Successful Reconstruction of Natural Femoral Anteversion using a Shortened Femoral Stem in Total Hip Arthroplasty Surgery

Ultrashort anatomic metaphyseal-fitting cementless femoral stems were developed in order to reduce post-operative risks in Total hip arthroplasty surgery; risks such as thigh pain, periprosthetic fractures and stress yielding. As far as guidelines when inserting the femoral component, recommendations are to restore the offset and the “natural anteversion” of the femur in normal femoral anatomy. Yet there is limited data on the topic of successful restoration of native femoral anteversion in Total Hip Arthroplasty surgery. In our study we researched this topic using a “Minimax” prosthesis, which is a new generation shortened anatomical femoral stem made by Medacta.

Methods:
We included patients between the ages of 18-90 who went through elective total hip arthroplasty in the years 2018-2020 with this specific prosthesis. Patients underwent a low dose Computed Tomography (CT) in one of the routine follow-ups. Femoral anteversion was measured by one fellowship trained musculoskeletal radiologist specialist with twenty years of experience. We assessed the position and anteversion of the femoral component in comparison to the unoperated side. In addition, we assessed patient satisfaction and functional levels six month after surgery using the Harris Hip Score (HHP) and the Oxford Hip Score (OHS).

Results:
Between the years 2018 and 2020 a total of nineteen individuals were recruited. There was a total of nine men and ten women between the ages 27-83 at an average age of 59.2 years. We found no statistically significant difference in femoral anteversion when comparing the operated hip to the native hip. When analyzing the HHS and OHS questionaries we found clinical improvement when comparing preoperative scores to six-month post-operative scores.

Discussion:
The new generation shortened anatomical femoral stem made by Medacta was able to reproduce natural femoral anteversion and succeed in improving patients functioning and lifestyle. Future prospective large scale comparison trials are needed in order to further investigate this topic.