Computed tomography in evaluation of revision hip arthroplasty outcomes

Background. This study aimed to assess contact between Recon Shell reinforcement cages used in revision hip arthroplasty and the bony base. Radiographic examinations were performed with the use of multi-energy computed tomography. Material and methods. We tentatively assess the fixation of Burch-Schneider reinforcement cages (Recon Shell made by Aesculap company) implanted in 10 patients, using two methods of evaluation. An analysis of dual energy CT scans enabled us to assess contact between the reinforcement cages and the bony base. Results. The two methods of evaluation produced different results. The evaluation method based on the division of the acetabular component into a weight-bearing zone and a non-weight-bearing zone (accounting for screw fixation) showed lack of support in the weight-bearing zone in 6 out of 10 cases and direct contact with the implant bed in only one case. The assessment of contact at anchorage holes of reinforcement cages fixed at primary procedures revealed no such support in only one case and the presence of direct contact in 5 cases. There was no correlation between the radiological outcomes and clinical results based on the Harris Hip Score. Conclusions. 1. Multi-energy computed tomography (MARS) is useful in evaluating results of revision hip allo-plasty. 2. The introduction of new imaging techniques for the evaluation of revision procedures demonstrates a need for new, unified methods of outcome assessment adjusted to the characteristics of a particular procedure.