Clinical and Radiographic Comparison of Oxidized Zirconium and Cobalt Chrome Femoral Components of a Single Design Primary Total Knee Arthroplasty: Is the Cost Difference Justified Based on Patient Outcomes?

A review of 120 consecutive total knee arthroplasty patient records was made comparing oxidized zirconium with traditional cobalt chrome alloy femoral components and assessing the clinical and radiographic outcomes of each. The direct hospital implant cost for each of these implant systems was obtained and assessed in the context of any difference in patient Knee Society Scores, knee flexion, pain, probability of metal allergy, and radiographic signs of pending implant failures. At an average of 5.6-year followup (1–11-year range in both groups), the data showed no clinical or radiological variance between the two groups, while the hospital direct implant cost with the oxidized zirconium femoral component was $1900 higher than the cobalt chrome implants. Considering the cost difference between the implants and the lack of a difference in outcomes at an average of 5-6 years of followup, this paper brings into question the ability to justify the use of oxidized zirconium femoral components based solely on improved patient outcomes.