Detailed guides to painful problems, treatments & more

The Complete Guide to Patellofemoral Pain Syndrome

An extremely detailed guide to rehab from patellofemoral pain syndrome (aka runner’s knee), with thorough reviews of every treatment option

Paul Ingraham • 475m read
Photo of many runners disappearing into the mist. A caption superimposed on the image reads: patellofemoral pain is a common and often chronic injury in runners (many non-runners too), causing pain mainly on the front of the knee.

Patellofemoral pain syndrome (PFPS), also known as runner’s knee, is the most common of all kinds of knee pain, causing pain around and under the kneecap. Almost anyone can get it, but it particularly affects runners, cyclists and hikers, and also office workers or anyone else who sits for a living. It’s also common in teens. Almost 40% of pro cyclists will get anterior knee pain in any given year,1 but runners are by far the most numerous victims, and PFPS is the most common of all runner’s knee injuries.2

Most people recover from PFPS with a little rest and then slowly working their way back to normal activity, but not everyone. This kind of runner’s knee can be extremely resistant to treatment, and sometimes becomes a seriously style-cramping chronic pain problem.

This deep-dive tutorial is for patients with serious and stubborn patellofemoral pain, and the professionals trying to help them. The main goal is to explore patellofemoral pain syndrome treatment and rehab, of course, but also diagnosis and the nature of the beast.

I survived a brain tumor. Knee rehab has been worse.

a reader

An overview of patellofemoral pain

Diagram contrasting the difference between the two kinds of runners’ knee, patellofemoral pain syndrome and IT band syndrome, showing how the former causes pain primarily on the front of the knee, while the latter causes pain primarily on the outside of the knee.

PFPS affects the kneecap & surrounding area. Don’t confuse it with iliotibial band syndrome (ITBS) which definitely affects primarily the outside of the knee (the lateral or outward-facing side of the knee). This picture is of a right knee.

Patellofemoral syndrome is a problem with pain that feels like it is mainly on the front of the knee, specifically on the underside of or somewhere around the edges of the kneecap. One or both knees can be affected. Patellofemoral pain is usually worse when climbing stairs or hills, or after sitting for a long time.

I’ll cover the basics in the form of answers to the most common questions. There will be much more detail about all of this later in the tutorial.

How painful is patellofemoral pain syndrome? PFPS can be painful enough to seriously interfere with walking, sitting, and sleeping. However, even severe cases are usually limited to about a 5 or 6 on a scale of 10. It’s not in same league as kidney stone pain.

Does patellofemoral syndrome cause swelling? Rarely and never severe. Swelling usually suggests a different diagnosis.

Does patellofemoral syndrome ever go away? Average cases usually back off within a few months with basic taking-it-easy therapy and maybe basic physical therapy.3 “Basic physical therapy” probably isn’t actually effective, but recovery proceeds anyway simply because the body is pretty good at healing.4

Unfortunately, some cases persist or get worse. It has already been going on for several months, the sky’s the limit: it won’t necessarily last forever, but it can.

How do you treat patellofemoral pain? Primarily with “load management,” especially more initial rest than most people realize they need — simple in theory, but challenging in practice, and it won’t work with all causes of anterior knee pain. Many doctors and therapists buy into the conventional wisdom that the problem is essentially “mechanical” and they try to fix it — with corrective exercise, stretching, and surgery, for instance — but this is a simplistic view of what’s wrong in the first place. Fortunately, a few medical experts suggest good alternatives, to be explained in detail below.

What happens if patellofemoral pain goes untreated? Since there is no proven or reliable treatment, there is also none to neglect. If untreated — which is effectively all most people do — patellofemoral pain may get better, stay the same, or get worse.

What exercises can I do with patellofemoral syndrome? It’s not so much “what” exercise you can do as “how soon” and “how hard” you can do them. You can do any exercise that doesn’t irritate the knee, at first, but nothing that does. As rehab progresses, you reintroduce more activities that load the knee, and eventually anything’s fair game.

Do you need surgery for patellofemoral syndrome? Rarely. It can become a realistic option for some severe chronic cases

Does patellofemoral pain affect teens more than adults? The incidence of patellofemoral pain in adolescents is only a little bit higher than it is in the general population, and it is generally less serious and stubborn. Patellofemoral pain in teens isn’t specifically covered in this tutorial. However, it’s still useful for young patients.5


Getting good care for patellofemoral pain is a challenge

Knee pain may be common, but it’s surprisingly hard to find good self-help information for it. Patellofemoral pain is one of the most misunderstood of all knee pain problems. There are countless shallow webpages about it, which all just repeat the same useless conventional wisdom.6 And not many doctors and therapists are prepared to treat tough cases. Sports medicine in general is amazingly primitive considering how much potential funding it has. You’d think anything affecting elite athletes with huge audiences would be getting more attention! The situation is improving, but only recently and it still has a long way to go.7

And so, many popular treatments for PFPS are of dubious value:

You should try to find good professional help, but that can be difficult — so it’s always a great idea to be as well informed as possible when you do it, or you can easily waste a lot of time and money on dubious therapies — even if this tutorial can’t give you “the answer,” I hope it can at least help you avoid wasting time and money on ineffective treatments.


