The ADVANCE® Medial-Pivot and Double-High Knees are designed to reproduce normal motion and anatomy. However, determining correct femoral size is difficult in men or women with a narrow distal femur.1 An implant that fits anterior/posterior may overhang medial/lateral.1 To prevent overhang, a smaller implant with a shorter anterior/posterior dimension may be utilized.2 Respectively, this can lead to soft tissue interference or mid-flexion instability due to excessive posterior condyle resection. 

ADVANCE STATURE® Femoral Components are designed to accommodate those male or female femora with a larger anterior/posterior dimension than medial/lateral. This helps ensure your patients will receive the best implant fit possible.

The Science of Total Knee Sizing
A new trend in the orthopaedic marketplace is total knee implant design based on gender differences. The idea is that men and women have different knee anatomy which requires different prosthetic design. It is believed there are three main differences between men and women that relate to design: women have a greater patellar track angle, women are more prone to overstuffing the front of the knee (when an implant is too thick for easy patella tracking), and the femur is narrower in women. There are several studies demonstrating an anatomic difference between men and women.2 However, few of these studies have taken the physical stature of the individuals into account. Those studies that have included other factors besides gender have found that patient stature, or height, is more of a determinant of implant needs than gender. Research has shown patellar track angle is not different due to gender, but is actually different due to the height of the individual.2 If a man and woman of equal height were measured, their patellar track angle would be the same. The patellar track of the ADVANCE STATURE® Knee has been implanted in both men and women for almost 10 years with excellent clinical success.3

Due to stature differences, it is common for a woman’s kneecap to be thinner than a man’s. Once again, studies have found this is not due to gender, but due to the differences in average height between men and women.4 Studies have shown increased height brings increased kneecap thickness. The differences are due to stature, not gender. The ADVANCE STATURE® knee component features a reduced overall height, which enables the patella to move more freely in smaller stature patients, regardless of gender.

It is also thought that women require a more contoured implant than a man to fit their narrow femur. However, it is not uncommon for men to have a narrow femur as well. Instead of a knee made just for females, the ADVANCE STATURE® Knee is made for men or women with a narrow femur. A very popular study showed that most implants were about 5mm too wide for females.2 For this reason, the ADVANCE STATURE® Knee has been reduced in width by 5mm to better fit the anatomy of males and females with a narrow femur.

The ADVANCE STATURE® femoral components are available for the ADVANCE® Medial-Pivot and Double-High knees.

References
1. Poilvache PL, Insall JN, Scuderi GR, Font-Rodriguez DE. Rotational landmarks and sizing of the distal femur in total knee arthroplasty. Clin Orthop Relat Res. 1996 Oct;(331):35-46.
2. K Hitt, et al. Anthropometric Measurements of the Human Knee: Correlation to the Sizing of Current Knee Arthroplasty Systems. JBJS 85:115-122 (2003).
3. Grelsamer et al. Men and women have similar Q angles: a clinical and trigonometric evaluation. J Bone Joint Surg Br.2005; 87-B: 1498-1501.
4. Pritchett JW. Patient preferences in knee prostheses. J Bone and Joint