Does Thinner Cartilage Cause More Knee Pain?

Here’s a study that could be of interest, as it casts doubt on the relationship between cartilage loss and knee pain.

The researchers found that a thinning of cartilage was associated with only a modest increase in knee pain. The writeup was published in the Annals of the Rheumatic Diseases.

There were 600 subjects who either had, or were at risk of, osteoarthritis of the knee. MRIs were taken of their knees at the outset, after one year, and after two years, then the images were compared.

Loss of cartilage thickness was significantly associated with a small degree of worsening knee pain over 24 months.

David Felson, one of the researchers, did note that an “indirect path” exists between cartilage loss and knee pain. The relationship could be through nerve-rich structures, such as the synovium and bone marrow.

Good news, right?

My first inclination is to say: sort of.

I wonder if the condition of the cartilage is more significant than the thickness. If the cartilage is thinner, but is stiff enough to absorb shocks well, it seems logical that someone would not feel pain.

But, to be fair, there is good news here. The welcome implication is that you don’t have to restore your knee cartilage to normal for your pain to go away.

Finding the Numbers to Your Combination Lock

I went on a 103-mile bike ride yesterday -- phew! Some say it's not the heat ... but yes, it's the heat! It's hard to stay properly hydrated when the temps climb into the upper 80s. This morning I'll be in the basement, riding the stationary bike, trying to make up for the fact that yesterday's ride burned up most of my day.

Now then, here's a reader comment that put me in mind of something Dr. Scott Dye once said:

I have no idea what is the matter with my knees, have had no diagnosis and have kind of given up on that front, though I'm convinced it started mentally as i was suffering from chronic stress at the time, I also have a raised vein or nerve in leg so could be that WHO KNOWS. They do improve a lot with motion though, and lately on my walks ive just had the urge to start gently jogging, its like my body wants to take off, whats your advise on that? I havent jogged but i really want to.

Here's what Dr. Dye said that I found to be very true, though curious coming from a physician. It concerns the difficulty of finding the right program to heal a person's bad knees:

“It is not unlike trying to find the numbers to a combination lock.”

We tend to naturally attribute shaman-like qualities to our doctors, believing they have an almost magical power to heal us. How strange it is, then, to hear a doctor compare what he's doing to cracking a safe. It's perhaps a bit unsettling. Aren't doctors supposed to be supremely confident in their diagnoses?

But I think Dye's observation is quite perspicacious. He nails it. The fact is, there is no manual on healing knees that will work equally well on all knees. A certain amount of experimentation is in order.

Partly I have come to that realization from listening to all of you while writing this blog. As I've said before, I wrote my book naively assuming that what I did would be useful to the same degree for everyone. I still think the book has enormous value, and broadly the approach is the correct one, but I've also tempered my position somewhat, so that now I'm closer to Dye's thinking:

Healing your knees will involve finding a solution that will probably be, to some degree, unique to your particular knees.

So why does this reader comment put me in mind of Dr. Dye?

Because here's someone who has bad knees, it appears, but who wants to "start gently jogging." How could that be a good idea?

But suppose this person is right: that stress contributed to the knee issue in the first place. Maybe a little gentle jogging, getting the heart pumping and the body sweating, would help lower his stress levels -- and it might not be harmful to his knees too.

Maybe?

I am opposed to giving advice, but if I were this person, I might try an experiment: maybe try a short jog, very slow, maybe up a hill as that's less stress on the joints, and then monitor my knees for a couple of days. Do they feel better or worse?

If they feel better, maybe try it again, for a little longer, being careful of course and not pounding down hills.

Do I think this would have helped with my own knee pain? No, not really. But then again, if we are all trying to find the numbers to our personal combination locks, when it comes to beating knee pain, we have to be open to trying different things.    

A Goldilocks Theory of Cartilage Damage

Here’s a study I can’t access (without paying for), but I found the main conclusions interesting. The researchers decided to look at the following:

Knee cartilage damage is often linked to mechanical overloading. However, cartilage requires mechanical load to remain healthy, suggesting that underloading may be detrimental.

So there you have it. Essentially, they’re testing what we’ve talked about repeatedly here: trying to find a motion “sweet spot,” if you will. If you subject your knees to too much load, they will get worse. If you don’t subject your knees to any load, they will get worse too.

The key is finding that elusive “sweet spot” where they can handle the proper amount of load, which can be gradually increased over time. However, of course, this is no simple thing.

So what did the study consist of?

