The gender solutions Natural-Knee flex system and future directions.

The morphology of the distal femur varies. Whether or not the variability falls strictly along gender lines, a better fit to the distal femur can be obtained without intraoperative compromises by making available both a narrow and a wider medial-lateral/anterior-posterior aspect ratio. In our 1-year outcomes of the first 360 patients who received the Zimmer Gender Solutions Natural-Knee Flex System, mean flexion was 131 degrees (10 degrees better than mean flexion with the earlier Natural-Knee I and II systems), and the lateral release rate decreased to 2%. We no longer need to downsize during surgery to achieve good fit in femurs-in female patients typically-with narrower medial-lateral/anterior-posterior aspect ratios.