It’s a pleasure to report, for once, scientific news that is crystal clear and unambiguous: surgery for osteoarthritis of the knee joint [WebMD] is really, really pointless. We’re talking about “debridement” [Wikipedia] — basically filing down rough knee cartilage. It sounds like a good idea, in a way. I know I want my knee cartilage to be smooth. Unfortunately, it doesn’t work, and any surgeon still recommending this procedure is probably out of touch (although there’s always the chance of rare cases where it might still make sense).
For my readers, knowing about this is a valuable perspective on joint problems of all kinds — it really drives home one of the main themes of this website, which is that either:
- mechanical problems with joints aren’t as much of a problem as you probably thought, just as most “structural” theories of pain fall apart under examination
- and/or trying to fix them surgically is often useless and risky
A little knee surgery history
Way back in 2002, seventeen years ago now, Moseley et al published the results of a fascinating experiment that showed that people who received a fake arthroscopic knee surgery for osteoarthritis had results just as good as people who received the real surgery.1 It’s unusual, by the way, for surgeons to compare real surgeries to fake surgeries, and that in itself was interesting. But the humungous placebo effect was the really sensational thing.
Since then, other researchers have generally been finding more and more bad news about athroscopic surgery for knee pain, culiminating earlier this year with what was arguably a scientific death blow for the procedure: a large review concluded that “there is ‘gold’ level evidence that arthoscopic debridement has no benefit.”2 This is now part of a general trend of discovering that surgeries don’t actually work,3 especially orthopedic (“carpentry”) surgeries.4
More negative results … even from surgeons! Especially from surgeons.
In 2008, the New England Journal of Medicine has added more experimental evidence to the pile, reporting that “surgery for osteoarthritis of the knee provides no additional benefit to optimized physical and medical therapy.”5
And then in 2013 the American Academy of Orthopaedic Surgeons echoed that sentiment in a comprehensive report on treatments for knee arthritis.6 They praised radical treatments like exercise, weight loss, and regular painkillers, and denounced several particularly ineffective treatments: acupuncture, glucosamine, chondroitin, “lube jobs” (injection of joint lubricant)… and surgical lavage and debridement. Their very own cash cow.
That integrity is extremely noteworthy: an association of surgeons denouncing a profitable, common surgical treatment! Dr. Harriet Hall:
Critics who claim doctors are just out to make money, take note: if they were the evil money-grubbers some make them out to be, wouldn’t these surgeons want to promote income-generating arthroscopic lavage and debridement? Wouldn’t they want to suppress information about conservative treatments and keep patients in pain until they were desperate enough to consent to expensive joint replacement surgery? Gee, do you suppose maybe they really are just trying to do what’s best for their patients?
The debridement verdict is in
In science, replication of experimental results is the most important way that our confidence in a conclusion increases. The more surprising and counter-intuitive experimental results seem to be, the more important it is to do it again. And again. And again. Every time you get the same results, or similar results, from different scientists, using different methods, the more confident you can be that those results have something to do with “the truth.”
Well, we just keep getting the same results about this. It’s not controversial. This is something everyone can agree on.
So please do not debride your knees! In fact, be cautious and skeptical about all surgeries that allege to fix mechanical problems with joints — although some of them undoubtedly work, they are all on probation.
Oh, and one more thing: this is all the same for meniscectomy
This article has been about debridement so far. The situation is nearly identical to another common knee surgery: meniscectomy, or trimming and “cleaning up” torn and frayed menisci, the pads of cartilage in the knee joint.
There is a broad scientific consensus that meniscectomy is useless and risky for most patients.7 It produces results no better than a fake surgery,8 or exercise therapy.9 The risks of things going sideways are greater for those who need more repair, have been in pain longer, and have more arthritis going in.10
Meniscectomy has a strong common sense vibe to it. It clearly seems like a really good idea, especially in those cases with more vividly “mechanical” symptoms like snagging, locking, clunking, and buckling. Seems like cleaning that up a bit should be pure win, right? It is possible that meniscectomy is more effective for those patients, but even that is somewhat uncertain. A medium-sized study found that surgery versus a sham made no difference for “catching or occasional locking.”11 It might have worked out better for patients with worse symptoms, but we might be surprised by a test like that too.
