Intraoperative Measurement of Cementless Stem Anteversion

Anteversion of the femoral stem has become a matter of concern because retroverted or excessively anteverted stems might lead to an impingement and dislocation after total hip arthroplasty (THA). When using a cementless stem, it is difficult to adjust the stem anteversion because the geometry of the medullary canal of the proximal canal is different in each individual and cementless stems fit into the canal geometry. The anteversion of cementless stem is determined according to the anteversion of the proximal femur and surgeons cannot manipulate the version of cementless stem during press fitting of the stem. To prevent dislocation in hip with retroverted or excessively anteverted cementless stems, the concept of combined anteversion was developed. To obtain an optimal combined anteversion of femoral stem and acetabular cup, the stem anteversion should be measured first, and then the anteversion of the cup should be adjusted to calculate cup anteversion. The presence of knee osteoarthritis or tibia vara might alter the intraoperative measurement of a cementless stem. In this chapter, we discuss the accuracy of intraoperative measurement of stem version, and the effect of knee problems to the measurement.