Gender differentiated knee implant design is a new trend in Orthopaedics. Throughout the marketplace it is believed there are three main disparities between men and women relating to implant design:
Women have a greater trochlear groove angle (angle in their patellar track).
Women have a narrower distal femur (femur that is next to tibia when standing).
Women are more prone to anterior overstuffing (this is when an implant is too thick for patella to track easily).
Let’s review the differences to see if there is a stature difference or a gender difference. Several of the studies demonstrating an anatomic difference between men and women18 have not taken into account the physical stature of individuals. Those studies that have examined other factors besides gender have found that stature patient size is more of a determinant of implant needs than gender.
Dispelling Myth #1 “Women have a greater angle in their patellar track.”
Studies have shown the angle of patellar track (Q-angle) is not different due to gender, but is actually dependent on the height of the individual.
If a man and a woman of equal height were measured, their angle of patellar track (Q-angle) would be the same. Studies showing a gender
difference have not recognized that men are taller than women on average. They simply separate the sample by gender;
not stature. Other studies have shown that there is no difference in the structure of the trochlear grooves (patellar track) of male and
female fetuses and do not change in adulthood19, 20. Differences are due to stature.
Dispelling Myth #2 “Women have a narrower femur that is next to tibia when standing.”
One of the most referenced studies on gender sizing was performed by Kirby Hitt, MD. The study illustrates that most
knee components were 5mm too wide for the female population. However, this study did not examine other factors such
as patient height. The fact is some men need narrow implants as well. Differences are due to stature.
Dispelling Myth #3 “Women are more prone to have anterior overstuffing, which means the implant is too thick for patella to track easily.”
Due to stature differences, it is common for the female patella to be thinner than the male. Once again, studies have
found this is not due to gender, but are due to the differences in average height between men and women. Differences
are due to stature.
Solution: ADVANCE STATURE™
The ADVANCE STATURE™ femoral component provides the same tried and true features and the regular ADVANCE® implants with
some distinct sizing advantages for patients that need a narrower implant than the standard size. The components utilize the same
ADVANCE® patellar track angle that replicates the patellar track structure of both males and females21. Furthermore, the angle of patellar track (trochlear groove) has demonstrated excellent clinical results regardless of gender. The M/L dimension has been reduced by 5mm from the
standard ADVANCE® Knee. In addition, the front flange has been contoured to resist anterior overstuffing, which means the implant is too thick for patella to track easily.
Gender differentiated knee implant design is a new trend in Orthopaedics. Throughout the marketplace it is believed there are three main disparities between men and women relating to implant design:
Dispelling Myth #2 “Women have a narrower femur that is next to tibia when standing.”