Saturday, October 29, 2011

One Reason I'm So Optimistic About the Ability of Knee Cartilage to Heal ... that (as I've written before), in this medical study, cartilage did appear to heal, and at a surprisingly high rate: 37 percent.

What's more, that figure almost certainly under represents the true rate. I'll get to why in a moment (the why is the reason for this post). The explanation is a bit wonky, but well worth the effort to understand.

First though, that tantalizing 37 percent. What does that mean? That 37 percent of all subjects with bad cartilage were totally healed by the end of the study (two years later)? Nope. Sorry, but nothing so dramatic. Rather, it means that 37 percent of the subjects experienced an improvement in a cartilage defect somewhere in their knee.

Ahah. Now we're getting somewhere. But still -- what's an "improvement in a cartilage defect"? Well, first, areas of knee cartilage were examined by MRI. Then a common scoring system was used to evaluate the tissue, where "0" is normal, "2" is some wearing away with at least 50 percent thickness remaining, and "4" is eroded to the bone (so you have five possible scores: 0, 1, 2, 3, 4).

So for your right knee, for example, you may have a spot that's graded "4" (no cartilage), and at the end of your tibia a place that's a "3," and then a location on the inside of your femur that's a "2." Two years later, the defects were reviewed again. A difference in the score was either an improvement or a worsening, depending on which way the number changed.

Up to this point, you may be thinking you've already read on this blog about the 37-percent-of-defects-healing study, so what's new? Answer: the 37 percent number is almost certainly not accurate. It's too low! "Why" is something I discuss in the book, but have never written about on my blog.

So let's delve into the reason. First, you have to appreciate a subtle truth about measuring rate of change: the amount of change that you find always depends on the accuracy of the measuring instrument.

Confused? Well, in Saving My Knees, I illustrate why this is true with a hypothetical world where you can determine people's heights using only devices that measure in increments of one foot. In this population, everyone has a height of 1 foot, 2 feet, 3 feet, etc. There are no inches.

Suppose you have three teenagers: Mary, Ted, and Fred. Mary (according to our Earth measuring tape) is 5' 6", Ted is 5' 9", and Fred is 5' 11". A study is undertaken to see what percentage of our three subjects grows over the course of 12 months. After a year, Mary is 5' 7", Ted is 5' 9.5", and Fred is 6' 1".

What percent of the population has grown, if we're measuring them with a device that has only feet, and no inches?

Only 33 percent! (Fred was "6 feet" before, because he was between 5 and 6 feet in height, so now that he's between 6 and 7 feet, he's considered 7 feet tall.) What about Mary, who grew an inch? No, she didn't grow at all using our rough measuring stick -- she went from 6 feet to 6 feet. No change. Same for Ted.

Seems crazy, huh? But that's what you get when using an imprecise measuring device.

Now what happens when you measure the difference in cartilage defects using only five grades? You're going to miss change that you would capture were you able to use 10, 20, or 50 grades. Consider: Cartilage at a given location that has worn 95 percent away is rated a "3." Two years later, if that same location is 55 percent worn away, that should be considered an improvement, right? But 55 percent still falls within the classification of a grade "3" defect. So, using this crude measuring system: no change!

If it were possible to make finer measurements with confidence, we'd expect to see a higher rate of change, all else being equal. Take a moment to ponder that. Once you fully grasp the implications, you'll never look at a study that involves rate of change the same again.

What I've explained above, you don't need an MD to understand. This isn't knowledge that's privileged to the cognoscenti of the field, who have examined thousands of knees. This is simple math and logic. But what's the main takeaway?

This: Cartilage is a dynamic tissue, often changing for the worse -- and for the better!

Insert thunderclap here. Because, honestly, too often changes in knee cartilage are seen as a one-way (downhill) process. But that doesn't accord with the reality discovered in this study (and there was another that found similar evidence that defects often improve).

Cartilage is constantly trying to heal: that's what this study suggests to me, when you explore the ramifications. And that should give you encouragement on the long road to recovery.

Friday, October 21, 2011

If You're Overweight and Have Knee Pain, You Need to Read This

Below are my top four recommendations for people who are overweight and who suffer from chronic knee pain:

1. Lose weight.

2. Lose weight.

3. Lose weight.

4. Lose weight.

No, I'm not trying to be clever here.

