Zimmer® Gender Solutions™ NexGen® High-Flex Knee

Modified ML/AP Aspect Ratio

CT data documents distinctive shape differences in female and male distal femurs.12,13 Female femurs are:

  • More trapezoidal-shaped.

  • Narrower in the M/L dimension when compared to a male femur of the same A/P dimension
Modified ML/AP Aspect Ratio

When a traditional implant is placed onto a resected female knee:

  • The implant may overhang the bone at the distal, anterior, and posterior M/L interfaces, which may lead to soft-tissue irritation and affect soft-tissue
    balancing.1,3,4
  • The surgeon may be faced with intraoperative adjustments to compensate for the overhang.

Gender Solutions High-Flex Femoral Implants have been narrowed mediolaterally.

This allows surgeons to address the female population with unprecedented accuracy.
Modified ML/AP

Related Articles

Zimmer Gender Solutions NexGen High-Flex Knee Overview
Two Distinct Populations:  Women and Men
Anterior Flange Thickness
Increased Trochlear Groove Angle
Femoral Mapping—Applying the Science
Competitive Analysis

References

  1. Hitt K, Shurman IIJ, Greene K, et al. Anthropometric measurements of the human knee: correlation to the sizing of current knee arthroplasty systems. J Bone Joint Surg. 2003;85:155-122.
  2. Poilvache PL, Insall JN, Scuderi GR, Font-Rodriguez DE. Rotational landmarks and sizing of the distal femur in total knee arthroplasty, Clin Orthop. 1996;331:35-46.
  3. Vaidya SV, Ranawat CS, Aroojis A, Laud NS. Anthropometric measurements to design total knee prostheses for the Indian population. J Arthroplasty. 2000;15(1):79-85.
  4. Chin KR, Dalury DF, Zurakowski D, Scott RD. Intraoperative measurements of male and female distal femurs during primary total knee arthroplasty. J Knee Surg. 2002;15(4):213-214.
  5. Csintalan RP, Schulz MM, Woo J, McMahon PJ, Lee TQ, Gender Differences in Patellofemoral Joint Biomechanics, Clin Orthop. September, 2002; 402 :260-269.
  6. Aglietti P, Insall JN, Cerulli G. Patellar pain and incongruence. I: Measurements of incongruence. Clin Orthop. 1983;176:217-224.
  7. Hsu RWW, Himeno S, Coventry MB, Chao EYS. Normal axial alignment of the lower extremity and load bearing distribution at the knee, Clin Orthop . 1990;255:215-227.
  8. Woodland LH, Francis RS. Parameters and comparisons of the quadriceps angle of college-aged men and women in the supine and standing positions. American Journal of Sports Medicine. 1992;20:208-211.
  9. U.S.Department of Health and Human Services, Centers for Disease Control and Prevention, National Centerfor Health Statistics. 2003 National Hospital Discharge Survey, Advance Data No. 359. July 8, 2005; Table 8:14.
  10. U.S.Department of Health and Human Services, Centers for Disease Control and Prevention, National Centerfor Health Statistics. 2003 National Hospital Discharge Survey, Advance Data No. 359. July 8, 2005; Table 10:16.
  11. Hawker G, Wright J, Coyte P, et al., Differences between men and women in the rate of use of hip and knee arthroplasty, The New England Journal of Medicine. 342:1016-1022, 2000.
  12. Mahfouz M, Booth R Jr, Argenson, J, Merkl, BC, Abdel Fatah EE, Kuhn MJ. Analysis of variation of adult femora using sex specific statistical atlases. Presented at: Computer Methods in Biomechanics and Biomedical Engineering Conference; 2006.
  13. Data on file at Zimmer
  14. Scott NW. Pearls on avoidance and treatment of intraoperative and postoperative complications – exposure of the stiff knee. Presented at: American Association of Hip and Knee Surgeons, Knee Society Specialty Day; March 25, 2006.
  15. Bengs BC, Scott RD. The effect of patellar thickness on intraoperative knee flexion and patellar tracking in total knee arthroplasty. J Arthroplasty. 2006;21(5):650-655.