the femoral axis was 1.3. The time of operation of the M group was significant longer than that of N group (p = 0.016). The declination angle from the femoral axis of the M group was significant smaller than that of N group (p = 0.005). The other parameters were not significant difference between M group and N group.
Discussion
When the short stems were implanted, it was reported to tend to be valgus position in femoral marrow cavity. We considered that it would be easy to grind the cortical bone of the proximal cavity by the rasp with sharpened blades. Therefor we used the rasp with dulled blades, the efficacy was indicated.
Conclusions
‘Mild Rasp’ would be useful for positioning more straight against the femoral axis on total hip arthroplasty.