I'm convinced that controlling one's weight is critically important for overcoming knee pain. It's not an instant miracle cure -- after losing 30 pounds, you may not be able to leap up and shout, "Hallelujah, I'm healed" (you still need to work at it), but you'll be in a much better position to succeed.

If you don't believe that excess weight can have a huge effect on knee health, well, there's the anecdotal evidence.

For example, take a look at the picture below that ran with a newspaper article about aging baby boomers and knee surgery. This woman had a total knee replacement. Does anything jump out at you?

Obviously, she's nowhere near her ideal weight.

Here's another bit of anecdotal evidence to mull over: some months ago, while browsing the comment section below an Internet article about knee problems, I was struck by a remark posted by an orthopedic doctor. His comment went something like this: "In all my years of practice, I've never had a patient who had osteoarthritis of the knee who was also thin."

Of course there are thin people with knee pain and/or osteoarthritis (I was the former). But the fact that a doctor who sees dozens of patients a week would make such a comment tells you that they're more the exception than the rule.

The relationship between carrying around too much weight and knee problems doesn't surprise me. During my research for Saving My Knees, I was impressed by how human knee cartilage has made a lot of neat adaptations -- related to obtaining nutrients, dumping waste products, growing stronger -- based on movement and load (i.e., weight). The right amount of loading encourages the tissue to strengthen. Excessive load starts to break it down.

Researchers know this weight-knee pain link exists. During my recovery, while reviewing scientific studies about knee cartilage, I noticed the first thing that researchers did when organizing the results was separate the heavy subjects (higher BMI) from the thin ones. Which is basically a way of acknowledging that of course extra pounds put you at higher risk, so to keep the results relatively clean (and unskewed by this variable), the large people should be segregated out.

What if you can't lose weight? A while back I read a complaint from a girl with knee pain that went like this: "Don't tell me to lose weight! Every time I try to exercise in order to lose weight, my knees hurt!"

Ahem. Reality check. While it's certainly easier to lose weight through vigorous exercise, the best exercise is the one you don't do: repeatedly raising your hand to your mouth to insert food. Eat smarter, better, healthier, and you can lose weight. I managed to do so while living in Hong Kong, and that was at a time when I really had no extra weight to lose.

Saturday, October 15, 2011

Why I Think Cycling May Be the Best Activity for Rehabbing Bad Knees

A bold claim! And somewhat ironic, I suppose, as readers of Saving My Knees know I damaged my knees cycling and was unable to ride my bike again for many months, even as I plowed forward with my recovery. So in my case, I got better largely off the bike.

Also, time for the disclaimer dance: I don't think cycling is the best activity for everyone suffering from chronic knee pain. It's dangerous to generalize in the world of knee pain, because different knees often respond best to different things.

For example, one thing needed to ride a bike: good range of motion. If, every time you push your bad knee through the pedal stroke, you experience a painful clicking, or some other type of discomfort that recurs with each revolution, cycling most likely isn't a good activity for you, at least right now. That's partly because good cycling form is about spinning, or making lots of revolutions, every minute (Lance Armstrong, if I recall correctly, used to time trial at 110 rpms -- try doing that on a stationary bike and watch your legs fly!) So you need a decent range of motion that your knees can move through without hurting or "catching" too much, because they will be repeating that motion, again and again and again.

Okay, now that the big caveats are out of the way -- why am I such a big fan of cycling for bad knees?

(1) You want a high-repetition, low-load activity. That's exactly what easy cycling is.

Notice the word "easy." No hills, no sudden accelerations! A moderate rate of spin will get you 80 rpm on a bike -- that means you're flexing your knees 800 times in 10 minutes, or 2,400 times in half an hour. If your cartilage needs thousands of repetitions to spur positive adaptation (i.e. strengthening), this is an ideal exercise, it seems.

(2) Cycling is not a "bone accretive" activity.

If you need stronger, denser leg bones, one activity that won't be prescribed for you is cycling. Riding a bike is a low impact form of exercise that uses a smooth, fluid stroke. It doesn't build up bone mass. (Which leads to the paradox that the cyclist with the heavily muscled thighs who just blew by you on your daily walk may have lousy bone density.)

