Navigated modular short-stem total hip arthroplasty by a less invasive technique

Abstract

Since November 2004 we have been using a modular short-stem hip prosthesis with a less invasive anterolateral approach in 154 cases. The modified Watson-Jones [1] approach allows the insertion of the hip prosthesis without detaching muscles. The modularity of the prosthesis offers the choice of different degrees of anteversion and CCD angles to restore hip biomechanics. This is simulated by the navigation system. We evaluated primary stability, ease of minimally invasive implantation and restoration of biomechanics. We found good functional results and a low complication rate, without any dislocation. The navigation helps to insert the cup more precisely and to restore the center of rotation, leg length and offset. It suggests the best choice of modular neck to use and helps to predict and influence the safe range of motion. The emphasis is placed on the description of the surgical steps.