Exercises to prevent knee osteoarthritis

[Jim Pickles]

Are there any physiotherapists reading this? I’d appreciate hearing from them as well of course from the ST community.

One of my students (56 yrs old) has revealed that she has knee osteoarthritis (confirmed by MRI scans) in the medial cartilages of both knees. This is clearly a concern, because of the considerable chance that it will progress and she will end up needing knee replacements. Not only are knee replacements painful, but they only last about 15 years and a further operation (by which time the patient is usually very elderly) is problematic.

Because 90% of knee replacements are to the medial bearing surface in the knee, unless this cartilage has some intrinsic weakness (and there is no evidence for this), then it suggests that some of the load in walking has not been shared properly between the medial and lateral cartilages, and that the medial cartilage has taken most of the load. Therefore it has an origin in faulty biomechanics (from the reviews I have found, this seems to be the generally accepted view). Faulty biomechanics could include faulty use of the leg muscles, faulty tracking of the knee joint in walking, faulty alignment of the foot (e.g rolling out, attempts to correct pronation), etc.

If faulty biomechanics causes a problem that can escalate to catastrophic levels, it seems to me that it correct biomechanics should be introduced as early as possible, and preferably used all ones life – and that it should be taught routinely. This is what I attempt to do with a yoga standing exercise (of which more later).

It is interesting that in my searches on the internet, there seems very little discussion of the importance of correct biomechanics in relation to this issue, how correct biomechanics are trained, and how they may be important in preventing knee osteoarthritis. Most of the attention seems devoted to dealing with patients who already have substantial knee osteoarthritis. One of the few reviews I have found is the following: Reeves ND, Bowling FL. (2011) “Conservative biomechanical strategies for knee osteoarthritis.” Nat Rev Rheumatol. 7(2):113-22. This needs a paid-for subscription, and the abstract from Pubmed is attached at the end of this message for anyone who wants to read it. As far as I can tell, this is an influential review, and many other sources on the web seem to copy its arguments (even if they don’t cite it).

Reeves and Bowling say that the main danger is that the knee joint “bows out” to the side in walking (this is also known as knee varus or knee adduction). In the midphase of the stride the weight is in the midline of the body, but the weight is taken only on one leg which is not in line with the direction that the weight is acting. If incorrect muscle action is used, the knee may bow out to the side, meaning that most of the weight is taken on the medial cartilage, which wears (see attached diagram). Apart from using prostheses etc, the main strategy seems to be strengthening of the leg muscles to stop it getting worse.

(the third diagram shows what leads to excessive force on the medial cartilage; in each case, the centre line of the body is to the right of each diagram)

If you think what the leg muscles have to do to keep the weight directed along the line of the leg during all phases of the stride it is in fact a very complicated process, and I doubt if one could explicitly describe and learn it as such. What I do in my yoga standing exercise is to encourage muscle awareness of what happens when the muscles of the leg are all lightly but evenly engaged, and that one can “feel” the ground and the weight of the body traversing the length of the leg to all parts of the foot. The encouragement is not to use minimum awareness and not to let the leg muscles get lazy (which might lead to some muscles switching off).

It seems to me that this is a very important issue and I am surprised that I have not been able to find any more resources on it. I have adapted a yoga exercise to deal with what is potentially a major medical problem. I need to know if I am using the best approach.

As for my student, the physio she had earlier who diagnosed the osteoarthritis did not suggest any corrective action, so I presume this physio’s approach would be to leave her alone and let whatever started the process off continue until it crippled her. I have instead suggested that she should go to the most experienced and wisest physio I know. I hope that correct biomechanical training will reduce the load on the medial cartilage and stop any progression of the osteoarthritis.

So my question is: what are the best exercises for normal people who do not yet show any signs of knee osteoarthritis, to ensure that they use the best biomechanics in walking, and have the minimum chance of developing knee osteoarthritis? Is a yoga standing exercise the best approach? (I can describe this if anyone wants to know the detail, but it is pretty standard, and this posting is already very long).

