Tips and Tricks relating to the Stryker Exeter X3 RimFit Socket | Which Medical Device

The first and probably the most important step is to ensure adequate exposure of the acetabulum. The rim cutter at times is difficult to use in a poorly exposed acetabulum, for example in a large muscular male patient allowing acetabular reamers above 54 mm or a small socket in an obese female. One needs to protect the posterior capsule, in standard posterior approach, either using a self-retainer retracting the capsule safely or a charnley pin in the ischial tuberosity.
Once the acetabulum is reamed to expose the cancellous surface, a rimfit socket / cutter is selected, usually 2 mm less than the last acetabular reamer used. A trial socket is placed in the acetabulum in the desired position of 45° of inclination and 25° of anteversion. This allows identifying any large circumferential osteophytes – which can now be removed conventionally using osteotome. This would then not impede positioning of the rim cutter.
The green hemispherical guide acts as centraliser and it would be useful to choose a size smaller than the desired rimfit cutter to place it in the base of the reamed acetabulum. The alignment rod is then fitted to the handle next to the tissue protector. It can be a clumsy construct to introduce the handle with the very mobile alignment rod. So, the power drill (battery operated or ones with hose using compressed air) is connected once the handle is positioned with the alignment rod vertical and at 25° of anteversion. The drill is checked for the correct direction of revolution – clockwise, prior to fitting it to the handle.
Taking care once again to protect the soft tissues, the handle is held at the junction of the alignment rod in one hand and the power tool in the other. The initial easy revolution will be slowed as the rim fit cutter approaches the bony rim. With gentle ‘orthopaedic’ pressure the reamer is advanced, guided by the alignment rod and the hemispherical guide, to create a uniform bony seat for the angled rimfit flange. The bony or labral debris are removed using a nibbler. In a retroverted or slightly more anteverted acetabulum, there may be areas of undercut rim, i.e posterior or anterior respectively. This has to be borne in mind whilst positioning the definitive implant. Use of a quick setting cement such as CMW 2, with a narrow working time should be sufficient, as the position remains unchanged with the flange sitting comfortably. An acetabular pressuriser is unnecessary if the cup is used with the flange.
The PMMA beads guarantee a uniform cement mantle, but some if not all can be removed easily with a pair of artery clips/kochers, if working in a shallow acetabulum, prepared with multiple drill holes.
Understandably, if one decides not to use the rim-cutter, in a less exposed acetabulum, the rimfit cup can still be used by trimming the flange either totally or in parts depending on the defects in the bony rim.
Those surgeons who find it difficult to accept the principle of rim fit flange, can still use this cup without the flange as it provides a highly crosslinked option with a large diameter (32 mm) head, even with the use of a 48 mm socket.