The evidence is now overwhelming that meniscectomy just doesn’t do what educated, smart, well-intentioned surgeons have assumed for a long time now.
We really need to redefine what “obvious” means in medicine. Because 2017 guidelines (British Medical Journal) “make a strong recommendation against the use of arthroscopy in nearly all patients with degenerative knee disease … ” regardless of “imaging evidence of osteoarthritis, mechanical symptoms, or sudden symptom onset.”12 The authors believe this is the last word on the subject: “further research is unlikely to alter this recommendation.”
For a great plain language overview of the trouble with meniscectomy, see The Right to Know That an Operation Is ‘Next to Useless’.
About Paul Ingraham
I am a science writer, former massage therapist, and I was the assistant editor at ScienceBasedMedicine.org for several years. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook or Twitter.
More information about knee pain
Most of the knee pain information on this website is about patellofemoral syndrome and iliotibial band syndrome, the two most common runner’s knee conditions, typically causing pain on the front and side of the knee respectively (learn more about the difference). Arthritis is not my usual subject matter, although I do keep tabs on it (particularly because of the way it is routinely confused with arthritis).
- PS Does Cartilage Regeneration Work? — A review of knee cartilage “patching” with autologous chondrocyte implantation (ACI)
- PS Patellofemoral Pain Diagnosis with Bone Scan — If you have anterior knee pain, should you bother x-ray, MRI, CT scan, or bone scan?
- PS Patellofemoral Pain & the Vastus Medialis Myth — Can just one quarter of the quadriceps be the key to anterior knee pain?
- PS Patellofemoral Tracking Syndrome — The beating heart of the conventional wisdom about patellofemoral pain is mostly nonsense
- PS The Runners Knee Diagnostic Checklist — How to tell the difference between the two most common kinds of runner’s knee
- PS Massage Therapy for Your Quads — Perfect Spot No. 8, another one for runners, the distal vastus lateralis of the quadriceps group
- PS Should You Get A Lube Job for Your Arthritic Knee? — Reviewing the science of injecting artificial synovial fluid, especially for patellofemoral pain
- PS Do Women Get More Knee Pain? — The relationship between gender and knee pain, especially runner’s knee (IT band syndrome, patellofemoral pain)
- PS Does Hip Strengthening Work for IT Band Syndrome? — The popular “weak hips” theory is itself weak
- PS Iliotibial Band & Patellofemoral Pain Defy Biomechanical Expectations — The science shows that you can’t blame runner’s knee on structural quirks that seem like “obvious” problems
- PS Kinesio Taping Review — A quick analysis of that colourful therapy tape that was so popular at the Olympics. Does it help?
- PS Knee Replacement Surgery Doubts — Knee replacement is extremely popular, but still not yet based on good evidence of efficacy
What’s new in this article?
Five updates have been logged for this article since publication (2008). All PainScience.com updates are logged to show a long term commitment to quality, accuracy, and currency. more
Like good footnotes, update logging sets PainScience.com apart from most other health websites and blogs. It’s fine print, but important fine print, in the same spirit of transparency as the editing history available for Wikipedia pages.
I log any change to articles that might be of interest to a keen reader. Complete update logging started in 2016. Prior to that, I only logged major updates for the most popular and controversial articles.
See the What’s New? page for updates to all recent site updates.
2018 — Updated meniscectomy references and analysis.
2017 — Science update, cited Siemieniuk.
2016 — Added new section about the trouble with meniscectomy.
2016 — Added citations to Louw and Harris about ineffective surgeries in general.
2016 — Added more scientific context, related citations, and expert perspective.
2008 — Publication.
