GENESIS II/ LEGION Total Knee System

Transcription

1 GENESIS II/ LEGION Total Knee System The GENESIS II/LEGION knee with the VERILAST technology The knee tested to simulate 30 years of wear performance

2 DISCLAIMER: Always speak to your doctor about the options that would be available to you, as well as the benefits and risks associated with each option. The information in this brochure is for general educational purposes only, and should not be construed as medical advice, or as statements relating to suitability of any implant for you, or for other persons. The GENESIS II/LEGION knee with VERILAST technology The first knee tested to simulate 30 years of wear performance Advances by the researchers at medical device maker Smith & Nephew have opened an exciting new chapter in high performance knee replacement surgery. The company has announced the introduction of a world first: VERILAST Technology knee replacement material tested to simulate 30 years of wear performance. VERILAST Technology lasts twice as long as knee replacements made with traditional materials. Knee replacement implants While you may have already discussed options for surgery with your orthopaedic surgeon, there is one point about total knee replacement that is worth repeating: the implants you will receive simply replace the diseased surfaces of your joint in order to help you get to a healthy, active lifestyle you had before knee pain limited your mobility. These surfaces are on the femoral (thigh bone) and tibial (shin bone) sides of your joint with the femoral side being made from metal and the tibial side being made from a dense plastic (see images 1, 2 and 3). Implant wear A common issue with knee replacements is what surgeons refer to as wear. As the surfaces of the implant rub together, tiny fragments of plastic and metal material wear off. This effect not unlike what takes place inside a car s engine accounts for one reason why knee implants can fail, and why a patient may undergo repeat surgery years after the original procedure. The consensus of scientific literature is that knee replacements are expected to last between 10 and 15 years before wear becomes an issue.

3 VERILAST technology Fortunately, not all implants are the same. Smith & Nephew introduced VERILAST Technology a pairing of materials that is shown in laboratory testing to double the wear performance of the company s GENESIS II/LEGION knee replacement. It is the combination of Smith & Nephew s award-winning OXINIUM metal alloy and a crosslinked plastic component (XLPE). The knee replacement technology that uses advanced, lowfriction surfaces for both sides of the knee joint. OXINIUM + XLPE = VERILAST Cross-linked plastic While the standard plastic components used in knee replacement have sufficient wear properties for knee replacement, most companies have introduced a more dense, lower-friction plastic called cross-linked polyethylene. It is created by altering the plastic molecules to create a tighter weave of particles at the microscopic level, thus reducing the amount of wear experienced when the metal component moves across it. You could think of it as having a higher thread count, like fabric. OXINIUM material If you receive an implant made with VERILAST Technology, the thigh bone side will be made from OXINIUM material a patented metal alloy that Smith & Nephew spent more than a decade developing, and has been used globally on knee implant procedures. The curved, black component in the illustrations to the right are made with OXINIUM material. Nearly all other knee implants are made from a metal called cobalt chrome. While cobalt chrome has proven to be an excellent bearing surface for knee replacements, OXINIUM material is a generational leap forward. It is a metal alloy (made primarily of zirconium) that undergoes a heating process that transforms the surface into a hard, smooth ceramic yet it retains all of the strength of the underlying metal. 1 A patient s guide: The GENESIS II/LEGION knee with VERILAST Technology

4 OXINIUM material is light weight because it doesn t contain detectable amounts of nickel like cobalt chrome does, it s considered hypoallergenic and is safe for patients with metal allergy or metal sensitivity. Image 1 Image 2 Image 3 A knee joint with advanced osteoarthritis GENESIS II/LEGION primary knee implants with VERILAST Technology The implants are secured into place Why 45 million cycles? Based on scientific literature reviews, a person who undergoes knee replacement surgery at the relatively young age of 45 years old would subject the implant to between 36 and 44 million cycles over a 30-year period, depending on how active the person s lifestyle is. 1-7 Smith & Nephew chose the high end of this range 45 million cycles as the simulated 30-year mark. The typical age of a knee replacement patient is between 65 and 70 years old. How important is knee implant wear? Implant wear is very important. One scientific study found that in a group of knee implants that were revised after an average of 7 years of use, 44% of the cases were the result of plastic wear. 8 What other issues contribute to implant failure? Wear is only one reason why a knee implant may need to be replaced later in life. Listen carefully when your orthopaedic surgeon reviews other risks that can shorten the life of your new knee such as infection, excessive weight or high impact sports. The testing performed on the GENESIS II/LEGION knee made with VERILAST Technology simulated 30 years of actual use under typical conditions and does not account for these and other variables. 2

