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I don't knee surgery

placebo knee surgery.jpg

Let's say you suffer from osteoarthritis of the knee. What's a common diagnosis for full recovery?  Arthroscopic surgery, or a keyhole surgery in your knee.

Except, do you really kneed it?

Baylor College of Medicine in Houston Texas tried something very different:

  • They randomly distributed 180 patients with knee pain into 3 groups. 

  • All 3 groups underwent the first part of arthroscopic surgery - a few small incisions were made into the knee. But that's where the similarities end.

  • Group 1 followed the normal process of debridement - a small camera is inserted to assess the damage, and the worn out or loose cartillage is cut away

  • Group 2 followed the normal process of arthroscopic lavage - a small camera is inserted to assess the damage, and the bad cartilage is flushed out.

  • Group 3, our placebo group - well, nothing happened. The experimenters pretended to go through the surgery by getting the patient on the operating table, having all doctors geared out. But the doctors did no actual procedure, not even inserting the small camera. They merely waited, and then closed up the incisions. 

  • For consistency, all 3 groups were operated (real or placebo) on by Dr. Bruce Moseley, a clinical associate professor of orthopaedics at Baylor.


Over the next 2 years, the patients in all 3 groups were monitored. They were not informed if they received real or placebo surgery. All patients reported moderate improvements in pain and ability to function.

|||   But neither of the first 2 groups which received actual treatment reported less pain or better function than the placebo group! 

Since then, the effectiveness of placebo surgeries have been repeatedly demonstrated. The findings for placebo knee surgery were later corroborated by various sources, like the Cochrane Collaboration review and the New England Journal of Medicine


Beyond knees, placebo surgeries have repatedly demonstrated effectiveness. Andy Carr and colleagues from the University of Oxford reviewed 53 trials of less invasive surgical interventions and found that, for half of surgeries tested, there was little sign that they were any better than placebo. Further, the placebo trial is now standard procedure for medication worldwide. Despite all the resources dedicated to pharmaceuticals, 90% of medication develop do no better than a placebo pill, even if the subject knows it is  a placebo. 

But why does this happen? What exactly is this wizardry, where thinking there is treatment is as good or even better than treatment itself? 

We explore this further in the chapter: why do placebos work?

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