What’s in a name? The many labels of patellofemoral pain

“Patellofemoral pain syndrome” is a surprisingly meaningless name. It basically means “strange kneecap pain,” but in Latin. “Anterior knee pain syndrome” is another common name with an even broader meaning, and it’s a little more direct and honest: it’s pain, and it’s on the front of your knee, ‘nuff said.

A humourous graphical definition of patellofemoral pain syndrome, showing the meaning of the root “patello” means “kneecap,” the word “pain” means “ow,” and “syndrome” means “kinda mysterious.”]

Sometimes the “pain” part is dropped and it is just called “patellofemoral syndrome” or PFS. Sometimes syndrome is swapped out for “disorder.” And sometimes pain is replaced with “stress,” emphasizing that it’s usually a repetitive strain injury: “patellofemoral stress syndrome.” Sometimes the femur is shunned, and people just talk about patellar pain — and indeed sometimes it probably is the kneecap itself, and not really the joint under it.

And the misspellings! No musculoskeletal condition is trickier. The number of poorly spelled Google searches for this condition is off the charts.13

“Patellofemoral pain syndrome” is the most common term. A syndrome is never a “diagnosis,” or not a good one anyway: it’s an unexplained distinctive pattern of symptoms. In the case of pain on the front of the knee, especially where overuse is a factor, we assume that those problems are coming from the patellofemoral joint, and the odds do favour that — but it’s hardly guaranteed. The patellofemoral joint is the prime suspect in most cases, but it’s not the only one. I will get into much more detail about other possibilities later in the guide.

Photo of a woman in a chair. Chair workers often suffer from patellofemoral pain syndrome.

Do you live in a chair?

“Chair warriors” who spend more than 4–6 hours per day suffer as much from knee pain as many runners. Woe to runners who also work all day in a chair.

“Runner’s knee” is a popular description among runners, of course, and they do get it more often than anyone else. But it is not a good term to use, because there are at least a half dozen other conditions that term could refer to, especially iliotibial band syndrome. And of course it excludes other people who get the condition — all those people with cyclist’s knees and hiker’s knees, for instance!

Calling it “runner’s knee” particularly leaves out people whose knees hurt while sitting and because of sitting. Office workers and other chair-bound workers really do suffer from PFPS in droves. In fact, another name for this condition is moviegoer’s knee because of the tendency of the condition to cause pain after sitting for a long time. This also explains the use of the term “theatre sign” among professionals, as in, “He’s got theatre sign — must be a case of movie-goer’s knee.” In my professional experience, however, you could just as well say, “He’s got desk job sign — must be a case of office worker’s knee.”

One more naming note: occasionally you’ll hear therapists or doctors call this condition “patellofemoral tracking syndrome” (PFTS) or even chondromalacia patellae (definitions and detail ahead), but these are blatantly in error: these are things that might be causes of the condition, but they are not the condition itself.


Part 2

Nature of the Beast

The (many) possible causes of patellofemoral syndrome

Officially, no one knows what causes it. Here is an entertaining selection of typical disclaimers from some scientific papers dating back to 1988:

That’s the official, reasonable position. Any honest doctor or therapist should be happy to admit that almost everything about PFPS is basically a mystery. But in practice, most doctors and therapists think and act like the conventional wisdom is adequate.

Short animation demonstrating the biomechanics of kneecaps, and why the patellofemoral joint is naturally overloaded and vulnerable.

The kneecap is all about leverage — we have kneecaps so that we can extend the knee more powerfully, as shown by this really nice little model (source unknown). But that leverage has a cost: the loading on the joint is perpetually more extreme, making the patellofemoral pain joint more vulnerable to fatigue & failure. More on this soon.

The conventional wisdom

I’m pleased to say that American Family Physician came around. They say that the mystery of PFPS has been solved. (That’s sarcasm.) In a tutorial for physicians published in 2007, they confidently declared the cause of PFPS:

[Patellofemoral pain syndrome] is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint.

Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75:194–202. PubMed 17263215 ❐ PainSci Bibliography 56699 ❐

Well, thank goodness! That’s nice and clear, isn’t it? The conventional wisdom says that patellofemoral pain syndrome is painful degeneration of the cartilage on the underside of the kneecap, caused by a “mechanical” failure of that joint. What kind of failure? A “tracking” problem, in which the patella doesn’t slide evenly in its groove or “track” on the femur. For this condition, we need yet another multisyllabic name: “patellofemoral tracking syndrome.”

Another syndrome? I’m afraid so. It even has almost the same acronym: PFTS instead of PFPS. The conventional wisdom is so entrenched that many professionals consider the “tracking” syndrome to be virtually synonymous with PFPS itself.