5 The unprecedented test Smith & Nephew performed nearly three continuous years of laboratory-based wear testing on its GENESIS II/LEGION knee made with VERILAST Technology, and used an internationally accepted protocol (developed at Leeds University in England). During those tests, the implants were subjected to 45 million cycles, or steps, on a high-tech wear simulator. That s equivalent to 30 years of an active adult s life under typical conditions. Each cycle loaded the knee implants with 265 kgs of pressure, or an industry standard of 3.2 times the typical body weight of a knee replacement patient (84 kgs). During the same test, a similar knee made from conventional materials cobalt chrome and standard plastic were submitted to wear testing, as well. The results are remarkable: 98% Wear Reduction: After 5 million cycles, the GENESIS II/LEGION knee with VERILAST Technology reduced 98% of the wear that was generated by the other, traditional implant materials (see Chart 1) 81% Wear Reduction: When the GENESIS II/LEGION knee with VERILAST Technology kept walking out to 45 million cycles, it still reduced 81% of the wear generated by the conventional material knee implant that was stopped after the first 5 million cycles (see Chart 2) 160 Mean volumetric wear (mm 3 ) Conventional 3 years 98% years Chart 1: Comparison of the plastic wear of a conventional knee and VERILAST Technology after simulating 3 years of use. 3 A patient s guide: The GENESIS II/LEGION knee with VERILAST Technology

6 160 Mean volumetric wear (mm 3 ) % Conventional 3 years 30 years Chart 2: Comparison of the plastic wear of a conventional knee after simulating 3 years of use and 30 simulated years of VERILAST Technology. Based on laboratory wear-simulation testing, the GENESIS II/LEGION Primary Knee System with VERILAST Technology is expected to provide wear performance sufficient for 30 years of actual use under typical conditions. The results of laboratory wear-simulation testing have not been proven to predict actual joint durability and performance in people. A reduction in wear alone may not result in improved joint durability and performance because other factors, such as bone structure, can affect joint durability and performance and cause medical conditions that may result in the need for additional surgery. These other factors were not studied as part of the testing. There are potential risks with knee replacement surgery such as loosening, fracture, dislocation, wear and infection that may result in the need for additional surgery. Do not perform high-impact activities such as running and jumping unless your surgeon tells you the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if you do not follow your surgeon s limitations on activity level. Early failure can happen if you do not guard your knee joint from overloading due to activity level, failure to control body weight or accidents such as falls. Knee replacement surgery is intended to relieve knee pain and improve knee functions. Talk to your surgeon to determine what treatment may be best for you. 4

7 References: 1. Goldsmith AA et al., Comparative study of the activity of the total hip arthroplasty patients and normal subjects. J Arthrop, (16)5: , Morbidity and mortality weekly report, 55(40): , October 13, ( mmwrhtml/mm5540a2.htm?s_cid=mm5540a2_e. Accessed on October 30, 2009). 3. Gioe TJ et al., Knee Arthroplasty in the young patient Survival in a community registry. Clin Orthop Relat Res, 464:83-87, Wallbridge N and Dowson D. The walking activity of patients with artificial hip joints. Eng Med 11:95, Wimmer M A et al., Joint motion and daily activity profile of total knee patients in comparison with the ISO knee wear simulator. Paper 0159, 48th ORS, Huddleston J I et al., How often do patients with high-flex total knee arthroplasty use high flexion?, Clin Orthop Relat Res, 467: , Naal F D et al., How active are patients undergoing total joint arthroplasty? A systematic review, Clin Orthop Relat Res, DOI /s , published online: 28 October Sharkey et al., Why are total knee arthroplasties failing today? Clin Orthop Relat Res, 404:7-13, For more information ask your orthopaedic surgeon, or visit: Smith & Nephew (Pty) Ltd 30 The Boulevard, Westend Office Park Westville, 3629 Republic of South Africa Tel: Fax: Trademark of Smith & Nephew Smith & Nephew March 2015