Science Fiction
Now, other knee implant manufacturers claim to have knees designed for women.
According to Stryker, the Triathlon Knee System is "designed with women in mind."§
According to Biomet, the Vanguard Knee System addresses gender issues because it "was engineered to fit the entire population, regardless of race, gender,or stature." ¶
According to DePuy, the PFC Sigma Rotating-Platform Knee is "a true innovation in knees for women."≠
According to Smith&Nephew, its "knee replacement systems have always been female friendly in their shapes and sizing."**
Science Fact
Saying it doesn't make it a fact.
These manufacturers can put whatever label they want on their knee implants. The fact is, all of these designs are based on combined averages of male and female anatomies. The Zimmer Gender Solutions™ Knee is the only knee system that is designed specifically for women.
Comparing the Facts
Although the M/L dimension of the Stryker Triathlon Knee is narrower than that of other Stryker knee systems, the Triathlon knee still doesn't address the issues associated with the anterior condyle thickness, the trochlear groove angle, and the M/L-to-A/P aspect ratio.
Biomet added sizes to the Vanguard Knee System. The system doesn't address the anterior condyle thickness, the trochlear groove angle, or the aspect ratio for larger sizes.
DePuy's PFC Sigma Rotating Platform Knee has a much thicker anterior condyle, a fixed trochlear groove angle, and one of the widest femoral components on the market.
Smith & Nephew's Genesis II Knee does not address any of the gender issues.
§Stryker Orthopaedics Web site. Available at:
http://www.stryker.com/jointreplacements/sites/triathlon/
¶Biomet Orthopedics. Vanguard Complete Knee System. 2006.
≠Davis M. Zimmer knee's feminine twist. June 5, 2006. The Street.com. Health Care. Available at: http://www.thestreet.com/pf/stocks/healthcare/10289580.html
** Letter to surgeons from Scott Flora, President, Orthopaedic Reconstruction, Smith & Nephew, Inc., July 12, 2006.