But the idea that tracking problems cause patellar pain has not been proven beyond a reasonable doubt. In fact, as I will show in the sections ahead, it’s incredibly difficult to even prove that these problems even coexist, let alone how much they have anything to do with each other … if anything at all. Even stranger, it turns out that tracking problems are extremely difficult to even identify, let alone blame for anything. And as if this wasn’t enough trouble for the conventional wisdom, it turns out that even the “degeneration” of the kneecap’s cartilage is a scientific myth … a myth that probably has little or nothing to do with patellofemoral pain syndrome!

Wow. That’s a lot of myths.

The evidence that tissue pathology does not explain chronic pain is overwhelming (e.g., in back pain, neck pain, and knee osteoarthritis).

Teaching people about pain — why do we keep beating around the bush?, by Lorimer Moseley, 2–3


Assault on the conventional wisdom about patellofemoral pain syndrome

Joints wear out, right? Comedian Louis CK:17

The doctor shows me an x-ray of my ankle and he’s like, “Yeah, your ankle’s just, uh … worn out.”

“What do you mean? I injured my ankle?”

He’s like, “No, it’s just shitty now.”

And yet! Pain in the patellofemoral joint mostly does not appear to be associated with any identifiable tissue degeneration or damage, dysfunction or malfunction, asymmetry or weakness.1819 Sometimes it just hurts, even though the knee — indeed, the whole leg — seem to be healthy in every way that we can measure knee health. And if that seems a bit odd, you ain’t seen nothing yet!

Even when the joint is degenerating…


Purchase full access to this tutorial for USD$1995. Continue reading this page immediately after purchase. See a complete table of contents below. Most content on is free.?

Almost everything on this website is free: about 80% of the site by wordcount, or 95% of the bigger pages. This page is only one of a few big ones that have a price tag. There are also hundreds of free articles, including several about patellar pain. Book sales — over 72,000 since 2007?This is a tough number for anyone to audit, because my customer database is completely private and highly secure. But if a regulatory agency ever said “show us your math,” I certainly could! This count is automatically updated once every day or two, and rounded down to the nearest 100. Due to some oddities in technology over the years, it’s probably a bit of an underestimate. — keep the lights on and allow me to publish everything else (without ads).

Q. Ack, what’s with that surprise price tag?!

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Paying in your own (non-USD) currency is always cheaper! My prices are set slightly lower than current exchange rates, but most cards charge extra for conversion.

Example: as a Canadian, if I pay $19.95 USD, my credit card converts it at a high rate and charges me $26.58 CAD. But if I select Canadian dollars here, I pay only $24.95 CAD.

Why so different? If you pay in United States dollars (USD), your credit card will convert the USD price to your card’s native currency, but the card companies often charge too much for conversion — it’s a way for them to make a little extra money, of course. So I offer my customers prices converted at slightly better than the current rate.

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I guarantee only education, not “results”

This book does not spell out a treatment “plan,” per se. There is no secret cure that will be revealed when you pay the fee. The entire reason the book exists is that there is not a good, reliable treatment for patellofemoral pain. It’s very important to state this clearly. Wouldn’t it be great if there were a proven treatment with minimal cost, inconvenience, or side effects? But medical science is nowhere close to this for most chronic pain conditions, and especially for patellofemoral pain.

However, there are good reasons for optimism.

What I can do is explain all the options, help you to confirm your diagnosis, and debunk bad ideas. It may or may not lead to a “cure,” but it will get you as close as you can get. Some readers will finally break free of their patellar pain. Others will make progress after ditching a counter-productive therapy, or trying an option they didn’t know about before. And maybe that is kind of miraculous.

Mostly what’s for sale here is simply a deep understanding of the subject and your options. For some people, it’s worth $20 just to feel like they aren’t overlooking something. In general, if it’s not in this tutorial, it probably doesn’t matter.

And $20 is lot cheaper than even a single appointment with most healthcare professionals. And you might just get more out of it.

Logos for Visa, Mastercard, and Amex.

Paying in your own (non-USD) currency is always cheaper! My prices are set slightly lower than current exchange rates, but most cards charge extra for conversion.

Example: as a Canadian, if I pay $19.95 USD, my credit card converts it at a high rate and charges me $26.58 CAD. But if I select Canadian dollars here, I pay only $24.95 CAD.

Why so different? If you pay in United States dollars (USD), your credit card will convert the USD price to your card’s native currency, but the card companies often charge too much for conversion — it’s a way for them to make a little extra money, of course. So I offer my customers prices converted at slightly better than the current rate.

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Answers to more of your frequently asked questions about patellofemoral pain

I covered some of the most common questions earlier in the introduction, and here are several more: the questions people are actually asking in large numbers (taken straight from Google searches). The answers are basic — they represent the truth, but not the whole truth. They are quick notes extracted from the more detailed answers in the full book.

