An individualized approach for the implantation of a humeral prosthesis with the proper retroversion in fractures

We applied a new methodology in 7 patients with a fracture of the upper hum eral head that required hemiarthroplasty, to implant a humeral prosthesis w ith an individualized posterior version. Our goal was to determine preopera tively the distance from the posterior edge of the bicipital groove where t he lateral fin of the humeral prosthesis should sit, in order to reproduce the individual retroversion during surgery. Using three computed tomography scan sections of the upper humerus and image processing software, we estim ated the above-mentioned distance in the sound humerus and implanted the pr osthesis in each patient accordingly. The differences in retroversion betwe en the left and right humeral heads permit a better approximation to normal applying this methodology than inserting the prosthesis in a standard retr oversion.