Removing large diameter acetabular cups with the Explant Acetabular Cup Removal System: A technique to maintain the centre of rotation

Removal of bonded, uncemented acetabular cups is challenging for orthopaedic surgeons, as excessive bone loss or acetabular fracture can compromise the fixation of the revision component.¹ To prevent complications, the Explant Acetabular Cup Removal System (Zimmer, Warsaw, IN, USA) uses a pivot head to find the centre of rotation of the acetabulum, guiding a cutting blade precisely around its curvature. In large acetabular cups, such as those used in metal-on-metal hip replacements, the pivot head used to fix the centre of rotation is too small.

We describe a technique using the femoral head from the old prosthesis and the foil from a suture pack to centre the device and maintain an accurate centre of rotation.

Technique

The old femoral head is removed from the stem. A foil suture pack is folded in half and wound around the tip of the explant device (Figure 1, inset). The femoral head is then placed onto the tip covered in foil and impacted to secure it. The device is then perfectly centred within the acetabular cup and will function with accuracy (Figure 1).

Figure 1.

The suture is packet folded in half and then wound around the explant device (top left), allowing the use of the original femoral head to centre the device perfectly for removal of the acetabular cup.

Discussion

This technique is an effective and cheap way of fixing the centre of rotation when removing large diameter acetabular cups. It prevents the need for expensive loan equipment, using readily available materials in the operating theatre to maintain accuracy using the device in question.