Will a knee brace help patellofemoral syndrome? Bracing is no cure, but a soft and comfy brace may limit knee use while also making the knee feel a bit “safer,” which can provide some short term pain relief.

Is cycling good for patellofemoral syndrome? No and then yes. All forms of exercise that aggravate patellofemoral pain are bad for it in the early stages of rehab, and then slowly become good for it later on as your load tolerance increases.

Can I walk with patellofemoral pain syndrome? Yes, but less in the early stages of recovery, and it may make sense to avoid altogether for a while. Walking on stairs/hills should be treated as a much more significant source of knee stress than flat walking.

Can patellofemoral pain be cured? In rare cases, a specific cause can be identified and fixed to completely resolve the pain. But those cases are quite rare.

How do you sleep with patellofemoral syndrome? Avoid any joint position that seems to irritate it. Slight flexion is usually the safest and most comfortable position.

What is the best painkiller for knee pain? Topical anti-inflammatory drugs based on either salicylates or diclofenac.

Does patellofemoral syndrome lead to arthritis? Patellofemoral pain can probably contribute to the development of arthritis, but only a little, and only in the long-term.

How do you test for patellofemoral syndrome? You don’t. As a “syndrome,” patellofemoral pain is defined almost entirely by its symptoms; no objective sign is definitive.

How do you know if you have a torn meniscus in your knee? Damaged menisci are usually associated with excessive joint noise, erratic locking, instability, and giving way.

Can just the patella be replaced? It’s technically possible, but never actually done. The cartilage can be replaced, however.

Why does my knee hurt when I get up from sitting? Sitting is more stressful to the knee than most people realize. Simply bending the knee applies considerable pressure to the patellofemoral joint surfaces.

How do you fix a tilted kneecap? Odd patellar angles are common and not a cause of patellofemoral pain, and usually cannot be changed in any case. They are one of the “biomechanical bogeymen” of patellofemoral pain.

What is patellofemoral friction syndrome? It’s not a real name or concept, except as a common misunderstanding. It’s probably based on confusion with IT band friction syndrome (which is itself a misleading label, but one that referes to a well-known idea about how IT band syndrome allegedly works).

Logos for Visa, Mastercard, and Amex.

Paying in your own (non-USD) currency is always cheaper! My prices are set slightly lower than current exchange rates, but most cards charge extra for conversion.

Example: as a Canadian, if I pay $19.95 USD, my credit card converts it at a high rate and charges me $26.58 CAD. But if I select Canadian dollars here, I pay only $24.95 CAD.

Why so different? If you pay in United States dollars (USD), your credit card will convert the USD price to your card’s native currency, but the card companies often charge too much for conversion — it’s a way for them to make a little extra money, of course. So I offer my customers prices converted at slightly better than the current rate.

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Part 2.3


Reader feedback … good and bad

Testimonials on health care websites reek of quackery, so publishing them has always made me a bit queasy. But my testimonials are mostly about the quality of the information I’m selling, and I hope that makes all the difference. So here’s some highlights from the kind words I’ve received over the years … plus some of the common criticisms I receive, at the end. These are all genuine testimonials, mostly received by email. In many cases I withold or change names and identifying details.

I just finished your e-book about patellofemoral pain syndrome and wanted to say that it was very helpful! As a chronic sufferer of PFPS, I have personally experimented and learned the hard way about almost all of the experiences you mentioned and found most of them to be spot on. I wish I had found this information 15 years ago, but it was helpful to confirm that I'm not alone and reinforce what I learned through personal experience.

Jerry Taylor

Thanks for a well written, humorous and informative piece. Your book helped me understand what I did to my knee running and how to treat (and not treat!) stubborn injury. Might see you jogging through Stanley Park or water front, on one of our visits to daughter, love Vancouver.

Matt Randlett

I wanted to write a short thank you email for all the help you have brought me. Im a recently graduated medicine student from Argentina, and i have been getting knee pain for almost 8 months. I have been to the best traumatologists in the country, none who could explain correctly what was going on with my knee. They did exactly the kind of mistakes you constantly mention all along your book.By reading the tutorial i have at last fully understood what im up against, how to correctly fight it, and hopefully beat the crap out of this horrible pain.Just wanted to write this short thank you email, you should know your amazing work helps people all around the globe.

Petra Fellows

My name is Lexy, I’m a 23-year-old with patellofemoral syndrome. For the past six months. I don’t have any questions really, but I wanted to reach out and let you know how valuable your writing has been to me. I’m just an occasional visitor of, but when I get those mental waves of dread that tell me my injury is going to last forever, your writing style has been super helpful in putting things in perspective, and helping me be realistic, yet hopeful about my recovery. I’ve seen PTs, acupuncturists, orthopedic surgeons and doctors, many of which have given me shit advice and left me feeling upset and angry, or like my pain wasn’t being taken seriously. I thank you for creating a forum where I feel a sense of solidarity with other humans/athletes, and most importantly where I don’t feel like I have to pay a ridiculous amount of money to feel like a factory-line patient. I really appreciate that.

