Key messages
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People with mild to severe knee osteoarthritis who have total knee replacement surgery followed by a non-surgical treatment programme may feel a small reduction in pain at a level that offers a real benefit; may have a small improvement in physical function that may not offer a real benefit; and may have a small reduction in the need for a follow-up knee surgery compared to a non-surgical treatment programme alone. There is likely no difference in terms of real benefits between treatment groups in health-related quality of life.
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The effect of total knee replacement surgery followed by a non-surgical treatment programme on the risk of serious unwanted effects and withdrawals due to unwanted effects compared to a non-surgical treatment programme alone is very uncertain.
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Future studies are needed to compare total knee replacement surgery with non-surgical treatments for osteoarthritis. These studies should look at the benefits and risks of treatment and patient satisfaction.
What is knee osteoarthritis?
Knee osteoarthritis is a common and progressing condition that affects the knee joint and area around it. Osteoarthritis causes pain, stiffness, and reduced mobility, which can be mild, moderate, or severe. These symptoms affect the quality of life of millions of people worldwide.
How is knee osteoarthritis treated?
Treatment for moderate to severe knee osteoarthritis includes non-surgical treatments and knee replacement surgery. The usual non-surgical treatment options are education, exercises, physiotherapy, weight loss, medications, and joint injections.
As osteoarthritis progresses, some people may need knee replacement surgery. During knee replacement surgery, the surgeon replaces the surfaces of the knee joint (shinbone, thighbone, and sometimes the kneecap) with artificial parts made of metal, plastic, or ceramic. A plastic spacer is also placed between the shinbone and thighbone to help the joint move smoothly.
There are many treatment options for knee osteoarthritis, and there is no one best option for everyone. To understand the treatment options, people with knee osteoarthritis need clear, trustworthy information about the possible benefits and risks of non-surgical treatment options and knee replacement surgery to be able to choose the treatment that best fits their personal values, goals, and lifestyle.
What did we want to find out?
We wanted to find out which treatment (knee replacement surgery, non-surgical treatments, dummy treatment, or fake treatment) works best for adults with moderate to severe knee osteoarthritis.
We also wanted to find out if adults who had knee replacement surgery, non-surgical treatments, dummy treatment, or fake treatment had any unwanted effects.
What did we do?
We searched for published studies in the last 15 years that looked at knee replacement surgery compared to non-surgical, dummy, or fake treatments in people with moderate to severe knee osteoarthritis. We summarised and compared the results of the studies and rated our confidence in the evidence based on factors such as study methods and sizes.
What did we find?
We found only one study that involved 100 adults with mild to severe osteoarthritis. The study tested total knee replacement surgery followed by a 12-week non-surgical programme compared to the same 12-week non-surgical programme alone. In the group that had total knee replacement surgery followed by a non-surgical programme, 32 out of 50 adults were women (64%), and people were on average 66 years old. In the group that received a non-surgical programme alone, 30 out of 50 adults were women (60%), and people were on average 66 years old.
Main results
Total knee replacement followed by a 12-week non-surgical programme compared to the same 12-week non-surgical programme alone:
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may reduce pain at one year at a level that offers a real benefit;
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may improve physical function at one year, but the improvement might not amount to a real benefit;
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may reduce the need for a follow-up knee surgery (revision or subsequent knee surgery and initial knee surgery);
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probably results in no difference in terms of real benefits between treatment groups in health-related quality of life at one year.
There was no evidence on patient satisfaction with treatment outcomes.
We are very uncertain about the effect of total knee replacement followed by a 12-week non-surgical programme compared to the same 12-week non-surgical programme alone on the risk of serious unwanted effects at one year and withdrawals due to unwanted effects.
What are the limitations of the evidence?
Our confidence in the evidence is only moderate to very low because we found only one small study conducted between 2011 and 2013; it was unclear how doctors decided who could have knee replacement surgery; a small number of people in the study had mild osteoarthritis instead of moderate to severe; and people who had severe pain the week before were not included in the study, which could have influenced the results of the review. Additionally, people in the study were aware of the treatment received, which could have affected the results.
How up-to-date is the evidence?
The evidence is current to January 2025.
Read the full abstract
Objectives
To assess the benefits and harms of TKA and PKA for people with moderate to severe knee osteoarthritis compared to placebo, sham (efficacy), or non-surgical interventions for the knee (effectiveness).
Search strategy
We searched CENTRAL, MEDLINE, Embase, and two trial registers from 2010 to January 2025. We also performed reference and citation checks. Two reviewers independently screened studies, extracted data, and assessed risk of bias and the certainty of evidence.
Authors' conclusions
Compared to a non-surgical programme alone, TKA followed by a non-surgical programme may reduce pain at a level that is clinically important; may improve physical function at a level that is not clinically important; and may reduce the need for follow-up knee surgery.
There is probably no clinically important difference in health-related quality of life between TKA followed by a non-surgical programme and a non-surgical programme alone.
TKA followed by a non-surgical programme may increase the risk of serious adverse events, but the evidence is very uncertain.
There may be no difference between groups in withdrawals due to adverse events, but the evidence is very uncertain.
The conclusions of this study should be interpreted with caution due to several limitations: the evidence is based on a single study conducted in Denmark; TKA eligibility criteria used by surgeons were not clearly reported; 12% of adults had mild osteoarthritis; adults who reported severe pain in the previous week were excluded; and the included study employed a broad definition of serious adverse events. These factors may affect the reliability and generalisability of the findings.
Funding
LPB was supported by the Arthritis Society PhD Award (#21‐0000000085), matched funding from the University of Ottawa and co‐supervisors' research funds, the Ontario Graduate Scholarship, and the University of Ottawa Admission Scholarship. In the past five years, LPB also received support from the Hans K. Uhthoff MD FRCSC Graduate Fellowship (#712240301930), the Queen Elizabeth II Graduate Scholarships in Science and Technology, the University of Ottawa Excellence Scholarship, the Eastern District of the Ontario Physiotherapy Association (#712140302327, #712200305332), and l’Ordre Professionnel de la Physiothérapie du Québec.
Registration
Protocol (2023) 10.1002/14651858.CD015378
