Implant Design

A number of special considerations have to be taken into account during implant design. As visibility of the acetabulum during surgery is excellent, hardly any special considerations apply to insertion of acetabular cups, and most acetabular cup systems can be used with no particular problems. In our experience, press-fit acetabular cups from the Pinnacle system have proved to be best because of their versatility. The surgeon can choose between a variety of different highly crosslinked polyethylene, metal-on-metal and ceramic-on-ceramic components in sizes ranging from 28 to 36 mm. Thus, the ideal pair of components can be selected for each individual patient.

In femoral stem design, however, a number of fundamental considerations must be taken into account. In the minimally invasive surgical procedure we have developed, every effort is made to spare the muscles, especially the abductor muscles, as best as possible. It is possible, though more difficult, to insert a straight-stem implant using the minimally invasive approach. However, this would make little sense anyway since straight-stem implants often have to be inserted so far into the trochanter that they cause relevant damage to the hip abductor tendons. A stem with a lateral shoulder has two main advantages: it is much easier to insert and does not have to be inserted so far into the trochanter. Thus, no damage to the abductor tendons occurs.