It’s common for orthopaedic surgeons and sports medicine specialists to recommend the injection of artificial “lubricant” into knees and other arthritic joints, or for a “pseudo-arthritis” like patellofemoral syndrome (PFPS).1 The actual substances are “hyaluronan” and “hylan” (Durolane®) which are basically synthetic replacements for the slippery component of the fluid in your joints. It’s fairly clear that the procedure is common simply because the idea of adding some lube to your knees really sounds like a good idea — so good that it’s done in spite of the fact that it barely works!
I’m no surgeon or scientist myself, and I don’t even play one on TV … but I can certainly quote them. The authors of a 2003 summary of this subject for the Journal of the American Medical Association2 said that injecting synovial fluid into your knee …
… has a small effect when compared with … placebo. The presence of publication bias suggests even this effect may be overestimated.
That 2003 assessment is supported by a bigger 2012 one.3 Nearly 90 trials were reviewed and determined that this treatment is associated “with a small and clinically irrelevant benefit and an increased risk for serious adverse events.” And another 2015 review piled on: “did not show clinically important differences.”4
Take-home message? Combining injections and wishful thinking is bad news.
No honest person could possibly look at the available scientific evidence and fail to come to the conclusion that the value of injecting artificial joint fluids into your knees is, in a word, underwhelming. At best. I’m inclined to say that these injections are simply all washed up scientifically. Case closed.
Risks of hyaluronan injection
Many patients are justifiably cautious about accepting the prescription of invasive procedures, even “just” an injection. Even when the risks are relatively low — which they are here — things can still go wrong any time you stick a needle into a knee. There is still a considerable personal and social “overhead” to such procedures. We should generally avoid any kind of invasive medical procedure unless the benefits are really quite clear. Really, like a charge of murder, it should probably be proven “beyond a reasonable doubt.” Such proof is simply not present in this case. And I have heard reports of nasty reactions. They are clearly uncommon, but they do occur. No injection is ever completely risk-free.
Important perspective: you can treat osteoarthritis with a placebo surgery
Bear in mind when you consider this treatment method that in 2002 a (now famous) study showed a truly spectacular placebo effect.5
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).
The point is that the conditions inside your knee are probably not nearly as important as you might think.
What about other joints?
Maybe this stuff works for shoulder pain? A 2008 study in Journal of Bone & Joint Surgery (American) found that injections of sodium hyaluronate into stubbornly painful shoulders were pretty helpful. It is, of course, completely possible that shoulders respond differently to this treatment than knees. It’s also possible there was something wrong with the study. But it’s worth noting.
Perhaps for the jaw? It’s also worth noting that a review found “insufficient evidence to either support or refute the use of hyaluronate for treating patients with temporomandibular joint disorders.”6
Injections like this are catnip for cranks because they sound modern and plausible, and deliver terrific placebo, but their legitimacy is completely opaque to consumers. Even if viscosupplementation was legit, the consumer would still be faced with the impossibility of knowing. Consider this example from Consumer Health Digest #20-14, and note the scale of the operation (many clinics):
Knee-injecting chiropractor settles False Claim Act allegations
David Podell, a chiropractor who previously owned and managed a clinic in Edgewater, New Jersey, has agreed to pay the United States $2 million to resolve False Claims Act allegations that he knowingly billed Medicare for medically unnecessary viscosupplementation injections and knee braces and received illegal kickbacks.7 Podell and a business partner also promoted a business model to other chiropractors for running and marketing a clinic that specialized in the treatment of osteoarthritis through the administration of fluoroscopic-guided viscosupplementation injections and the provision of knee braces. This led to the formation of Osteo Relief Institutes (ORIs), from which—through his business partner—Podell received a percentage of their collections. The settlement follows the government's earlier settlement with seven former ORIs and their owners, who agreed to pay the United States a total of more than $7.1 million to resolve their False Claims Act liability. … Podell allegedly caused his clinic and other ORIs to:
- bill Medicare for viscosupplementation injections for patients who did not need them
- use multiple brands of viscosupplements successively on patients without clinical support
- use discounted viscosupplements reimported from foreign countries
- provide unnecessary custom knee braces to patients
- solicit and receive kickbacks from a manufacturer of knee braces in exchange for ordering more of the manufacturer's braces for his clinic
Related surgeries are also useless
The effectiveness of many orthopedic surgeries has been under seige since the early 2000s. It’s clear that many of them do not work,8 and popular knee surgeries in particular are scandalously ineffective. In addition to the failures of injecting lubricant, two other extremely common knee surgeries have also been condemned by one scientific test after another:
- partial meniscectomy — trimming and “cleaning up” torn and frayed menisci, the pads of cartilage in the knee join9
- knee debridement — “polishing” rough arthritic joint surfaces10
Medical guidelines now recommend against these procedures even when the need seems “obvious.”11
In addition to their futility, of course all surgeries involve risk: Thorlund et al reported 4 harmful outcomes per thousand surgeries, including symptomatic deep venous thrombosis, pulmonary embolism, infection, and death.
About Paul Ingraham
I am a science writer in Vancouver, Canada. I was a Registered Massage Therapist for a decade and the assistant editor of ScienceBasedMedicine.org for several years. I’ve had many injuries as a runner and ultimate player, and I’ve been a chronic pain patient myself since 2015. Full bio. See you on Facebook or Twitter.
