MRI Comparison of Periprosthetic Structures Around Zirconium Knee Prostheses and Cobalt Chrome Prostheses

OBJECTIVE. The purpose of our study was to compare reviewer confidence and interobserver agreement in the evaluation of MR images of periprosthetic structures around zirconium total knee prostheses and cobalt chrome prostheses.MATERIALS AND METHODS. Three board-certified radiologists blinded to prosthesis type used identical MRI protocols to independently evaluate 21 total knee prostheses: 14 zirconium prostheses and seven cobalt chrome prostheses. The radiologists evaluated the following eight parameters: integrity of the medial and lateral collateral ligaments, the quadriceps and the patellar tendons, presence of a joint effusion, and for evidence of periprosthetic osseous signal abnormality around each of the three components. The reviewers gave their degree of confidence in evaluating each of the findings on a five-point scale, 0 being no confidence and 4 being high confidence in the finding. The degree of confidence was used as the vehicle for comparing the two groups of patients.RESULTS. The confide...