Shakil Irvine

I wanted to send you a quick email to deeply thank you for all your work. I grappled for 18-months with horrible knee pain that threw my life into a tailspin. Your books were critical for getting me on the path to healing. I have spent much of my career in health research and policy and really admire your ability to distill evidence and then present it clearly and accurately to a general audience. Thank you.

Franco Sargent

Your tutorial on patellarfemoral syndrome really cut through a lot of misinformation I’ve received from MDs and PTs.

Alastair Rosario

Given what I have learned about patellofemoral pain syndrome over the last two years through personal experience, your tutorial is probably the best summary of everything I have seen.


This has already served as a massive eye opener for me. It makes a huge amount of sense where previously there was only confusion.

Greg Bruce, “struggling masters athlete”

Just reading tutorial has already given me hope that I can finally get some relief from my chronic patellofemoral pain syndrome. Why didn’t I find this 2 years ago?! It has been so frustrating, both physically and emotionally, as I’m sure you already know from your patients. Your eBook is very enlightening and well written. Please feel free to use my comments as a testimonial. I was glad to see other testimonials, too — it’s nice to know that I’m not the only one who is struggling with this.

Melanie Caldwell, Yonkers, NY

Finding this information was a huge relief for me. I really did think I had “tried everything.” But I found pages and pages of stuff in your article that no other doctor or therapist had ever even mentioned.

Jared Foster, long-distance runner

One more noteworthy endorsement, with regards to this whole website and all of my books, submitted by a London physician specializing in chronic pain, medical education, and patient-advocacy (that’s a link to his excellent blog):

I’m writing to congratulate and thank you for your impressive ongoing review of musculoskeletal research. I teach a course, Medicine in Society, at St. Leonards Hospital in Hoxton. I originally stumbled across your website whilst looking for information about pain for my medical students, and have recommended your tutorials to them. Your work deserves special mention for its transparency, evidence base, clear presentation, educational content, regular documented updates, and lack of any commercial promotional material.

Dr. Jonathon Tomlinson, MBBS, DRCOG, MRCGP, MA, The Lawson Practice, London

What about criticism and complaints?

Oh, I get those too! I do not host public comments on for many reasons, but emailed constructive criticism, factual corrections, requests, and suggestions are all very welcome. I have made many important changes to this tutorial inspired directly by critical, informed reader feedback.

But you can’t make everyone happy! Some people demand their money back (and get it). I have about a 1% refund rate (far better than average in retail/e-commerce). The complaints of my most dissatisfied customers have strong themes:



Thanks to Dr. Scott Dye for helping me to understand and believe in my own unconventional ideas about patellofemoral pain syndrome, and by extension every other joint problem.

Extra special thanks to Tony Ingram, for substantial contributions of expertise and writing to this book in 2014 — the book is much better for it.

Thanks to every reader, client, and book customer for your curiosity, your faith, and your feedback and suggestions, and your stories most of all — without you, all of this would be impossible and pointless.

Writers go on and on about how grateful they are for the support they had while writing one measly book, but this website is actually a much bigger project than a book. was originally created in my so-called “spare time” with a lot of assistance from family and friends (see the origin story). Thanks to my wife for countless indulgences large and small; to my parents for (possibly blind) faith in me, and much copyediting; and to friends and technical mentors Mike, Dirk, Aaron, and Erin for endless useful chats, repeatedly saving my ass, plus actually building many of the nifty features of this website.

Special thanks to some professionals and experts who have been particularly inspiring and/or directly supportive: Dr. Rob Tarzwell, Dr. Steven Novella, Dr. David Gorski, Sam Homola, DC, Dr. Mark Crislip, Scott Gavura, Dr. Harriet Hall, Dr. Stephen Barrett, Dr. Greg Lehman, Dr. Jason Silvernail, Todd Hargrove, Nick Ng, Alice Sanvito, Dr. Chris Moyer, Lars Avemarie, PT, Dr. Brian James, Bodhi Haraldsson, Diane Jacobs, Adam Meakins, Sol Orwell, Laura Allen, James Fell, Dr. Ravensara Travillian, Dr. Neil O’Connell, Dr. Tony Ingram, Dr. Jim Eubanks, Kira Stoops, Dr. Bronnie Thompson, Dr. James Coyne, Alex Hutchinson, Dr. David Colquhoun, Bas Asselbergs … and almost certainly a dozen more I am embarrassed to have neglected.

I work “alone,” but not really, thanks to all these people.

I have some relationship with everyone named above, but there are also many experts who have influenced me that I am not privileged to know personally. Some of the most notable are: Drs. Lorimer Moseley, David Butler, Gordon Waddell, Robert Sapolsky, Brad Schoenfeld, Edzard Ernst, Jan Dommerholt, Simon Singh, Ben Goldacre, Atul Gawande, and Nikolai Boguduk.


