Study: One Third of Knee Replacement Surgeries ‘Inappropriate’

Study: One Third of Knee Replacement Surgeries ‘Inappropriate’

Over a third of the total knee replacements in the U.S. are inappropriate, according to researchers who found that many patients had pain and other symptoms that were too mild to justify having the surgery. Over 600,000 knee replacements are performed annually in the U.S.

During the surgery, doctors replace a diseased or damaged joint with metal or plastic components that allow for continued motion of the knee. Postoperative pain can be severe and recovery periods last 6 weeks or longer, often with extensive physical therapy.

Operendo2017Osteoarthritis, a degenerative joint disease that causes pain and swelling in the knee, is the leading reason why people have the surgery. But some experts believe the procedure is over-utilized and too often recommended by doctors.

In the past 15 years, the number of total knee replacements (TKR) has grown significantly, with studies showing an annual increase of nearly 100% in surgeries between 1991 and 2010. The number of Medicare-covered TKR surgeries grew by 162% annually over the same period.

“To my knowledge, ours is the first U.S. study to compare validated appropriateness criteria with actual cases of knee replacement surgery,” said lead author Dr. Daniel Riddle from the Department of Physical Therapy at Virginia Commonwealth University.

Riddle and his colleagues evaluated 175 knee replacement patients who were enrolled in the Osteoarthritis Initiative — a 5-year study funded by the National Institutes of Health. They used an evaluation system developed by Escobar et al. along with the Western Ontario and McMaster Universities Arthritis Index (WOMAC) Pain and Physical Function scales.

They found that only 44% of the knee replacement surgeries could be classified as appropriate, with 22% rated inconclusive and 34% deemed inappropriate.

A rating of ‘‘inconclusive’’ indicates that the expected benefits and harms to the patient are roughly equal. An “inappropriate’’ rating indicates the expected harms outweigh the expected benefits.

“Our finding that one third of knee replacements were inappropriate was higher than expected and linked to variation in knee pain OA severity and functional loss. These data highlight the need to develop patient selection criteria in the U.S.,” said Riddle.

PTG_PThe study is being published in Arthritis & Rheumatology, a journal of the American College of Rheumatology.

“The implication that fewer than half of TKRs performed in the U.S. are appropriate and that fully one third are inappropriate raises serious concern about overutilization,” wrote Dr. Jeffery Katz in an editorial also published in Arthritis & Rheumatology.

Katz, a professor at the Orthopedic and Arthritis Center for Outcomes Research at Brigham and Women’s Hospital in Boston, said he was concerned that doctors were offering TKR surgeries to patients who had mild pain and little loss of function in their knees.

“We cannot be sure that TKR will improve such patients at all. I have similar, substantial reservations about performing TKR subjects with no joint space narrowing at all,” he wrote.

“As a community of providers, we implore our patients and the public at large to engage in exercise and physical activity in order to delay functional decline and to preserve and augment functional status. We must consider whether it is advisable and affordable to use costly technology such as TKR in the same fashion.”

Costs can vary depending on the surgeon and insurance coverage, but the average hospital charge for TKR surgery in the U.S. is about $50,000.

A recent study in Germany found that arthroscopic knee surgery provides no benefit to patients with osteoarthritis, and does not relieve pain any better than physical therapy or over-the-counter pain medications.

Arthroscopy of the knee is a procedure in which a surgeon inserts a thin tube with a camera through a small incision in the skin to view the inside of the knee. The surgeon removes damaged cartilage and loose bone by flushing the knee joint with saline solution.

Osteoarthritis is the most common form of arthritis, and affects more than 27 million Americans and over 100 million people worldwide. Osteoarthritis of the knee is more prevalent and severe in women, elderly and the obese.

Authored by: Pat Anson, Editor

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Matt Whitehead

Two important things to look at when thinking about knee (or any other joint) replacement is: What caused my knee to develop osteoarthritis and degenerate? And: How can I make sure that this new joint will last as long as possible and work as well as possible? These two articles can help answer these two very important questions:

Gerald Bruno

Perhaps your higher satisfaction rate is a result of your rigorous screening for acceptable candidates. I would whole-heartedly agree that TKR is a good option for anyone who has tried everything else and is still sitting on the couch in severe pain, popping narcotic pills.

Great review of a very challenging topic - I would love to know what the criteria was for ‘appropriate’ in this study. Most multi-center studies of 1000’s of patients show that about 90% are happy they did it and feel better. Sure, there are outliers, but most people are happy after surgery. I have only performed this operation on people who have tried it all - supplements, ibuprofen, icing, weight loss, activity modification - they have to come to me asking for it and convince me everything else has been tried. These people are happy after surgery. The alternative for many is to sit on the couch and do very little because of unbearable pain. Surgery gets people off the narcotics for good. Certainly surgery is only for a select few who fail other options, but I promise you number the people who are satisfied is larger than you may think. All the best !


At age 41, I had a TRK. A motorcycle vs SUV accident led to a traumatic loss of all my joint cartilage. Within 5 years, I went on to develop Sacro-iliac Joint Pain/Dysfunction on the same side. I had failed iFuse and having trouble locating a doctor to repair the problem. I am sure there is a relationship between issues.

Gerald Bruno

I was faced with this decision about 10 years ago and decided to try a mixture of natural joint supplements to at least delay the inevitable. I was told I had no cartilage in my right knee and would have to live with the pain until I had the surgery. I’m a pharmacist, with a recently kindled interest in natural products, and decided to try different joint health supplements as an alternative to surgery. I tried glucosamine and chondroiten and they didn’t help. I lived with chronic pain for several years before I came upon the use of fish oil and rosehips to reduce OA pain and stiffness. This combination worked very well and surprised me with the unexpected effect. I studied other ingredients and found that my pain could be totally eliminated when I added krill oil, collagen II and pine bark extract. Long story short, I’ve been using this combination (now sold in a single capsule as Omniflex) for about 7 years and have complete use of my knee joint for vigorous exercise. I kinow this combination won’t work as well as it did for me for everyone, but the results have been remarkable for me and other OA sufferers who have tried it. The healthcare system has found a new cash cow in TKR and are aggressively promoting TKR as simple and only minimally painful procedure that will give you back your active life. I’m sure this is true in some cases, but the great majority suffer serious risks, continue to have pain and stiffness after the surgery, and are limited in physical activity to avoid shortening the time-interval to the next replacement.


Now the overutilization of inappropriate knee surgeries to try and cut down on prescribing pain meds. I guess because the drs can tell themselves they did their job and fixed it, that makes them feel better. It doesn’t matter if the patient is in more pain than before.