Thanks for your help,

Jim.

Abstract of the paper referred to: Knee osteoarthritis (OA) is one of the most prevalent forms of this disease, with the medial compartment most commonly affected. The direction of external forces and limb orientation during walking results in an adduction moment that acts around the knee, and this parameter is regarded as a surrogate measure of medial knee compression. The knee adduction moment is intimately linked with the development and progression of knee OA and is, therefore, a target for conservative biomechanical intervention strategies, which are the focus of this Review. We examine the evidence for walking barefoot and the use of lateral wedge insoles and thin-soled, flexible shoes to reduce the knee adduction moment in patients with OA. We review strategies that directly affect the gait, such as walking with the foot externally rotated ('toe-out gait'), using a cane, lateral trunk sway and gait retraining. Valgus knee braces and muscle strengthening are also discussed for their effect upon reducing the knee adduction moment.

[Kit_L]

@Jim,

So my question is: what are the best exercises for normal people who do not yet show any signs of knee osteoarthritis, to ensure that they use the best biomechanics in walking, and have the minimum chance of developing knee osteoarthritis?

Please read the whole anti-pronation thread in the light of your post (if you have not already); it is a sustained argument for how to improve biomechanics so this does not happen. IMHO, the major cause of osteoarthritis of the knee is ankle-foot pronation under load. Examination of the soles of the feet clearly show the result: callousing is the evidence of precisely which parts experience more time under load than adjacent parts of the feet—and the majority these days show this callousing only on the inside. If this is the case, then—generally—the medial side of the knee is bearing more load over any given time or activity. It wears out first. It is unnecessary, in my view.

[Jim Pickles]

Kit - thanks - yes, of course, I remember our discussions on pronation and will look out the pronation info on this site. Many thanks for your helpful reply, Jim.

[Ciaran]

So my question is: what are the best exercises for normal people who do not yet show any signs of knee osteoarthritis, to ensure that they use the best biomechanics in walking, and have the minimum chance of developing knee osteoarthritis? Is a yoga standing exercise the best approach? (I can describe this if anyone wants to know the detail, but it is pretty standard, and this posting is already very long).

Maintaining correct foot biomechanics does wonders for optimal loading of the lower limb kinetic chain. In conjunction with an anti-pronation intervention, any other methods to reduce loading of the knee are helpful in not just preventing but also slowing the progress of OA. Some methods include: reducing weight, strengthening the knee extensors, reducing pain, maintaining ROM of the affected joint.

Here is a good review of the management of OA. You shouldn't need a subscription to view it.

http://oarsi.org/sites/default/files/library/2013/pdf/part_ii_oarsi_recommendations_for_management_of_hipknee_oa_2007.pdf

Ciaran - Physiotherapy student.

[Jim Pickles]

Ciaran (or Cregan) many thanks for your reply too. I have downloaded your article which in general follows the one I mentioned earlier (which is behind a paywall). I am now getting an idea of what the established clinical view of knee OA is. I have some further thoughts which I am putting together (with diagrams I hope) which I will post here when ready.

Thanks, Jim.

[Craig]

From my perspective, making sure the knee, hip and ankles (well really all joints) get moved in all 3 planes regularly, slowly increasing load and ROM.

[JoachimG]

This blog post made me realize I need to move more because I have cartilage and meniscus damage...

I look at it like this, I can either move around and strengthen my body and possibly improve it or I can sit around and wait for my knee to degenerate anyway...

http://www.markpieciak.com/2013/10/reversing-osteoarthritis/

[Jim Pickles]

Just a quick response to JoachimG, as I'm putting together a longer response on the knee issue. Manewhile - some time ago I looked into the information on cartilage degeration in spinal discs (which are a special case in some ways).