That can be a good thing, if you've got bone spurs in your knees already from arthritis, which is common with chronic knee pain. Bone spurs can interfere with the normal movement of a knee joint and can be an impediment to the healing of cartilage (as shown in this study: Ding C. et al., “Natural History of Knee Cartilage Defects and Factors Affecting Change”). Cycling should help you strengthen the soft tissue without promoting the formation of unwanted bone.

(3) It may cause your knee cartilage to thicken.

When the knee cartilage of triathletes was studied, an interesting discovery was made. The patellar cartilage was slightly thicker than normal (Muhlbauer R. et al., "Comparison of Knee Joint Cartilage Thickness in Triathletes and Physically Inactive Volunteers Based on Magnetic Resonance Imaging and Three-Dimensional Analysis"). Assuming this was a solid finding that will be reinforced by other studies, what might it tell us?

Well, triathlons generally consist of three activities: swimming, running and cycling. I doubt that swimming, in particular the overhead crawl stroke that you'd expect a triathlete to be doing, promotes the formation of more cartilage under the knee cap. Nor would I expect running to achieve this effect, with its harsh impacts absorbed mainly by cartilage at the end of the leg bones.

Cycling appears most likely to be responsible. Just look at the angle of the knee during the force-exerting part of the pedal stroke. Hopefully future studies will clarify whether cycling does encourage cartilage growth.

(4) Strong quads!

Anyone who reads this blog regularly may be thinking, "But wait a minute -- aren't you the guy who thinks focusing on strong quads is a mistake for people who have chronic knee pain?"

Yup. That's right. But these are two different things.

Having strong quads is great and surely does protect against developing knee pain. Acquiring strong quads through exercise, when your knees tolerate that exercise well, is also great. What doesn't make sense to me: Focusing on strengthening your quads when your knees are damaged and weak and the quad-strengthening exercises only cause more pain.

One nice thing about a cycling program, if you're patient, is that the gentle cycling that you start out doing, to heal your joints and strengthen your knees, can gradually be intensified to the kind of workout (which I do now) that will really develop your quads. Trust me, I know. :)

Saturday, October 8, 2011

Reasons Why You Should (or Shouldn't) Keep a Knee Journal

In Saving My Knees, I described my experience keeping a knee journal, and how it helped me. Since then, I've been flattered to learn that at least a few readers of the book have chosen to do the same.

Perhaps one day knee journaling will even be widespread. While excited by this possibility (an idea goes viral in the knee pain community!), I also feel a little trepidation. That's because I can imagine some people taking up the activity with a half-hearted shrug -- "Ah okay, I'll give it a try, what the heck" -- then losing interest some weeks later, muttering, "Well, that was a waste of time."

So I thought I'd write about what makes a useful knee journal, in my opinion. Note at the outset, I'm saying "in my opinion." You may feel otherwise. If you want to include the dates of lunar cycles and observations about local flora and fauna, well, hey: It's your knee journal.

Still, I think the best use of such a journal is to pretend you're a scientist, you've just been given these things called "knees" that don't work all that well (and which unfortunately have been implanted in your body), and you're undertaking a study to try to determine what makes them feel bad, what makes them feel good, and how you can transition from the first (undesired) state to the second.

With that objective, a knee journal becomes a place not to kvetch aimlessly about your aching joints ("Ah, another miserable day in the wretched land of knee pain, as I regard the wind-swept fields from my balcony!"), but an aid to healing. Your knee journal should be working for you, not lying there passively to record random thoughts about your pain. How?

(1) If you use a knee journal smartly, it should give you a fairly detailed picture of where you are in your recovery and what your knees can and can't do.

If you're trying to heal your knees on your own, you face at least two big challenges: (a) figuring out a "baseline" level of activity your knees can handle, without getting worse (b) figuring out how much and you quickly you can push beyond this baseline, in an attempt to strengthen the soft tissues in the joints.

A good knee journal can help because you should be wearing a pedometer (mine was practically bolted to my hip) and scoring, or otherwise quantifying, how your knees feel day to day (and throwing in notes about your daily activities and the nature of the pain sensations from your knees).

