How Long Do You Want Your Knee Implant to Last?
Just like the surfaces of your natural knee joint, friction created when the surfaces of a knee implant rub together can cause these surfaces to wear down over time. This type of implant wear is a leading cause of knee replacement failure.
Conventional wisdom indicates that most knee implants should be expected to last 10 to 15 years before implant wear becomes an issue. At Smith & Nephew, we've always thought we could do better. And since today's more active knee patients are having surgery younger and living longer, we knew we had to do better.1
Enter VERILAST◊ Knee Technology - a remarkable combination of advanced, low-friction materials that addresses implant wear on both surfaces of the implant: the award-winning OXINIUM◊ Oxidized Zirconium, a ceramicised metal alloy for the femoral side (thigh bone), and a highly "cross-linked" plastic for the tibial side (shin bone). When these two surfaces work together in the joint, they do amazing things:
- In rigorous lab testing, Smith & Nephew's LEGION◊ CR Knee made with exclusive VERILAST technology was subjected to 45 million cycles, or simulated steps. That's equal to around 30 years of physical activity.2
- The data showed that after 5 million cycles, the LEGION CR Knee made with VERILAST technology showed 98% less wear than did the same knee made using traditional implant materials. And when the LEGION CR knee with VERILAST technology kept "walking" out to 45 million cycles, it was again compared to the traditional knee's 5 million cycle data. Even with 40 million more cycles, the LEGION knee with VERILAST Technology showed 81% less wear.2-8
So while we cannot say we've eliminated implant failure due to wear, we believe our 20 years of dedicated research is paying off for patients who want to rediscover their active lives.
Important Testing Note
VERILAST knee wear testing and results apply only to the VERILAST LEGION CR Primary Knee System only. Extended lab-testing for other VERILAST knee systems have not been performed. 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.
Important Safety Notes
Individual results of joint replacement vary. Implants are intended to relieve knee pain and improve function, but may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, wear and infection that may result in the need for additional surgery. Patients should not perform high impact activities such as running and jumping unless their surgeon tells them that the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if a surgeon's limitations on activity level are not followed.
1 Elena Losina, Ph.D., co-director, Orthopaedic and Arthritis Center for Outcomes Research, Brigham and Womenï¿½s Hospital, Boston; William J. Robb III, M.D., chairman, Department of Orthopaedic Surgery, NorthShore University Health System, Evanston, Ill; Feb. 10, 2012, presentation, American Academy of Orthopaedic Surgeons, annual meeting, San Francisco.
2 Testing concluded at 45 million cycles. ISO 14243-3 defines test completion at 5 million cycles.
3 Goldsmith AA et al., "Comparative study of the activity of the total hip arthroplasty patients and normal subjects". J Arthrop, (16)5:613-619, 2001.
4 Morbidity and mortality weekly report, 55(40):1089-1092, October 13, 2006.(http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5540a2.htm?s_cid=mm5540a2_e. Accessed on October 30, 2009).
5 Gioe TJ et al., "Knee Arthroplasty in the young patient - Survival in a community registry". Clin Orthop Relat Res, 464:83-87, 2007.
6 Wallbridge N and Dowson D. "The walking activity of patients with artificial hip joints". Eng Med 11:95, 1982
7 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, 2002.
8 Huddleston J I et al., "How often do patients with high-flex total knee arthroplasty use high flexion?",Clin Orthop Relat Res, 467:1898-1906, 2009.
9 Naal F D et al., "How active are patients undergoing total joint arthroplasty? A systematic review", Clin Orthop Relat Res, DOI 10.1007/s11999-009-1135-9, published online: 28 October 2009.
10 R. Papannagari, G. Hines, J. Sprague and M. Morrison, "Long-term wear performance of an advanced bearing knee technology," ISTA, Dubai, UAE, Oct 6-9, 2010.
The information listed on this site is for informational and educational purposes and is not meant as medical advice. Every patient's case is unique and each patient should follow his or her doctor's specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation.