2020 Volume 32 Issue 1 Pages 6-11
Background: This study aimed to evaluate the micromotion of the cementless short stem after total hip arthroplasty by using the finite element method and compared with postoperative X-ray images.
Patients and Methods: Ten patients who underwent total hip replacement with two types of cementless short stems in our department were included. The average age of the patients at the time of surgery was 63.4 years. Finite element models of the femur-stem complex were made by computed tomography images and were evaluated micromotion. The distributions of the micromotion were compared with postoperative X-ray images.
Results: The micromotion of 150 μm or more were concentrated proximally in nine of ten cases. These cases were observed radiolucent line with a reactive line of less than 1 mm in the postoperative X-ray image. This line was consistent with the area of the micromotion of 150 μm or more. The one of ten cases showed entirely micromotion of 150 μm or more in the stem.
Conclusion: The postoperative femoral bone reactions were consistent with the distribution of the micromotion between the cementless stem and the femur. The method of this study may be useful for predicting initial fixation of the stem.