YES, movement and pressure can help nutrients get into a cartilage and help it renew. But if it was just such a simple story, a joint which is under sustained and increased pressure (like the medial knee cartilage in many knees) would become STRONGER, and wear LESS, rather than wearing more (but we know that excess pressure in the knee causes degeneration). So the answer is not just a simple "keep the pressure on the joint" - in fact, pressure can be bad.

As far as I can tell, it is movement that is critical, and in particular cyclical loading and unloading. In fact, in some cell cultures of spinal disk cartilage (as far as I can remember) the patterns of loading and unloading as would occur in walking were the optimal ones for encouraging cell growth in the dish (I may be wrong on this; it is a long time ago that I read it).

Also as far as I remember, there is a lot of controversy about how to treat osteoarthritis. Some people think you should continue exercising through the pain, others think you shouldnt, and I guess that this reflects the complexity of the issue and individual differences. Maybe up to a point, movement and pressure strengthen, and after some tipping point, they have the reverse effect.

[JoachimG]

Thanks for the feedback Jim. Could you explain cyclical loading/unloading I dont quite understand, is it simply loading and unloading a joint?

All I know is that when I dont strength train and move, my knee feels shitty compared to when I dont..

[Jim Pickles]

Yes, just loading and unloading.

[Ciaran]

No worries Jim. My proxy from university must be getting me into those journal articles for free. If there is anything in particular you are after 'pm' me and I can most likely send you the .pdf! Knowledge and information should be minimal cost or free. That is one of the top reasons I really admire Kit compared to the other 'coaches' out there. He's not about the money (need to eat of course ), but you know what i mean.

As far as essential loading goes its relatively simple in theory but can be hard for an individual to implement due to a lack of anatomical knowledge. I strongly feel general anatomy should be a compulsory course in education (primary --> high school). It is the language of your body and unfortunately what we have seen is a detachment from mind/body in our current culture (perhaps mostly Western culture).

Sorry, back to the loading! Cartilage generally has poor blood supply and it is the cyclic loading/deloading which is essential for recycling/replenishing the necessary nutrients needed for it's primary function. What we see is very unconditioned people, with poor body awareness, moving from a sedentary lifestyle to a more active lifestyle resulting in injuries. The solution seems to be to just get off that couch, get up from your desk, and just move more throughout the day. Explore more ranges of motion that your body is capable of doing. With general knowledge of anatomy, one should be able to safely progress to higher activity levels.

As far as studies go with OA, a sedentary lifestyle is detrimental and can hasten the degenerative process of OA. Strengthening the muscles around the joint is KEY to unloading the joint and reducing pain therefore increasing functional ability. Combine that with education of better biomechanics and you have a recipe for slowing the degenerative process of OA.

@ JoachimG, what is your history with your meniscus (which is cartilage) injury?

[JoachimG]

@ JoachimG, what is your history with your meniscus (which is cartilage) injury?

I feel in a football game, landed wrong, tore a part of the back of my lateral meniscus and had that part removed. I've been in chronic pain since the surgery a little over a year ago, but lately I started moving with bodyweight squats etc. and as long as I take it slow, it actually helps a lot.

Or do you mean more of my total body history? Cuz I was actually as you said, I went from sedentary to active. I went from 142 kg to 80 kg through hard work in about 18 months - and then in a friendly game the injury happened as I tackled a friend...

[Jim Pickles]

(Cregan thanks for your response. Maybe you'd like to look at this and see if it seems sensible to you. Yes, I do have access to paywalled literature, but I try not to refer to papers that other people can't access. Jim.)

These are my conclusions after reading about why the medial bearing surface of the knee is particularly vulnerable in knee osteoarthritis, and how we might help to protect our students. The information comes mainly from the paper by Reeves and Bowling I referred to above, but also from the Expert Consensus Guidelines that Cregan linked to.

The first part is a summary of the information from Reeves and Bowling, which seems to be the consensus view among medical professionals.

