Heavy reading in heavy metal Unraveling the mystery of hip tissue in metal on metal total hip arthroplasty

In this thesis, we investigated the use of computer tomography (CT) for the screening of patients with a metal-on-metal (MoM) hip prosthesis in two patient cohorts. With a self-established CT grading scale, we have shown that CT is a reliable method for the diagnosis of postoperative pathological capsular reactions and also a strong predictor for the need for revision.
Revision of a hip prosthesis may be complicated by bone loss around the cup of a prosthesis. To determine the appropriate surgical technique it would be helpful when the pre-operative bone mineral density around the prosthesis could be measured using the previously made CT-scan. We showed that bone mineral density can be successfully measured with the aid of internal references of fat and muscle tissue.
The interpretation of CT scans of MoM prostheses is complicated by metal artifacts. Recently Orthopedic Metal Artefact Reduction (O-MAR) software became available to reduce these metal artifacts. We quantified the positive effect of O-MAR on metal artifacts in a self-designed hip phantom.
The enhanced CT image quality will lead to a wider use of CT in orthopedics when metal implants are involved, and contribute to a better treatment.