The researchers looked at how the load on a person’s knees correlated with worsening cartilage damage over a two-year period. There were 964 subjects, including 62% women. The average age was 66.9 years old, and the average BMI 29.7 (this borders on obese and roughly equates to weighing 220 lbs. for someone who is six feet tall).

People who walked a moderate or high number of steps each day (at least 6,000) and who had a high BMI (more than 31) had a greater risk of worsening damage of the cartilage in the medial part of their tibiofemoral joint, compared with those who were thinner.

But people who walked less than 6,000 steps a day and who had a low BMI were at higher risk of worse damage in both the medial part of the tibiofemoral joint and lateral (outside) part of their patellofemoral joint (where the kneecap meets the femur). They were compared to a group that also had a low BMI but walked more steps.

Clearly, one takeaway is that weight has a big influence on how much walking you can safely do.

But the results also do suggest that there is an optimal level of motion: too much will cause further damage, and not enough is harmful too.

The trick is finding that proper balance. What’s scary for people with bad knees is that finding that balance becomes a really hard task when your knees don’t seem to like to move much at all.

It will frustrate you endlessly, I guarantee. But when you do figure out the right balance, you are suddenly in a position to get better, slowly but surely.

And that's a great feeling, when you realize you're starting to make progress toward healing.

Knee Pain Recovery: When to Return to the Sport You Loved?

Someone left this question recently (edited for brevity):

My side question to you is, how/when did you decide cycling was reasonable to try again? It has been 2+ years since I have been on the bike. My knee pain/symptoms have improved. I can now go on 2 mile walks, use a rowing machine for 15 min, even do gardening & housework. Of course if I overdo it, my knees will remind me and I can have a setback. So day to day life is so much better than two years ago, so I don't want to risk losing that. ... What was your indication that gave you confidence to try cycling again?

Viewed narrowly, this is a question about cycling. When can someone return to cycling after a bout with knee pain? But I think it’s a question that could be asked more broadly: During your recovery from knee pain, when is it appropriate to return to your favorite sport, “x”? (Here’s more musing on that question by the way.)

Answering this should force you to confront an unpleasant question: Was sport x somehow involved in your developing knee pain? Chances are it was. And when that’s the case, you might have to be even more careful about returning to that activity.

For me, cycling was something I really loved. I loved the intensity of the workouts, climbing hills and pushing myself to the limit, trying to set personal records on courses. I also knew I was a pretty good rider – nowhere near good enough to ride with the best, but competitive on a local level.

After developing knee pain, I had a tough time giving up riding my bike. A few times, when my knees felt a little better, I would get back on the bike, thinking, “Maybe, just maybe, they’re fine now.” Of course they weren’t, and a few minutes later I would get off the bicycle, miserable, wondering if my knees would ever heal.

Finally, I reluctantly gave up cycling. I said, “I just can’t do this and get better.”

For me, getting better was partly about accepting a grim truth: I might never be able to ride my bike again. In fact, I think it’s almost easier if you manage to convince yourself that that part of your life is history. When you accept that, you’re not always trying to climb back on your bike on the first day you have pain-free knees.

But at some point, I did of course.

It was after I returned to America from Hong Kong. I knew my recovery was well in hand, and I felt confident it was just a matter of time before my knees were normal again.

I can’t tell you I reached this decision about returning to cycling after x weeks of no pain from my knees, or after two months of being able to do x. Heck, I don’t even remember now.

What I do recall about the decision: As I said, I had pretty much given up on cycling, after failing on multiple occasions to ride without triggering the burning in my knees. Instead, I was just focusing on getting better. And, at some point, when I felt like my knees were really stronger, and that I wasn’t at risk of backsliding, I rolled the bike out, took a deep breath, and went on a very, very slow ride. And my knees were fine.

Open Comment Forum: What Was the Biggest Mistake You Made?

Of course the normal open comment forum rules apply: Feel free to ignore my suggested topic, and talk among yourselves about whatever you'd like.

But for anyone who wants to go along:

What was the biggest mistake you made when it comes to managing or dealing with your knee pain?

This is probably a moderately hard question. I pondered it myself. I couldn't think of a single event.

As in, I can't really say, "The biggest mistake I made was seeing Doctor X and taking his advice to do Y."

Rather, I think the biggest mistake I made was not taking my knee pain seriously for months, and assuming it would go away, because I was healthy and had always recovered well from minor injuries.

By the time I did take it seriously, I was in a really deep hole. And then, at that point, unfortunately I kept digging that hole. I knew I had a problem with knee pain. I knew it wasn't going to magically resolve itself. But still, I tried to keep semi-active. I stressed my knees more than they could handle.