- Moseley JB, O’Malley K, Petersen NJ, et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med. 2002 Jul 11;347(2):81–8. PubMed #12110735. ❐ PainSci #56845. ❐
In this landmark and fascinating study, people with osteoarthritis improved equally well regardless of whether they received a real surgical procedure or a sham, which is a particularly striking example of the placebo effect and implies that belief can have an effect even on a “mechanical” knee problem. From the abstract: “In this controlled trial involving patients with osteoarthritis of the knee, the outcomes after arthroscopic lavage or arthroscopic debridement were no better than those after a placebo procedure.”
In 2008, these findings were fully supported by a Cochrane Collaboration review (Laupattarakasem) which concluded that “there is ‘gold’ level evidence that arthoscopic debridement has no benefit,” and by New England Journal of Medicine (Kirkley) which reported that “surgery for osteoarthritis of the knee provides no additional benefit to optimized physical and medical therapy.”
This study inspired more comparisons of orthopedic surgeries to shams. By 2016, at least four more popular surgeries have been shown to have no benefit (Louw 2016).BACK TO TEXT
- Laupattarakasem W, Laopaiboon M, Laupattarakasem P, Sumananont C. Arthroscopic debridement for knee osteoarthritis. Cochrane Database Syst Rev. 2008;(1):CD005118. BACK TO TEXT
- Harris I. Surgery: The ultimate placebo. NewSouth Publishing; 2016. BACK TO TEXT
- Louw A, Diener I, Fernández-de-Las-Peñas C, Puentedura EJ. Sham Surgery in Orthopedics: A Systematic Review of the Literature. Pain Med. 2016 Jul. PubMed #27402957. ❐ PainSci #53458. ❐ BACK TO TEXT
- Kirkley A, Birmingham TB, Litchfield RB, et al. A Randomized Trial of Arthroscopic Surgery for Osteoarthritis of the Knee. N Engl J Med. 2008;359(11):1097–1107. PainSci #56274. ❐ BACK TO TEXT
- American Academy of Orthopaedic Surgeons. Treatment of Osteoarthritis of the Knee – 2nd Edition. AAOS.org. 2013. PainSci #54555. ❐ BACK TO TEXT
- Thorlund JB, Juhl CB, Roos EM, Lohmander LS. Arthroscopic surgery for degenerative knee: systematic review and meta-analysis of benefits and harms. BMJ. 2015;350:h2747. PubMed #26080045. ❐ PainSci #53297. ❐ A review of nine studies as of 2015 presenting strong collective evidence that meniscectomy is a futile surgery for most patients. BACK TO TEXT
- Sihvonen R, Paavola M, Malmivaara A, et al. Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. N Engl J Med. 2013 Dec;369(26):2515–24. PubMed #24369076. ❐ “In this trial involving patients without knee osteoarthritis but with symptoms of a degenerative medial meniscus tear, the outcomes after arthroscopic partial meniscectomy were no better than those after a sham surgical procedure.” BACK TO TEXT
- Kise NJ, Risberg MA, Stensrud S, et al. Exercise therapy versus arthroscopic partial meniscectomy for degenerative meniscal tear in middle aged patients: randomised controlled trial with two year follow-up. BMJ. 2016;354:i3740. PubMed #27440192. ❐ PainSci #53299. ❐
This large trial compared exercise to surgical cleanup of the menisci and found “no clinically relevant difference was found between the two groups … at two years.” They didn’t include patients locked knees, trauma, and most had no osteoarthritis.BACK TO TEXT
- <<Eijgenraam BACK TO TEXT
- Sihvonen R, Englund M, Turkiewicz A, Järvinen TL; Finnish Degenerative Meniscal Lesion Study Group. Mechanical Symptoms and Arthroscopic Partial Meniscectomy in Patients With Degenerative Meniscus Tear: A Secondary Analysis of a Randomized Trial. Ann Intern Med. 2016 Apr;164(7):449–55. PubMed #26856620. ❐ BACK TO TEXT
- Siemieniuk RA, Harris IA, Agoritsas T, et al. Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline. BMJ. 2017 May;357:j1982. PubMed #28490431. ❐ PainSci #52778. ❐ BACK TO TEXT