Zimmer® Prolong™ Highly Crosslinked Polyethylene

Why Prolong Highly Crosslinked Polyethylene…

Prolong Highly Crosslinked Polyethylene represents a significant advance in wear reduction.  Prolong polyethylene’s proven resistance to wear provides a promising solution for TKA patients, especially today’s more active, physically-demanding patient.

…Because Polyethylene Can Wear.

While TKA has proven successful, tibial insert wear and damage are often cited as primary causes for an estimated 63,000 revision knee surgeries each year.1,2,3,4  One recent study identified polyethylene wear as the most common cause for knee revisions.5   In this study, 44% of knees revised more than two years after the index arthroplasty were directly attributed to polyethylene wear.

The Prolong Polyethylene Solution

Prolong polyethylene is specifically designed to reduce wear and delamination.  This includes enhancements to a number of wear factors:

  1. Reduced topside wear6
  2. Resistance to oxidative degradation9
  3. Reduced backside wear8
  4. Improved resistance to articular subsurface and Posterior Stabilized (PS) spine/post delamination, pitting, and cracking1,7
Prolong Highly Crosslinked Polyethylene Wear

Wear Rates

In vitro wear simulator testing demonstrated an 81% reduction in total volumetric wear of CR articular surface components and a 78% reduction in total volumetric wear in PS articular surface components compared to conventional polyethylene.  The results of in vitro wear tests have not been shown to correlate with clinical wear mechanisms.

Prolong Highly Crosslinked Wear Rates

Start of Delamination in Laboratory Test Samples

In head-to-head testing specifically designed to result in early onset of delamination, conventional polyethylene inserts repeatedly showed signs of delamination, as compared to Prolong polyethylene, which showed no evidence of delamination.

 

Start of Delamination Chart

Oxidation

Prolong Highly Crosslinked Polyethylene is formulated specifically to resist wear under the conditions found in knees and represents a significant scientific advancement in wear reduction.  In wear and damage mechanism studies, Prolong polyethylene consistently resisted oxidation and delamination, thereby decreasing surface wear and subsurface fatigue that can lead to delamination or pitting.9

Prolong Oxidation Chart

Backside Volumetric Wear Rates

In joint simulator testing, conventional polyethylene exhibited more backside wear compared to Prolong polyethylene.8,11

Backside Volumetric Wear Rate Chart

PS Post Fatigue Strength Test

Testing has shown that the Prolong polyethylene PS post is at least as strong as the conventional polyethylene post.

PS Post Fatigue Strength Chart


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References

  1. Data on file at Zimmer.
  2. Engh GA, et al. Polyethylene wear of metal-backed tibial components in total and Unicompartmental knee prostheses. J Bone Joint Surg: 1992: 74B:9.
  3. Peters PC, et al. Osteolysis after Total Knee Arthroplasty without Cement. J Bone Joint Surg: 1992: 74A: 874.
  4. Cadambi A, et al. Osteolysis of the Distal Femur after Total Knee Arthoplasty. J Arthroplasty: 1994: 9: 579
  5. Sharkey PF, Hozack WJ, Rothman RH, Shastri S, Jacoby SM: Why are total knee arthroplasties failing today? Clin Ortho. 2002: 404: 7-13.
  6. Laurent MP, et al.: High cycle wear of highly Crosslinked UHMWPE tibial articular surfaces evaluated in a knee wear simulator. Soc. Of Biomaterials 28th Annual Mtg Transactions, 712, 2002.
  7. Yao JQ, Gsell R, Laurent MP, Gilbertson LN, Swarts D, Blanchard CR, Crowninshield RD: Improved delamination resistance of melt-annealed electron-beam irradiated highly Crosslinked UHMWPE knee inserts. Society for Biomaterials 28th Annual Meeting Transactions, 60, 2002.
  8. 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.
  9. Gsell R, Yao JQ, Laurent MP, Crowinshield RD: Improved oxidation resistance of highly Crosslinked UHMWPE for total knee arthroplasty. Society for Biomaterials 27th Annual Meeting Transactions, 84, 2001.
  10. Maher SA, Furman BD, Wright TM: Reduced fracture toughness of enhanced cross-linked polyethylene is not associated with increased wear damage. Society for Biomaterials 28th Annual Meeting Transactions, 542, 2002.
  11. Crowninshield RD, Yao JQ, Wimmer MA, Jacobs JJ, Rosenberg AG, Blanchard CR: An Assessment of Polyethylene Backside Wear in a Modular Tibial Total Knee System. Data on file at Zimmer.
  12. Conditt M, Ismaily S, Paravic V, White J, Noble P: Quantitative Assessment of Backside Wear of Polyethylene Tibial Inserts. 48th Annual Meeting Orthopaedic Research Society 2002, 160.
  13. Conditt M, Stein J, Noble P: Backside Polyethylene Wear in Modular Tibial Inserts. 46th Annual Meeting Orthopaedic Research Society 2000: 197.
  14. Griffin FM, Scuderi GR, Gillis AM, et al. Osteolysis associated with cemented total knee arthroplasty. J Arthroplasty 1998: 13(5): 592-598.
  15. 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.
  16. Banks SA, Harman MK, Hodge WA: Mechanism of anterior impingement damage in total knee arthroplasty. J Bone Joint Surg. 2002: 84A: 37-42.
  17. Puloski SKT, McCalden RW, MacDonald SJ, Rorabeck CH, Bourne RB: Tibial post wear in posterior stabilized total knee arthroplasty. J Bone Joint Surg. 2001:83A: 390-397.