About the 2nd Edition

The 2nd “edition” of the PFPS tutorial was launched on July 28, 2014, after months of collaboration with Tony Ingram, a Physical Therapist who did his Masters thesis on anterior knee pain. Tony was officially a co-author for a while, but retreated to focus on pursuing a PhD and a career in science.

Like all my books, this one was updated many times over the years, but changes were too small and spread out to constitute an “edition”: that had to wait for this, by far the largest ever major change to the book. It has several new sections, a lot of new science, and a strong (and overdue) new emphasis on the evidence-based value of exercise — reversing my grumpy anti-exercise position. It’s also much less exclusively about a single theory of knee pain than it was.

A new position on exercise

Exercise for patellofemoral pain syndrome is a good example of a treatment that works, but probably doesn’t work how most people think it works. I was anti-exercise before because the evidence just wasn’t there for it yet, and too many professionals fancied that they were prescribing exercise to change biomechanical parameters (e.g. patellar tracking) that correlated poorly with the condition. Such prescriptions tended to be overzealous: too much exercise, too soon for patients suffering from what is fundamentally an overuse condition.

Now there is good evidence that exercise is effective — hallelujah, some much-needed good news — but dosage and timing are key, and the biomechanical rationale still needs to be taken out with the trash.

Not just one guy’s theory any more

The previous version of the book had a significant weakness, a major idea about the nature of the beast (basically the whole “it’s the homeostasis, stupid,” ). The idea was plausible and elegant, but lacked adequate scientific support for an important basic point of the book. One advanced reader complained:

I didn’t buy your book so I could get one guy’s theory about how patellofemoral pain syndrome works.

Fair enough. She went on to say that it was probably a pretty good idea, just painfully unsupported. Simple as it is, that’s one of the best single constructive criticisms I’ve ever received. On the one hand, I unapologetically offer my take on these complex subjects. They are my books, and this is not a medical journal. On the other hand, I don’t want my take to be based solely on private speculation — if my opinion is to have much value, it should be clearly based on a diversity of expert and scientific sources. And so this is one of the major repairs in the 2nd edition. My basic point was sound, but badly needed some scientific and more diverse expert support — and now it has that.


Further Reading

A few more articles about patellofemoral pain syndrome and related topics:


What’s new in this tutorial?

The original publication date of this tutorial has been lost, but I think it was in 2004. It was quite rudimentary until 2007, when significant upgrades began. This change log was started in May 2007, along with many major improvements. As you can see, the tutorial has been updated many times since, and remains a live document.

Regular updates are a key feature of tutorials. As new science and information becomes available, I upgrade them, and the most recent version is always automatically available to customers. Unlike regular books, and even e-books (which can be obsolete by the time they are published, and can go years between editions) this document is updated at least once every three months and often much more. I also log updates, making it easy for readers to see what’s changed. This tutorial has gotten 130 major and minor updates since I started logging carefully in late 2009 (plus countless minor tweaks and touch-ups).

Jan 25, 2023 — Reorganization: Just a bit of housekeeping: rearranged the content and edited for clarity. [Updated section: 16 causes and diagnoses of anterior knee pain.]

2022 — Minor addition: Added a little information for cyclists about the effect of pedal crank length on knee loading. [Updated section: Make adjustments to bicycling … especially seat height.]

2022 — Major upgrade: Added more detail and several more uncommon diagnoses to consider. [Updated section: 16 causes and diagnoses of anterior knee pain.]

2022 — Added sub-topic: Added a discussion of ozone therapy, which just barely qualifies as a “regenerative” therapy, and my only advice is to avoid it, so it’s a minor addition here — but an interesting one. [Updated section: Regenerative medicine? PRP, ACI, stem cell therapy, ozone.]

2021 — New section: No notes. Just a new chapter. [Updated section: “Plantaris hypertonia” as a cause of runner’s knee.]

2021 — Proofreading: Top-to-bottom check for typos and other minor errors. They creep in over the years as I work on updates to the book. A good three dozen of the little buggers identified and fixed this time.

2021 — More and better: It’s not an important sub-topic for patellofemoral pain, but it certainly deserved more and better advice than I had previously offered. An obsolete point or two removed, and a more modern perspective added. [Updated section: Heat (briefly).]

2020 — New sub-topic: Added discussion of the (rather silly) idea that prolotherapy is a form of regenerative medicine. [Updated section: Prolotherapy is not relevant to patellofemoral pain syndrome.]

2020 — Major expansion: Added an introduction about regenerative medicine in general, a thorough discussion of autologous chondrocyte implantation, and some basic notes about stem cell therapy. [Updated section: Regenerative medicine? PRP, ACI, stem cell therapy, ozone.]

2020 — Upgraded: Substantial revision and modernization, with more attention given to skeptical concerns about icing. [Updated section: The power of power icing.]

2020 — Science update: Added more about the rationale for exercise therapy, citing Fu. [Updated section: And then came the exercise: The long term solution.]