1. When we stand evenly on both feet, the body weight is shared evenly on both legs. The hip joint, the knee, and foot are ideally all vertically one above the other. Therefore there is no tendency for the knee to bow in or out and the medial and lateral bearing surfaces of the knee joint are weighted equally (Fig. 1).

(click for larger version - can anyone tell my how to paste at a larger size directly into the posting?)

2. During walking, the weight is taken by one leg or the other. Because the centre of gravity of the body is not over the hip joint that is taking the body weight, the body weight is directed diagonally down to the supporting foot (line B in Fig. 2). (Gravity obviously still acts vertically, and the non-vertical vector in line B is accompanied by a sideways vector line D, which causes the hips to sway to the opposite side.)

3. Line B in Fig. 2 goes medial to the supporting knee. Therefore not only is the medial side of the knee loaded more, but there is a force that will tend to make the knee bow outwards. If this happens the force on the medial cartilage will increase still further. The magnitude of the outward force can be calculated from the distance between the two lower dots in Fig. 2 (giving what is called the moment arm).

4. The outward force varies during the stride (Fig. 3; redrawn from Reeves and Bowling). It is usually greatest early in the stride (heel strike) and there is usually a second peak during the push-off from the balls of the foot.

5. What is the relation to pronation that Kit has emphasised? Line A in Fig, 2 shows what happens when the weight is taken on the inner side of the foot. The line of body weight goes still further away from the centre of the knee, and the moment arm has increased. Therefore the force on the medial cartilage has increased, and the tendency for the knees to bow out further has increased. Note however, that even without pronation (line B ), the line of force goes medial to the knee so some damage may occur.

6. Some interventions include using insoles under the lateral edge of the foot, so that the weight is taken on the outer edge of the foot. This reduces the moment arm (line C), but not to zero. On the other hand, any attempts to correct pronation by using the upper leg muscles (rather than the ankle) to throw the weight onto the outside of the foot will enhance the tendency of the knee to bow outwards, making the problem worse.

7. What other interventions have be used to protect the knee before damage is done? Barefoot walking, or using thin ground-sensitive shoes (Vibram 5 fingers?) seem to be beneficial, for reasons that are not clear. Thick-soled shoes may be counterproductive, perhaps because they reduce ground sensitivity. A toe-out gait tends to shift the knee joint axis, reducing the moment arm. Shortening the stride seems to be reduce the moment arm too.

8. There have been many different suggestions for muscle strengthening to counteract the tendency for excess pressure on the medial cartilage. The multiple suggestions probably reflect the fact that there is no ideal solution, as well as the different degrees of disability encountered. Obviously, any other errors in the feet and legs must be corrected as well, but what do we teach our students, to help protect them from knee osteoarthritis?

9. Logically, there are only two sets of muscles that are in a position to give substantial help. The hip adductors (inner thigh muscles; dotted line labelled add in Fig. 2) are in a position to counteract the bowing-out of the knee joint when weight is placed on the foot in walking. If they contract when weight is placed on a single leg, the knee joint becomes stable in relation to the hips in the sideways plane (however, the contraction should not include the gracilis, since it crosses the knee joint and will pull the lower leg the wrong way).

10. However, pressure from the upper leg will still have a tendency to bow out the leg at the knee joint (because the upper end of the lower leg can still be pushed outwards), producing greater force on the medial knee cartilage. This can be counteracted by the iliotibilal band (which crosses the knee joint), as tensioned by the tensor fasciae latae muscle (dotted line labelled tfl in Fig. 2).

11. I return to my suggestion that in standing, students should be trained to feel a ”line of strength” going down the leg from the femur to the foot, with the force applied as evenly as possible along the centre line of the knee and down to the foot, and with awareness of muscle activation. In addition, in walking, particular attention should be paid to the hip adductors with activation in proportion to the pressure on the foot, and also to the tensor fasciae latae. Any tendency for the knee to bow outwards should be detected and counteracted. This means that in walking, the leg muscles should NOT be used in the most relaxed way possible, but some activation should be maintained, particularly in the medial thigh muscles (and the lateral ones maybe to a lesser extent). It is likely that the sensations from barefoot walking, or walking with a very thin sole, helps reflexly activate the muscles further up in the kinematic chain, helping to protect the knee.

