The Knee and Macerating Menisci

Take a good look at the above 2 slides.

Notice that, during pronation, there is a medial rotation of the lower leg and thigh. We remember that, during pronation, the talus plantar flexes, adducts, and everts. This anterior translation and medial rotation of the talus causes the tibia and subsequently the femur to follow. This, if everything is working right, results in medial rotation of the knee.

From the slides, it should also be evident that the medial condyle of the femur and a medial tibial plateau are larger than the lateral. This allows for an increased amount of internal and external rotation of the knee. We remember that the meniscus, like a washer, is between the tibia and femur. We if you think about this kinematically, it would make sense that the tibia, during pronation (which occurs from initial contact to mid stance) would have to rotate faster than the femur otherwise the meniscus would be caught "in between". If there is a mismatch in timing, the meniscus is "caught in the middle", which causes undue stress and can cause fraying, degeneration, etc.

Likewise, during supination (from mid stance to pre swing) the femur must externally rotate faster then the tibia, otherwise we see this same "mismatch". This is a scenario we commonly see in folks who over pronate at the mid foot and remain in pronation for too omg a period of time. 

We think of pronation as being initiated from the movement described above by the talus, and it is attenuated by the popliteus muscle as well as some of the deep flexors of the foot, which fire mostly during stance phase. You will notice that the popliteus  is eccentrically contracting at this point.

Supination, initiated by swing phase of the opposite leg and momentum, is assisted by concentric contraction of the popliteus muscle, internal rotation of the pelvis on the stance phase leg, contraction of the vastus medialis, deep flexors of the foot and peroneii.

Taking moment to "wrap your head around" this concept. Now you can see how complicated it can be when we started to throw in femoral and tibial torsions as well as possibly some orthotic therapy. For example, in an individual with internal tibial torsion, if you do not valgus post the forefoot of the orthotic, the knee is placed at outside the sagittal plane in external rotation further by the orthotic and this thwarts the function of his mechanism, leaving the meniscus holding the bag. 

Know your anatomy and know what is supposed to be firing when, your patients and clients knees depend on it!

Change the foot, change the knee (and vice versa). A video case of External Tibial Torsion.

Here is a perfect example of external tibial torsion. Are you treating and training people and messing with their orthotics, squat knee-foot posturing or making gait/running/jumping changes or recommendations? If you are doing all of this and you do not know about tibial torsions, then shame on you, go apologize to these people right now. You could be causing them mechanical grief. Go buy them ice cream (even if they are “paleo”), that fixes most unintentional human mistakes. 

This is a classic presentation of external tibial torsion. This is an anatomic problem, you cannot fix this intrinsically, but you can help extrinsically. You teach these people about this issue and why the foot and the knee cannot cooperate. You teach them why their feet are spun out (increased foot progression angle) while their knee tracks straight forward sagittally. You teach them why they might heel strike far laterally and why their pronation phase might be abrupt. As in this video, you teach them why they might fashionably choose to narrow the foot progression angle (foot turned in) while at the same time having to bear weight on the lateral foot (in supination to externally spin the tibia) to keep the knee tracking sagittally. You teach them why this will be impossible to do in pumps (inversion sprain ouch) and why over time this will anger many joints and tendons. You teach them that without this accommodation they will track the knee inside the sagittal plane (as seen in the video).  You teach them why they might be at greater risk of having foot prontation issue pathologies, why they might have limited internal hip rotation, why orthotics likely do not do much for them (yes, there are exceptions), why certain shoes are a challenge for them while others are magical and why over time their once beautiful arch has begun to “fall” and be less prominent as they attenuate the plantar tissues.  

As you get good with this gait and biomechanics stuff, you should readily see and understand all of the issues discussed here today in a mere flash of instant brilliance so you know what to offer your client, in understanding and remedy options. As you have seen in this video, when left to their own devices, they naturally allow the knee to find the sagittal plane in a nice forward hinge. In this posture the foot is excessively progressed outward. Again, this is because of the tibial long bone torsion. This is their anatomy, this is not functional in this case. You cannot fix this, you help them manage this, first with their awareness, then with your brilliance.  You may implement exercises and gait strategies to help them become aware of mechanical issues and how to protect the foot-ankle, the knee and the hip. You teach them why they might have a tendency towards anterior pelvis posturing or sway back type postures. You teach them why, in some cases, they choose knee hyperextension as a comfortable yet lazy stance postural habit. You teach them why some shoes are “happy” shoes for them, and why others are pure evil.

