Malalignment

The assessment of the alignment may be possible on plane x-rays but sometimes requires the use of a CT scan. The problem often lies in the orientation of the socket component. The difficult decision for the patient and the surgeon alike if malalignment has been identified but the components are well fixed, is to proceed to removal of the existing implants and the placement of the new ones in correct alignment. This is clearly major surgery and not without risk both locally to the tissues and bones of the hip joint and also to the general medical well being of the patient.

Sometimes however, it may be possible to change the bearing surface of a modular acetabular component with satisfactory correction of the dislocations and yet with surgery which is much less traumatic than a full blown revision. The more modern components have bearing surfaces or liners available that can effectitvely “change” the alignment of the socket side or provide a protection against dislocation. There are also some liners available for the acetabular component, that “capture” the femoral ball and stop it from dislocating. However, all of these have some downsides which is why they are not routinely used for first time hip replacement surgery in all cases.