Your web browser is out of date. For the best experience on Zimmer websites please upgrade to the latest version of Internet Explorer, Chrome, or Firefox.

Zimmer, Inc.

Gender Solutions® Natural Knee® Flex

Product Description

Since 1985, the Natural-Knee System has been used successfully to treat over 500,000 patients.

The Natural-Knee System philosophy is based on Cruciate Retaining (CR) and Cruciate Sacrificing (CS).

The Gender Solutions Natural Knee Flex system is the third generation of evolution for the system and  builds on the long clinical lineage the Natural-Knee system while incorporating the Zimmer Gender Solutions and High Flex Technologies.

 

The Gender Solutions Natural Knee Flex System is designed for use with Natural Knee II Tibia Baseplates. These asymmetrical tibial baseplates provide optimal coverage of the tibial plateau, creating stability without impingement due to overhang, and ultimately replicates natural anatomy.

 

The Ultracongruent articular surface provides posterior stabilization without bone sacrifice. A deepener trochlear groove prevents excessive load on the patellar component while allowing natural range of motion (ROM).

 

The asymmetric condyles of the femurs facilitates natural posterior femoral rollback. The lateral condyle moves significantly more posterior than the medial condyle with increasing knee flexion.

 

The surgery using the Gender Solutions Natural-Knee Flex System creates a true resurfacing by referencing the least involved portion of the femoral condyle, the least- involved portion of the tibial plateau, and the thickest portion of the medial facet of the patella, restoring kinematics and the anatomic joint line.

 

The Csti™ (Cancellous-Structured Titanium) Porous Coated Implant Interface provides bone in growth.

 

Posterior Referencing femoral resection results in matched flexion and extension gaps, which help with natural roll back, natural ROM and a potential for reduced polyethylene wear.

 

The Gender Solutions Natural-Knee Flex system is available with fixed and also rotating platform.

 

Long-term clinical results confirm that the Natural-Knee System’s design considerations result in improved motion and stability, and promote normal alignment and stable fixation of the implant.

 

The mean Modified Hospital for Special Surgery knee score improved from 59.0 +/- 13.2 preoperatively to 97.8 +/- 4.7 postoperatively at 10-to-14 years follow-up[5]

