Total Knee Replacement: More than 85% Last at Least 20 Years

What is the evidence for total knee arthroplasty in young patients?: a systematic review of the literature. Clin Orthop Relat Res. 2011 Feb;469(2):574-83. Keeney JA1, Eunice S, Pashos G, Wright RW, Clohisy JC.

TKA is commonly performed to treat advanced inflammatory and degenerative knee arthritis. With increasing use in younger patients, it is important to define the best practices to enhance clinical performance and implant longevity.
We systematically reviewed the literature to assess: (1) how TKAs perform in young patients; (2) whether the TKA is a durable procedure for young patients, and (3) what guidance the literature outlines for TKA in young patients.
We searched the literature between 1950 and 2009 for all studies reporting on TKAs for patients younger than 55 years that documented clinical and radiographic assessments with a minimum 2-year followup. Thirteen studies, reporting on 908 TKAs performed for 671 patients, met these criteria.
Mean Knee Society clinical and functional scores increased by 47 and 37 points, respectively. Implant survivorship was reported between 90.6% and 99% during the first decade and between 85% and 96.5% during the second decade of followup. The literature does not direct specific techniques for TKA for young patients.
TKA provides surgeon-measured clinical and functional improvements with a moderate increase in second-decade implant failures. Improvements in study design and reporting will be beneficial to guide decisions regarding implant selection and surgical technique.
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

My comments:

So according to the above review, it’s hard to say exactly how long a new knee will last, but data indicates somewhere between 90-99% last at least 10 years and 85-96.5% last at least 20 years.

As a physical therapist I can do a lot with a number of arthritic knees to lessen pain and increase strength and function. However, there is a point where even the best exercises cause more pain than they are worth. Once a patient starts curtailing their activity to avoid knee pain they begin a downward spiral of lost overall fitness combined with overworking their other leg, which then becomes arthritic and weaker as well. I’ve had some patients who would clearly benefit from a joint replacement but were apprehensive about doing so. When I ask why, they say someone told them the new knee will only last 10 years. I’m not sure if that meme ever had any basis in reality; I’ve rehabilitated a lot of total knees and I really don’t see very many revisions, and it’s even less likely true now with newer and better quality knee components.

I tell my patients that if their knee arthritis is really holding them back from physical activity they should probably get it replaced. If you wait too long inactivity will make the rest of the body fall apart, which could include things as bad as heart attacks and strokes. So while I don’t think anyone should rush into the procedure, I think a lot of people put it off for too long. Besides enduring the pain and health problems from inactivity, weight gain from inactivity makes you a higher risk for surgery with much larger risk of serious complications. In fact a number of my cardiovascular patients, when being seen for overall function, gait training and balance, often have REALLY bad knees and/or hip arthritis that they probably should have had replaced 20 years ago, but now they are poor surgical candidates and no doctor will perform the surgery.

Thanks for reading my blog. If you have any questions or comments (even hostile ones) please don’t hesitate to ask/share. If you’re reading one of my older blogs, perhaps unrelated to neck or back pain, and it helps you, please remember Spinal Flow Yoga for you or someone you know in the future.

Chad Reilly is a Physical Therapist, obtaining his Master’s in Physical Therapy from Northern Arizona University. He graduated Summa Cum Laude with a B.S. Exercise Science also from NAU. He is a Certified Strength and Conditioning Specialist, and holds a USA Weightlifting Club Coach Certification as well as a NASM Personal Training Certificate. Chad completed his Yoga Teacher Training at Sampoorna Yoga in Goa, India.

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