Prevalence of osteolysis after simultaneous bilateral fixed- and mobile-bearing total knee arthroplasties in young patients.

This study aimed to evaluate the clinical and radiographic results and to document the prevalence of osteolysis associated with fixed-bearing (anatomic modular knee) and mobile-bearing (low contact stress) total knee arthroplasties (TKAs) in 61 patients younger than 55 years who had bilateral simultaneous primary TKAs. Forty-five patients were female and 16 patients were male. The mean age of the patients was 48.3 years (range, 34-55 years). The mean postoperative Knee Society knee and functional score were similar in both groups (91 and 90 points and 85 and 86 points, respectively). Three knees (5%) in each group were revised for wear of the tibial bearing, and 1 knee (2%) in the mobile-bearing TKA was revised for dislocation of the meniscal bearing. Osteolysis was identified in both radiographs and computed tomography scans in 6 knees (10%) in the anatomic-modular-knee group and 4 knees (7%) in the low-contact-stress group.