[Ciaran]

@Jim- I see your point about referencing free material.

Everything I mention here is purely from my studies. I am lacking the years of clinical experience necessary for a more objective analysis of OA, but the knowledge in theory should transfer over well to the majority of the population.

1. Correct. Poor strength with agonist/antagonist muscles and poor neuromuscular control lead to faulty joint mechanics, increasing joint loading.
   
2. This is one of the key points. Walking/Running is a 1-legged activity. It is necessary to assess the patient unilaterally. To oppose the shift in centre of gravity from central to more laterally, the hip abductors are vital to ‘proper’ function. There are moment arms throughout the whole lower chain. A compensatory strategy that is common to decrease loading of the osteoarthritic hips/knee is a lateral sway of the trunk (i.e. Trendellenburg’s sign - http://en.wikipedia....elenburg's_sign).
   
3. This is where the hip’s external rotator (ER) are important. Typically hip ER, internal rotators, hip abductors/flexors/extensors are weak with medial knee OA. A simple observation of the correction activation of the ER is shown in Kit’s video for pronation. While standing, lift your toes off the ground and notice how the whole leg externally rotates. The goal here is to retrain (strengthen/using the muscles dynamically), to decrease excessive medial loading of the knee.
   
4. The force you are alluding to here is called the vertical ground reaction force (VGRF). There are some excellent videos on youtube showing the VGRF and how it changes during a stride. Also Fig 1. Shows the different levels of muscle activation seen during walking.
   
   • Figure 1. Here is the link to the high-res image: http://i.imgur.com/wQHznjH.jpg
     
   • 
     

[*]The VGRF during gait is demonstrated in Fig 2 (http://i.imgur.com/oORtinZ.png). The initial peak is initial contact followed by the dip in VGRF (absorption of force e.g. fat pads, tendons, menisci etc). On a side note most injuries are associated with the initial two peaks as there is a higher frequency of loading occurring.

[*]What came first the chicken or the egg, it can be hard to say. Was it the desensitisation of your feet from a lifetime of wearing marshmallows on them or did it start further up the chain at the hip. My guess is the former. I think at this point its important to point out that a knee adduction moment is normal to some degree. However, excessive pronation will increase the moment and therefore increased loading of the medial knee as you’ve noted!

[*]My theory here is that insoles are a short-term fix. The better and longer-term fix is harder however, as it requires an invested effort from the individual to correct their pronation. What are you going to do when you’re not wearing your shoes ‘special marshmallow shoes’ with ‘increased heel lift’, and don’t have the benefit of the insoles. Insoles in my opinion are a passive solution that does properly stimulate the nervous system to create a lasting change.

[*]The benefit of minimalist shoes, which is in my opinion second fiddle to barefoot walking, is that it stimulates a response from the body to properly activate the chain to reduce the VGRFs. While a toe-out gait tends to reduce loading of the medial knee you may see conversely a loading of the lateral knee and continued stress of the medial meniscus due to the increased joint space and the relationship between the medial collateral ligament and the meniscus.

[*]While there is no ideal solution there is definitely a spectrum of solutions. This ranges from remaining sedentary to a complete overhaul of lifestyle (i.e. reduction in weight, beginning an active lifestyle etc). In-between, there are conservative options i.e. strengthening of the whole kinetic chain, or interventions e.g. a cane for hip OA. Ideally you want to specifically strengthen the knee extensors, hip abductors/ER while also focusing on strengthening the whole lower kinetic chain.

• Other therapeutic options include knee tractions to reduce pain, or for short-term relief giving them nice marshmallow shoes to reduce the VGRF.
  

[*]If anything, here you want the muscles crossing the knee joint to be activated to help stabilise the knee.