2020 — Addition: Added osteochondritis dissecans to the list of other diagnoses to consider. [Updated section: 16 causes and diagnoses of anterior knee pain.]

2020 — Minor addition: Added sex to the list of activities that can involve potentially harmful knee stresses, depending on the position and, er, endurance. [Updated section: The art of rest: the challenge and the opportunity for patients who have supposedly “tried everything”.]

2020 — Science update: Updated the discussion of inflammation with important perspective about more subtle types of inflammation in overuse injuries. [Updated section: Treating for inflammation: is there any point?]

2020 — New content: A minor but nice addition of information (and a story) about heels and heel lifts. [Updated section: Orthotics.]

2020 — Minor update: Added a couple small but good clarifications, and an amusing bit of perspective, in my never-ending quest to effectively explain the importance of rest. [Updated section: Rest first: The key to tough cases.]

2020 — New sub-topic: Compared and contrasted oral and injected corticosteroids. [Updated section: Steroid injections are powerful, but where would you put the needle?]

2020 — Added sub-topic: Expanded the scope of the section to include soft bracing as well as taping and strapping. [Updated section: Taping, strapping, and bracing for patellofemoral pain.]

2019 — Expansion: Previously this chapter was just about massage in general and foam rolling in particular. I’ve widened the scope to address the underlying assumption that there’s a need to “loosen” the quads, and now cover both stretch and massage. [Updated section: Loosening the quads with massage and/or stretch.]

2019 — Minor addition: Added a brief discussion of an important principle: exercise is a pain-killer! Sometimes. [Updated section: 2. Common Resting Pitfall No. 2: Being fooled by delayed pain.]

Archived updates — All updates, including 92 older updates, are listed on another page.

2003 — Publication.



  1. Clarsen B, Krosshaug T, Bahr R. Overuse Injuries in Professional Road Cyclists. Am J Sports Med. 2010 Sep. PubMed 20847225 ❐
  2. Taunton JE, Ryan MB, Clement DB, et al. A retrospective case-control analysis of 2002 running injuries. Br J Sports Med. 2002;36(2):95–101.

    This report on two year’s worth of injuries among Vancouver runners — many of whom I probably run with every day on Vancouver’s sea wall — found that “patellofemoral pain syndrome was the most common injury, followed by iliotibial band friction syndrome, plantar fasciitis, meniscal injuries of the knee, and tibial stress syndrome.”

  3. Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75:194–202. PubMed 17263215 ❐ PainSci Bibliography 56699 ❐ “ … although management can be challenging, a well-designed, non-operative treatment program usually allows patients to return to recreational and competitive activities.”
  4. As we’ll discuss in detail below, most “basic” physical therapy for PFPS consists of minor interventions of dubious value — mostly corrective exercises, stretching, ultrasound, taping and strapping — yet the clinical impression of most professionals is that mild patellofemoral pain does go away with conservative advice. The most likely explanation for this — and it’s a common “problem” in physical therapy — is simply that most of those cases would have gotten better regardless of the therapy. Of course, in some cases, some good advice may be mixed in with bad advice, and that may help. And there may be some placebo effect: being therapized really does help a lot of people to feel better, regardless of whether or not the therapy makes any sense, and yes this phenomenon can occur even with something as seemingly un-psychological as knee pain! See Moseley.
  5. It is mostly a temporary condition: they recover from or grow out of more easily than adults do. Although serious cases certainly can and do occur in teenagers, their age is not particularly relevant to those cases. A serious case in a teenager has to be handled in pretty much the same way that you would handle a serious case in an adult. So although age is a factor I haven’t focused on, everything that I have focused on should be of interest to teens with persistent knee pain.
  6. In 2010, the Journal of Bone & Joint Surgery reported that “the quality and content of health information on the internet is highly variable for common sports medicine topics” — a bit of an understatement, really. Expert reviewers examined about 75 top-ranked commercial websites and another 30 academic sites. They gave each a quality score on a scale of 100. The average score? Barely over 50! For more detail, see Starman et al. This reference is getting old, but nothing has really changed. 😜
  7. Grant HM, Tjoumakaris FP, Maltenfort MG, Freedman KB. Levels of Evidence in the Clinical Sports Medicine Literature: Are We Getting Better Over Time? Am J Sports Med. 2014 Apr;42(7):1738–1742. PubMed 24758781 ❐

    Things may be getting better: “The emphasis on increasing levels of evidence to guide treatment decisions for sports medicine patients may be taking effect.” Fantastic news, if true! On the other hand, maybe I should be careful what I wish for, since my entire career is based on making some sense out of the hopeless mess that is sports and musculoskeletal medicine …