This article is a free chapter from PainScience.com’s huge patellofemoral pain syndrome (PFPS) tutorial, one of 100 chapters in all. The full book contains more thorough analysis of knee “lube jobs,” plus practical advice, tips, and tricks for managing patellofemoral pain. There are also several other excerpts and articles on the site about patellofemoral pain and related topics:
- Massage Therapy for Your Quads — Perfect Spot No. 8, another one for runners, the distal vastus lateralis of the quadriceps group
- IT Band & Patellofemoral Pain Defy Common Sense — The science shows that you can’t blame runner’s knee on structural quirks that seem like “obvious” problems
- Do Women Get More Knee Pain? — The relationship between gender and knee pain, especially runner’s knee (IT band syndrome, patellofemoral pain)
- What Can a Runner With Knee Pain Do at the Gym? — Some training options and considerations for runners (and others) with overuse injuries of the knee
- Patellofemoral Pain Diagnosis with Bone Scan — If you have anterior knee pain, should you bother x-ray, MRI, CT scan, or bone scan?
- Does Cartilage Regeneration Work? — A review of knee cartilage “patching” with autologous chondrocyte implantation (ACI)
- Diagnosing Runner’s Knee — It usually starts with lateral knee pain during and after runs, but there are two major types
- Does Hip Strengthening Work for IT Band Syndrome? — The popular “weak hips” theory is itself weak
- Patellofemoral Pain & the Vastus Medialis Myth — Can just one quarter of the quadriceps be the key to anterior knee pain?
- Patellofemoral Tracking Syndrome — The beating heart of the conventional wisdom about patellofemoral pain is mostly nonsense
- Knee Surgery Sure is Useless! — Evidence that arthroscopic knee surgery for osteoarthritis is about as useful as a Nerf hammer
- Is Running on Pavement Risky? — Hard-surface running may a be risk factor for running injuries like patellofemoral pain, IT band syndrome, shin splints, and plantar fasciitis
What’s new in this article?
Apr 14, 2020 — Added example of fraudulent promotion of unnecessary viscosupplementation.
2018 — Added citation to the most recent review available, Jevsevar 2015.
2016 — Added a section about other surgical procedures for context.
2017 — Science update, cited Siemieniuk.
2008 — Publication.
- Patellofemoral pain syndrome is not osteoarthritis, although they do get confused, because of the way typical patellar pain feels — a nagging ache — and a loose correlation with a slight degeneration of the kneecap cartilage (chondromalacia patellae). But, because it is perceived as being arthritis-y, it is a popular target for artificial synovial fluid injection.
- Lo GH, LaValley M, McAlindon T, Felson DT. Intra-articular hyaluronic acid in treatment of knee osteoarthritis: a meta-analysis. JAMA. 2003;290(23):3115–3121.
- Rutjes AW, Jüni P, da Costa BR, et al. Viscosupplementation for Osteoarthritis of the Knee: A Systematic Review and Meta-analysis. Ann Intern Med. 2012 Aug;157(3):180–91. PubMed #22868835 ❐
- Jevsevar D, Donnelly P, Brown GA, Cummins DS. Viscosupplementation for Osteoarthritis of the Knee: A Systematic Review of the Evidence. J Bone Joint Surg Am. 2015 Dec;97(24):2047–60. PubMed #26677239 ❐
- 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 ❐
- Shi Z, Guo C, Awad M. Hyaluronate for temporomandibular joint disorders. Coch. 2002. PainSci #56202 ❐
- New Jersey chiropractor agrees to pay $2 million to resolve allegations of unnecessary knee injections and knee braces and related kickbacks. US Department of Justice news release. April 6, 2020.
- 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 ❐
This review of a half dozen good quality tests of four popular orthopedic (“carpentry”) surgeries found that none of them were more effective than a placebo. It’s an eyebrow-raiser that Louw et al could find only six good (controlled) trials of orthopedic surgeries, and all of them were bad news.
Surgeries have always been surprisingly based on tradition, authority, and educated guessing rather than good scientific trials; as they are tested properly, compared to a placebo (a sham surgery), many are failing the test. This review introduction is excellent, and does a great job of explaining the problem. As of 2016, this is the best academic citation to support the claim that “sham surgery has shown to be just as effective as actual surgery in reducing pain and disability.” The need for placebo-controlled trials of surgeries (and the damning results) is explored in much greater detail — and more readably — in the excellent book, Surgery: The ultimate placebo, by Ian Harris.
The surgeries that failed their tests were:
- vertebroplasty for osteoporotic compression fractures (stabilizing crushed verebtrae)
- intradiscal electrothermal therapy (burninating nerve fibres)
- arthroscopic debridement for osteoarthritis (“polishing” rough arthritic joint surfaces)
- open debridement of common extensor tendons for tennis elbow (scraping the tendon)
- www.nytimes.com [Internet]. Kolata G. The Right to Know That an Operation Is ‘Next to Useless’; 2016 August 3 [cited 18 Aug 28].
An excellent plain language overview of the scandalous futility of meniscectomy, from the relentless Gina Kolata at the NY Times. For a formal scientific review, see Thorlund.
- Ingraham. Knee Surgery Sure is Useless! Evidence that arthroscopic knee surgery for osteoarthritis is about as useful as a Nerf hammer. ❐ PainScience.com. 1234 words. For a scientific review, see
- 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 ❐
These guidelines “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.” The authors believe this is the last word on the subject: “further research is unlikely to alter this recommendation.”