Comparison of Early Results Between Bone-Conserving and Conventional High-Flexion Posterior-Stabilized Total Knee Arthroplasty

Background:The purpose of this study was to compare early clinical and radiographic results between bone-conserving and conventional high-flexion posterior-stabilized TKA.Methods: Two hundred and eighty-five patients (477 knees; mean age, 68.7 years) received a NexGen Legacy posterior-stabilized high-flex (NexGen LPS-Flex) TKA and 280 patients (472 knees; mean age, 70.1 years) received a Freedom posterior-stabilized prosthesis.The mean follow-up was 3.5 (range, 2 to 5 years) for each group.Results: Significantly less bone was resected from the distal femur (mean, 8.7 vs 7.8 mm), the posterior femoral condyles (mean, 11.5 vs 5.7 mm), and the intercondylar notch (mean, 11 vs 8.1 cm 3 ) in the Freedom TKA group compared with the NexGen LPS-Flex TKA group.There were no significant differences between the 2 groups at the latest follow-up regarding the Knee Society score (91 vs 93 points), the Western Ontario and McMaster Universities Osteoarthritis index (40 vs 38 points), knee range of motion (125 vs 128), the University of California, Los Angeles activity score (6.0 vs 6.2 points), and radiographic findings.The estimated survival rate was 99% (95% confidence interval, 92% to 100%) for the NexGen LPS-Flex TKA group and 99.6% (95% confidence interval, 93% to 100%) for the Freedom TKA group, with revision or aseptic loosening as the endpoint at 3.5 years after the operation.Conclusion: The present study suggests that the early clinical and radiographic results of the bone-conserving Freedom TKA were similar to those of the conventional NexGen LPS-Flex TKA.