Then, finally, I hit that low point where I conceded how bad things were, and with that knowledge, I could chart a path to recovery.

What about you? What was the biggest mistake you made?

Anyone Want to Talk About Using a Walking Desk?

I got this comment recently. Lately I have been trying not to sound like a broken record (it feels like I've written about so many topics already on this blog), so I've been sifting through the comment section for ideas for new posts.

Richard - Thank you for publishing your experience and being a resource for us. I've been dealing with pfp for 2 years and it's when I'm sitting at my desk that it's worst. Recently I fashioned a DIY cycling desk at my apartment, which has been effective but nothing helps as much as walking. Curious if you, or others, have invested in a walking desk?

Anyone want to share their experience with a "walking desk"?

I was curious about walking desks -- no, I've never used one -- so I did a quick Google search. They look like a treadmill married to a small, simple table at the proper height. See here for an example.

Hmm. Looks interesting. Prolonged sitting is poison after all, right? I really do believe that.

So here are a couple of quick thoughts from me about "walking desks," and I warn you again: this is coming from someone who has never tried one:

* They look like an interesting idea for people who are already fit. I noticed that in the images that Google brought up, most everyone pictured looked like they could go out and run about 5 miles, no problem.

* For people with bad knees, I'm not so sure, but I guess it depends on how bad your knees are. They remind me too much of my early failed experiment with walking constantly, after I realized that the key to rehabbing bad knees was motion. But I overdid the walking. In a big way.

* So with a walking desk, what happens when you need to take a break? After a while you will get tired. Your muscles will be tired. Your feet will be tired. Maybe your knees will be tired too. Do you shift over to your non-walking desk nearby? Or are you supposed to be walking for an entire eight-hour day? Not sure I'd be keen about that.

Who out there has tried a walking desk, or a similar setup? Want to share what you learned?

When Your Doctor/MRI Speaks a Foreign Language

I got this comment recently:

Hi Richard, not sure if you have any suggestions or experience on exercises or treatments regarding diagnoses of focal chondrosis, narrowing of the patellofemoral joint, subluxed patellas or joint effusion?

Well, that's a mouthful certainly. What's all this clinical jargon mean? (And why do medical technicians and professionals always speak in some baffling foreign language?)

Anyway, here's my take. If I'm wrong, someone feel free to correct me, but I think I'm in the ballpark:

"Focal chondrosis" appears to be simply a loss of articular cartilage. "Focal" suggests a particular location (or locations).

"Narrowing of the patellofemoral" joint is what it sounds like, and was perhaps seen on an X-ray. If there's loss of your protective cartilage, an X-ray will simply detect that the joint space has narrowed. That's because the cushioning cartilage has thinned, showing the bones closer together. Remember: an X-ray can't actually see the tissues, so basically someone infers what's going on based on how far apart the bones are.

"Subluxed patella" seems to be a patella that's mistracking or becoming partially dislocated. On this point, I'd be curious. Is this something that's just been "clinically observed"? Or what exactly is the evidence of this?

There are plenty of reasons to be skeptical when it comes to the role of patella mistracking when it comes to knee pain. See here, here and here, for instance.

And finally we have "joint effusion." "Effusion" is just swelling. So you've got swelling in your joint. D'oh! No big revelation there, I'm guessing.

At this point, what exercises might be suitable?

Well, "effusion" suggests that the joint is being stressed beyond what it can handle. That means that, whatever exercise regimen you choose, it should probably be fairly easy, at least in the beginning.

As for the cartilage loss, this bears repeating: cartilage loss, by itself, doesn't have to be a sentence of knee pain and misery. It does often correlate with knee pain and misery, true. But someone can have knees that feel healthy while having pockmarked cartilage.

What exercises are good for these conditions? You might want to consider activities that slowly build the strength of the remaining cartilage. They could be low-load, high-repetition. And, of course, you want them to be easy (see "joint effusion" above).

Finally, what about the "subluxed patella"? Hmm. A couple of quick thoughts:

(1) It's not really medically significant, even though some misguided doctor/physical therapist thinks it is. In that case, you might want to just try the light-load, high-repetition, and see how it goes ...

(2) It is medically significant. In that case, honestly, you might not get any satisfactory results apart from surgery. "Muscle strengthening" programs probably won't do the trick.

So those are a few thoughts. Others are welcome to comment below. And, of course, remember: none of us has seen your knees. We're just throwing out things to consider. Your best advice, in the end, is really to see another doctor and get that second opinion.