[*]It is important to remember here that the iliotibial band (ITB), is a passive structure and has shown to not have any significant changes in response to ITB stretches etc. As you mentioned, look further up the chain to the muscles connecting to the ITB. The tensor fascia latae and gluteus maximus both attach to the ITB and if they are tight or loose OR have poor activation will influence the ITB.

[*]Here is the hard part. Creating dynamic exercises which ensure proper biomechanics while not overanalysing and becoming obsessive about ‘perfect form’. Gary Ward has some very interesting ideas regarding this. Check him out here: http://ww.whatthefoot.co.uk/. I agree with your point about barefoot walking and its effect up the kinetic chain.

@JoachimG – You’re in a tough spot and it sucks, there’s no point in sugar-coating it unfortunately. However, you can still do SO much about your situation. My advice is to keep doing what is working for you and once you reach a plateau increase the intensity again. Lastly, maybe find an activity which you can do safely and ENJOY, a group activity. This can really help get rid of the depressive thoughts that come with injuries. Apologies if I am assuming things that aren’t there J. I am happy to talk to you more about what I know and how we can help eachother!

Edit: Sorry about the bad formatting, still figuring it out.

[Jim Pickles]

Cregan - many thanks again for your detailed reply. I'm away from home at the moment so not in a position to respond much, but I think in any case all the issues are addressed now.

My own particular interest at the moment is in exercises and cues for as-yet unaffected people (my class members) to ensure that they use proper biomechanics so they have the least chance of ever developing knee OA. Anyone with actual knee OA, I would suggest goes to a physiotherapist, as it is too important an issue to be dealt with by people like myself.

"Creating dynamic exercises which ensure proper biomechanics while not overanalysing and becoming obsessive about ‘perfect form’" - of course - the people I teach do not yet have knee OA (and most will never get it), and this is one element of the class among many others, so we want to introduce exercises that do not create fuss and that can naturally be incorporated into their daily patterns of movement, while ensuring good habits. I'll look at that website you referred to later.

Finally, how did you get the figures incorporated into the reply to show at the size you did? If I copy and paste them in directly into the window when typing, they show in the preview, but when in the final view, all I see is a lot of nonsense characters. On the other hand, if I use the upload image method, only a small thumbnail shows, and you have to click on it to see a full-size image, which you cant see at the same time as reading the text.

Thanks, Jim.

[Dexterrao]

Hi All,

 

Sorry i am new here and i do not find out a way to post a new discussion. 

The problem i have been facing is Pronation and associated bio mechanics. I am male, 26 yrs old and its only recently i realized i am pronating in excess. I have been following the anti-pronation routine and the results are already visible. 

But the problem is my knees were knocked (inwards due to pronation, not much but visible) for long time and since i have started these exercise, it is trying to come back to normal position and that hurts a lot. I could say the my right feet is almost normal while the left knee hurts a lot. 

Do you have any stretch that focuses specifically on knocked knee and associated muscle groups ? Thanks in advance.


Vittal Rao

[Jim Pickles]

Dexterrao - I'd say focus on strengthening all the leg muscles. But you need to say where the pain is. If it is around the knee joint, particularly at the sides, my guess is that it is coming from the ligaments that give the joint stability (but you need to say if that is the case). With strength and stability, everything else will adjust over time. Because the knee is intrinsically vulnerable, I'd be very cautious about doing much stretching around the knee in any sideways direction, if the strength and stability have not been achieved first.

 

You should also be aware that it is common for over-strong and short quads to pull the knee-cap sideways - in this case the pain will be felt more around the knee cap. This should be dealt with by quad stretching.

 

On the other hand, if the whole knee is moving away from an knock-knee (inwards) position and the pain is muscular, the stretch will be felt on the outside of the thigh, particularly higher in the thigh (tensor fasciae latae). In this case, stretching the outside of the thigh would be a good idea - but I suggest that this is less likely to be the case.

 

But this really needs someone more informed than me to respond.

Jim.