References

  1. Hofmann, Aaron A. Evanich, J.David. Ferguson, Ryan P. Camargo, Marcello P.  Ten to 14 year clinical followup of the cementless Natural-Knee System. CORR No.388, July, 2001.
  2. 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.
  3. 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.
  4. 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.
  5. Urabe K, Miura H, Kuwano T, et al. Comparison between the shape of resected femoral sections and femoral prostheses used in total knee arthroplasty in Japanese patients. J Knee Surg. 2003;16(1):27-33.
  6. 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.
  7. Jensen, R.E., Collier, J.P., Mayor, M.D., Surprenant, V.A., “The Role of Polyethylene Uniformity and Patient Characteristics in the Wear of Tibial Knee Components,” Implant Retrieval Symposium of the Society for Biomaterials, St. Charles, Illinois, September, 1992.
  8. Conditt M, Stein J, Noble P: Backside Polyethylene Wear in Modular Tibial Inserts.  46th Annual Meeting Orthopaedic Research Society 2000: 197.
  9. Yao JQ, Laurent MP, Johnson TS, Mimnaugh K, Blakemore D, et al.: Backside wear of conventional and high crosslinked UHMWPE tibial inserts as tested in knee wear simulator.  Society for Biomaterials 29th Annual Meeting Transactions, 609, 2003.
  10. Haman JD, et al. Tibial post damage in TKA’s is associated with tibial plateau damage. 49th Annual Meeting of Orthopaedic Research Society 2003. Paper #0006.
  11. Hill PF, Williams VV, Iwaki H, et al: Tibiofemoral movement 2: the loaded and unloaded living knee studied by MRI. J Bone Joint Surg Br 82:1196, 2000.
  12. Komistek, R.D., Mahfouz, M.R., Bertin, K. et al, In vivo determination of PCR NexGen TKA:  A multicenter anaylsis.
  13. Bertin, K., Komistek, R.D., Dennis D., et al, In vivo determination of posterior femoral rollback for subjects having a NexGen posterior cruciate retaining Total knee arthroplasty, J. Arthroplasty 17.8 (2002) 1040-1048.
  14. Richard D. Komistek, PhD; Mohamed R. Mahfouz, PhD; Kim C. Bertin, M.D.; Aaron Rosenberg, M.D.; and William Kennedy, M.D.;  In Vivo Determination of Total Knee Arthroplasty Kinematics.  JOA Vol. 23 No. 1 2008
  15. Data on File at Zimmer
  16. Engh, GA, et al. Polyethylene wear of metal-backed tibial components in total and unicompartmental knee prostheses.  J Bone Joint Surg: 1992: 74B:9.
  17. Peters PC, et al. Osteolysis after Total Knee Arthroplasty without Cement. J Bone Joint Surg: 1992: 74A: 874.
  18. Sharkey PF, Hozack WJ, Rothman RH, Shastri S, Jacoby SM: Why are total knee arthroplasties failing today?  Clin Ortho. 2002: 404: 7-13.
  19. Conditt M, Stein J, Noble P: Backside Polyethylene Wear in Modular Tibial Inserts.  46th Annual Meeting Orthopaedic Research Society 2000: 197.
  20. Yao JQ, Laurent MP, Johnson TS, Mimnaugh K, Blakemore D, et al.: Backside wear of conventional and high crosslinked UHMWPE tibial inserts as tested in knee wear simulator.  Society for Biomaterials 29th Annual Meeting Transactions, 609, 2003.
  21. Haman JD, et al. Tibial post damage in TKA’s is associated with tibial plateau damage. 49th Annual Meeting of Orthopaedic Research Society 2003. Paper #0006.
  22. Greer, Keith W., et al. The Effects of Raw Material, Irradiation Dose, and Irradiation Source on Crosslinking of UHMWPE. Journal of ASTM International, Vol. 1 No. 1. Paper ID JAI11217. Jan. 2004
  23. Muratoglu, Orhun K. and William H. Harris. Identification and Quantification of Irradiation in UHMWPE through Trans-Vineylene Yield. Journal of Biomedical Materials Research, Vol. 56, Iss. 4:584-592. 2001
  24. Hofmann, Aaron, Bachus, Kent, Wyatt, Ronald.  Effect of the Tibial Cut on Subsidence Following Total Knee Arthroplasty. Clin Ortho. No.269, 1991.
  25. P.N Baker, F.M. Khaw, L.M. G. Kirk, C.N.A. Esler, P.J. Gregg; A randomised controlled trial of cemented versus cementless press-fit condylar total knee replacement. 15 year survivorship analysis.  JBJS Vol.89-B, No.12, December, 2007.
  26. Smith, Jeffrey R., Hofmann, Aaron A. Morphology Of The Proximal Tibia In The Arthritic Knee.
  27. Wevers, H.W., Simurda, M., Griffin, M., Tarrel, J.  Improved fit by asymmetric tibial prosthesis for total knee arthroplasty. Med. Eng. Phys. Vol.16 297-300. July 1994.
  28. Hofmann, Aaron, A., Tkach, Thomas, K., Evanich,; Christopher, J., Camargo, Marcelo, P.  Posterior Stabilization in Total Knee Arthroplasty With Use of an Ultracongruent Polyethylene Insert. JOA Vol. 15 No. 5. 2000.
  29. Hofmann, Aaron A. Posterior Stabilization Using An Ultracongruent Deep Dished Polyethylene Tibial Insert.
  30. Bobyn JD, Pilliar RM, Cameron HU, Weatherby GC.  The Optimum Pore Size for the Fixation of Porous-Surfaced Metal Implants by the Ingrowth of Bone.  Clin Orthop. 1980, 150:263-70.
  31. Hofmann, Aaron A. Evanich, J.David. Ferguson, Ryan P. Camargo, Marcello P.  Ten to 14 year clinical followup of the cementless Natural-Knee System. CORR No.388, July, 2001.
  32. Bloebaum, Roy. Rhodes, David. Rubman, Marc. Hofmann, Aaron. Bilateral Tibial Components of Different Cementless Designs and Materials. CORR No. 268 July, 1991
  33. Hofmann, Aaron A. Heithoff, Scott M. Camargo, Marcelo. Cementless total knee arthroplasty in Patients 50 Years or Younger. CORR Vol. 404 November, 2002
  34. Evanich, Christopher. Tkach, Thomas. Glinski, Slabine Von. Camargo, Marcelo. Hofmann, Aaron. 6 to 10 Year Experience Using Countersunk Metal-Backed Patellas. JOA VOl.12 No. 2 1997 
  35.  

Technology

Gender Solutions

High Flex Technologies

MIS Instruments

Highly Crosslinked Polyethylene

Congruent and ultracongruent articular surfaces

PSI

Related Products

Natural-Knee II

NexGen CR Flex- Compatibility

Product Evolution

 

  • 1985 October, Multi-center FDA Trial Natural-Knee I System
  • 1986 Natural-Knee I System introduction to US Market
  • 1990 Natural-Knee I System CoCr femoral components replace Ti femoral components
  • 1992 Ultracongruent tibial insert introduction
  • 1995 Launch of Natural-Knee II Primary and Revision system
  • 1997 Natural-Knee II Primary system receives PMA for cementless application
  • 1998 Constrained/Revision System Introduction
  • 2000 Introduction of the Rotating Platform of NK II in Europe
  • 2001 Natural-Knee II Durasul® Polyethylene Introduction
  • 2005 MIS Instrumentation
  • 2008 Gender Solutions Natural-Knee Flex System
  • 2008 Introduction of Prolong Highly Crosslinked Polyethylene option
  • 2010 Launch of the rotating Platform for the Gender Solution Natural-Knee Flex