(2) As you experiment, trying to find the right exercises to do, in the right amount, a knee journal provides invaluable feedback. (Note: a big benefit of working with a good physical therapist is that you shouldn't have to experiment nearly as much.)

I often tweaked my regimen, such as by introducing a new type of exercise that I thought might help. Later, I could look back in my journal and get a sense of what effect that exercise had, good or bad.

(3) Inspiration!

So there is a soft, fuzzy reason to keep a knee journal after all. :) There were times (after the first three or four months of my recovery program) when I was discouraged and felt I hadn't made much progress at all. My knee journal lifted my spirits by showing me that yes -- even though progress was slow -- I was getting better. I could look at entries and summaries from my first few weeks, and see my limitations then, and be grateful I had gotten beyond some of those problems at least!

Saturday, October 1, 2011

How to Heal Bad Knees: A Reader Shares a Story

I'm going to get off the soapbox this week (I had planned to write about the purpose of keeping a knee journal -- I'll save it for next time) because I found a wonderful story waiting for me in the comments section of a past post.

So I'd like to turn the podium over to this unnamed commenter (with a few of my remarks at the end):
A few years ago I too was diagnosed with patellafemoral syndrome (chondromalacia of patella) and was only able to shake it after reading Doug's blog on articular cartilage. Like the above emailer, mine was so bad I couldn't walk for more than a minute or two without increased pain.

So here's what I did:
1)crutches with no weight bearing on affected leg for 3 days.
2)crutches with putting some weight (maybe 50%) on my affected leg for another 5 days. By now the knee was largely pain-free, but I could tell if I did too much it would start hurting again.
3)took it easy for the next couple of weeks by only walking for a few minutes per pop, made sure when on stairs to only take the initial step up with my good leg.
4)built up my walking stamina and using both legs for stairs over the next 5 months. was back to running at month 6, doing the couch to 5k program. A few years later now, and I'm back to marathon training, 100% pain-free knee.

Now, I also had a 40 hour/week desk job during this ordeal. I basically just made sure to flex and extend my knee (pain-free range, which started off with maybe 10 degrees of movement!) every few minutes on a small bosu ball I brought to work (like Doug's skate board recommendation). I also lightly (10% of strength) pushed my foot into the floor or wall of cubicle starting at about 100 times a day, up to 1000 times (and built up the pressure used as long as it didn't hurt the next day). I also did squats at around 4 weeks, but did them with reduced weight bearing (kind of like dips for your chest but with my feet on the ground), and not to sound like a broken record, but built up my weight bearing on this as well.

I'd be interested to try my experiment again without the use of crutches - maybe my decreased weight bearing, high rep exercises would've been enough.

By the way, I was so psyched by my results and by Doug's blog, I decided to switch careers; now I'm just a few weeks away from graduating from PTA school.
Beautiful story -- I love it, especially the crowning touch "now I'm just a few weeks away from graduating from PTA school." Because we need more physical therapists who are this smart about healing chondromalacia-related knee pain!

What this person did reminds me a lot of my own recovery: doing lots of high-repetition, low-load movement. Pushing the envelope on the exercise program, but very slowly, so as to get stronger while avoiding a relapse. Carefully monitoring for symptoms -- not during exercise or 15 minutes later, but the next day (your damaged cartilage has no nerve endings, remember!). Overcoming the ultimate "bad knee environment," the white-collar workplace (I finally had to quit my 50-hour-a-week job; I congratulate this commenter on resolving the problem of prolonged bent-knee sitting through doing quiet exercises in the cubicle).

That this person could return to running in six months struck me as impressive. My objective was to ride my bicycle again, pain free, and it took me more than 13 months to achieve that. Anyway the upshot is the same: healing from chronic knee pain has to be measured in multiples of months (five or six at least), so patience is needed.

Your aching knees can heal! It's not just my story anymore; I'm convinced there are many more happy stories out there too, and my fervent wish is that someday -- SOMEDAY -- the medical community will become curious enough about how cartilage heals naturally to launch some good studies that will lead, hopefully, to a revision of the gloom-and-doom thinking about the outlook for patients with chronic knee pain.