Knee Replacement Would Be More Cost Effective If Limited To Those With Severe Symptoms Interview with:

Bart S Ferket, MD, PhD Assistant Professor, Population Health Science and Policy Icahn School of Medicine at Mount Sinai

Dr. Bart Ferket

Bart S Ferket, MD, PhD
Assistant Professor, Population Health Science and Policy
Icahn School of Medicine at Mount Sinai What is the background for this study?

Response: The annual rate of total knee replacement in the US has doubled since 2000, and especially in those aged 45-65 utilization of this procedure has increased. The increase in practice cannot fully be explained by an increase in the prevalence of osteoarthritis and population growth, and has been partly attributed to expansion to people with less severe symptoms. The total number of procedures performed each year now exceeds 640,000. The evidence for the benefit of total knee replacement has been based on studies without a comparison group of no total knee replacement, and so far only one randomized clinical trial has been published. Although the published literature shows large improvements of pain, physical functioning and overall quality of life following the procedure, patients included in these studies generally had severe preoperative symptoms. A number of studies have suggested, however, that up to a third of recipients of total knee replacement show no benefit, and that those with poor physical functioning before surgery may show larger improvements. Therefore, the current US patient population undergoing total knee replacement might show less significant improvement in symptoms on average as compared with a hypothetical scenario in which eligibility is limited to those with more severe symptoms. What are the main findings?

Response: Our study findings confirm that quality of life outcomes generally improve after total knee replacement, in terms of fewer knee osteoarthritis symptoms such as pain, stiffness, limitation in functioning of the knee, and also better general physical well-being. However, these improvements were found to be larger when patients with higher physical symptom levels before surgery were operated on. In addition, we demonstrated that the practice of total knee replacement as currently performed in the U.S. may be economically unattractive. It would become more cost effective if the procedure were restricted to patients with more severe knee symptoms. What should readers take away from your report?

Response: It may seem not surprising that those with more severe physical problems due to knee osteoarthritis would benefit mostly from total knee replacement surgery. On the other hand, since patients should have experienced considerable symptoms that lead to the decision for surgery, there must be room for much improvement in most patients one might think. Others have however demonstrated that surgery is often performed also in patients with limited symptom levels, when quality of life has been only moderately affected. Yet, as far as we know, no study has investigated whether the effect of surgery varies according to preoperative symptom levels, while making comparisons with similar patients who did not receive surgery or received surgery later on. Our findings demonstrate that not all patients with knee osteoarthritis are expected to benefit from total knee replacement to the same extent.

There will be patients who will benefit more than other patients, and this likely depends on the severity of the physical symptoms that patients experience from osteoarthritis prior to the procedure. When comparing costs and health benefits following medical interventions, we generally rather choose interventions that lead to more health benefits and are cheaper than interventions that have smaller or similar health benefits and are more expensive. When comparing different practices of knee replacement, we learned that performing surgery in those with more severe physical symptoms would not lead to a significant loss of health benefits in the total knee osteoarthritis population as compared to performing surgery as seen in current U.S. practice. Because we, in addition, found that it is on average cheaper to limit surgery to those with more severe symptom levels, a more restrictive total knee replacement practice seems preferable from an economic perspective. What recommendations do you have for future research as a result of this study?

Response: Almost all osteoarthritis experts agree on the fact that patients should be offered conservative treatment options in an optimal way before surgery is considered, but in reality we still see in many cases that conservative treatment has not been offered optimally before surgery is done (see for example Future research should therefore focus on better healthcare delivery of conservative treatment programs. The basic conservative treatment strategy includes exercise programs, weight loss programs for overweight individuals with knee osteoarthritis, patient education and safe first-line pain medication (e.g. Acetaminophen and/or topical NSAIDs). Other conservative treatment options that can be considered are more advanced pain therapy (e.g. supportive shock-absorbing footwear, local hot and cold compresses, transcutaneous electrical nerve stimulation), intra-articular corticosteroid injections, and biomechanical interventions (adjunctive braces, adjunctive assistive devices for activities or daily living). A good example of such a healthcare delivery program is the Good Life with osteoArthritis in Denmark (GLA:D) initiative see In addition, it seems best to discuss with the patient what the chance is of having improvement of symptoms with surgery in the context of the potential harms. Ideally, also costs to the healthcare system and society should be considered by physicians in the decision making (see for example More research should be done on developing and validating tools that can be used to guide these discussions and decision-making. Is there anything else you would like to add?

Response: Our study was not designed to answer questions for specific patients, and thus only gives estimates of outcomes at the group level. We demonstrated that on average it would be better to perform surgery in patients with more severe physical symptoms, but the qualification “better” is made from a perspective of the U.S. healthcare system. From a patient’s perspective it may be that also in less severe symptoms, surgery would be the best option. This depends on how the patient would value improvement of his/her symptoms and the potential harms that are associated with surgery (risk of complications, and risk of revision surgery).

Funding: The Osteoarthritis Initiative (OAI) is a public-private partnership comprised of five contracts (N01-AR-2-2258; N01-AR-2-2259; N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the National Institutes of Health, a branch of the Department of Health and Human Services, and conducted by the OAI Study Investigators. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corporation, GlaxoSmithKline, and Pfizer. Private sector funding for the OAI is managed by the Foundation for the National Institutes of Health. This manuscript was prepared with an OAI public use dataset and does not necessarily reflect the opinions or views of the OAI investigators, the NIH, or the private funding partners. Multicenter Osteoarthritis Study (MOST) receives four cooperative grants (Felson, AG18820; Torner, AG18832; Lewis, AG18947; and Nevitt, AG19069) funded by the National Institutes of Health, a branch of the Department of Health and Human Services, and conducted by MOST study investigators. This manuscript was prepared with MOST data and does not necessarily reflect the opinions or views of MOST investigators. BF is supported in part by American Heart Association grant No 16MCPRP31030016.

Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: no financial relationships with any organizations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work. Thank you for your contribution to the community.


Impact of total knee replacement practice: cost effectiveness analysis of data from the Osteoarthritis Initiative
BMJ 2017; 356 doi: (Published 28 March 2017)Cite this as: BMJ 2017;356:j1131


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Last Updated on March 29, 2017 by Marie Benz MD FAAD