  8. The science of this controversial claim will be discussed in great detail below.
  9. Doctors lack the skills and knowledge needed to care for most common aches, pains, and injury problems, especially the chronic cases, and even the best are poor substitutes for physical therapists. This has been proven in a number of studies, like Stockard et al, who found that 82% of medical graduates “failed to demonstrate basic competency in musculoskeletal medicine.” It’s just not their thing, and people with joint or meaty body pain should take their family doctor’s advice with a grain of salt. See The Medical Blind Spot for Aches, Pains, and Injuries: Most doctors are unqualified to care for many common pain and injury problems. Especially the stubborn ones.
    Cartoon of a man sitting in a doctor’s office. The doctor is holding a clipboard with a checklist with just two items on it: stress related and age related. The caption reads: “An extremely general practitioner.”
  10. Sports medicine specialists are probably the least of all evils — although no professional category seems generally well-informed about PFPS, you probably stand a somewhat better chance of getting competent help from a sports medicine doctor than from any other kind of health care professional. Although they are more or less as prone to the toeing the line of conventional wisdom as any other health care professional, at least their expertise is directly concerned with non-surgical management of conditions like PFPS — and so there is at least some respectable chance that a doctor in this speciality will have paid some attention to the scientific controversies.
  11. Orthopaedic surgeons are surgeons — not only do surgeons strongly tend to perceive musculoskeletal problems only in terms of surgical solutions, but they are (quite correctly) professionally preoccupied with their surgical expertise and professional development, which means that they are typically not knowledgeable about conservative physical therapy methods for relatively minor overuse injuries like PFPS. Many of them certainly try to make a professional point of avoiding the overprescription of surgery, but that doesn’t necessarily make them experts in what to do instead of surgery. And PFPS is a particularly bad problem to take to a surgeon for the simple reason that, among knee injuries, PFPS is just about the last one that you’d want to operate on. This will be fully explained as we continue with the tutorial.
  12. Surgeons often oversimplify patellofemoral pain syndrome as simply a case of “arthritis” of that joint, and recommend a debridement (filing or smoothing) of the knee cartilage, either of the patellofemoral joint, or of the main joint between the tibia and femur (which is particularly irrelevant to patellofemoral pain). However, debridement has been proven to be ineffective even for arthritis (let alone PFPS, which isn’t arthritis), originally and most spectacularly by Moseley in 2002, then most authoritatively by The Cochrane Collaboration in early 2008 (see Laupattarakasem), and most recently by New England Journal of Medicine in September 2008 (see Kirkley). This is one of the most straightforward scientific slam dunks in surgery research in recent history — surgical debridement doesn’t work!
  13. There are more misspelled searches for this than any other topic on this huge website. A lot more. Femoral patella syndrome, patellar femoral, patellafemoral, femoropatellar syndrome! Those are the actual four most common, and there are many more, and much worse: patel, patlofemal, patalafremerol, fermopaltela, etcetlero! Both “petalla” and “femoral” are easy to get wrong independently, and when people try to merge them… well, it’s a spelling meltdown.
  14. Reid DC. The myth, mystic and frustration of anterior knee pain. Clin J Sport Med. 1993;3:139–43. PainSci Bibliography 56702 ❐
  15. Wilk KE, Davies GJ, Mangine RE, Malone TR. Patellofemoral disorders: a classification system and clinical guidelines for nonoperative rehabilitation. Journal of Orthopaedic & Sports Physical Therapy. 1998;28(5):307–322.
  16. Juhn MS. Patellofemoral pain syndrome: a review and guidelines for treatment. Am Fam Physician. 1999;60(7):2012–2022. PainSci Bibliography 56687 ❐
  17. A one-minute excerpt from his 2008 stand-up show Chewed Up is embedded below, but you can also watch the full segment (2:30) on YouTube. Funny stuff!
  18. Näslund J, Näslund UB, Odenbring S, Lundeberg T. Comparison of symptoms and clinical findings in subgroups of individuals with patellofemoral pain. Physiotherapy Theory and Practice. 2006 Jun;22(3):105–18. PubMed 16848349 ❐ In this study of 80 patients with a diagnosis of PFPS, with all other likely diagnoses already eliminated from consideration, signs of pathology were found in only 17 of 75 patients, and the authors conclude that even these “cannot be detected from ... commonly used clinical tests.” That’s quite a few mysteriously painful knees.
  19. Piva SR, Fitzgerald GK, Irrgang JJ, et al. Associates of physical function and pain in patients with patellofemoral pain syndrome. Arch Phys Med Rehabil. 2009 Feb;90(2):285–95. PubMed 19236982 ❐

    Researchers tested 74 patients diagnosed with patellofemoral pain syndrome for the presence of several factor that are commonly suspected to be associated with that condition, the “usual biomechanical suspects”: muscle weakness and tightness, coordination, and postural and anatomical abnormalities. They also considered psychological factors, which is quite unusual for a study of knee pain.

    They found no correlation at all with between the biomechanical factors and chronic anterior knee pain.

    Interestingly, the researchers did find that “psychologic factors [anxiety and fear-avoidance beliefs about work and physical activity] were the only associates of function and pain in patients with PFPS.”

There are 298 more footnotes in the full version of the book. I really like footnotes, and I try to have fun with them.

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