A foundational principle we teach here at The Gait Guys is that the knee is a simple hinge between two multiaxial joints on either side of the knee, the hip and the foot-ankle complex. The knee really can only flex and extend, and when the mechanics above and below are challenged the knee has little depth to its abilities to tolerate much of anything except simple sagittal hinging. You can see that the foot posturing and tibial torsion rule the roost here in this video. You should learn in time that managing this case above and below the knee is where the pot of gold is found. You will learn in time that taping the knee is often futile, yet a worthy experiment both for you and the client in the discovery process, but that a life time of taping is not logical. External tibial torsion, although affording the knee that sagittal hinge plane, can narrow its range of safe sagittal mechanics and it is up to you to  help them learn and discover that razor’s edge safely and effectively when the torsion is large.  You should also discuss with them that as they plastically tissue adapt over the years (ie. pronate more and lose more arch integrity), this razor’s edge may widen or narrow for the knee mechanics as well as the hip and foot-ankle complex.  

For your reading pleasure, a classic example of how to interrogate a safe sagittal knee progression was discussed in this blog video piece we wrote recently, linked here.

Look and you shall find, but only if you know what you are looking for.

* Please now know that you should never off the cuff tell someone to turn inwards their outwardly spun foot. But if you do, have ice cream on hand, just in case.

Need more to spin your head ? Think about whether their IT band complex is going to be functioning normally.  Oy, where is that ice cream !

Shawn Allen, one of the gait guys

How do you know if your orthotic is working?

Foot orthotics are easy, no? You get casted, it gets built, you put it in your shoe and you’re good to go, right? Wrong!

Orthotics or Orthotic Therapy as we like to call it in our offices, is an ongoing process. If an orthotic is doing it’s job, your foot should change (for the better) and your prescription should become less. At least in an ideal world.

Remember, orthotics are designed to help you adapt to your environment better. Unlike a footbed (which merely creates a level playing field for the foot), they change the biomechanical function of your foot. A lot should go into getting fit for an orthotic, otherwise they can actually cause some of the problems they are purported to fix!

First of all, there should be a comprehensive history of you and whatever is going on, with an inventory of all your past injuries. That appendectomy or laporoscopy which invaded the abdominal wall could be a culprit for future problems. Next you should have a thorough examination of your lower kinetic chain, including the feet, ankles, knees, hips and low back. This should include range of motion, muscle strength, muscle recruitment patterns and joint function, along with reflexes, sensation and balance or proprioception. Next there should be an analysis of your gait, preferably with stop motion video which allows you to slow down movements and assess subtle abnormalities that may not be visible during normal speeds of movement.

At this point, it should be obvious to both you and your orthotic provider whether or not an orthotic is needed. If so, a non weight bearing cast (weight bearing casts show you what the problem or compensation is, why would you want to cast someone in their pathology and perpetuate it?) The non  weight bearing cast is usually done in a mid to terminal stance position of the foot. This should be followed by the prescription of appropriate stretches and exercises, specific to your condition. Shoe recommendations should also be given, since different foot types require different footwear characteristics (good news for the ladies who like shoes!).

So, if you need an orthotic (remember, the prescription should become less over time AND should be accompanied by appropriate exercises), these are the steps we feel are imperative, otherwise, you may just have a really expensive doorstop….

The Gait Guys….Promoting Gait Literacy, one stride length at a time.

How do I know if my orthotic is working?

Foot orthotics are easy, no? You get casted, it gets built, you put it in your shoe and you’re good to go, right? Wrong!

Orthotics or “Orthotic Therapy” as we call it is an ongoing process. If an orthotic is doing it’s job, your foot should change (for the better) and your prescription should become less. and less….Until you no longer need them… At least in an ideal world.

Remember, orthotics are designed to help you adapt to your environment better. Unlike a footbed, they should change the biomechanical function of your foot. A lot should go into getting fit for an orthotic, otherwise they can actually cause some of the problems they are purported to fix!

First of all, there should be a history of you and whatever is going on, with an inventory of all your past injuries. Sometimes there is a pattern that can be recognized and gives your provider clues as to what may be going on with you.

Next you should have a thorough examination of your lower kinetic chain, including the feet, ankles, knees, hips and low back. This should include range of motion, muscle strength, muscle recruitment patterns and joint function, along with reflexes, sensation and balance or proprioception. This gives us a benchmark and defines weaknesses and strengths.

Now there should be an analysis of your gait, preferably with stop motion video which allows us to slow down movements and assess subtle abnormalities that may not be visible during normal speeds of movement. If you are there for cycling orthotics, then a video of your stroke pattern is made. Sometimes, footage of your skiing technique can be helpful as well.

At this point, it should be obvious to both you and your orthotic provider whether or not an orthotic is needed. If so, a non weight bearing cast in terminal stance phase (This is a specific position of your ankle and foot) should be performed. This is usually followed by the prescription of appropriate stretches and exercises, specific to your condition. Shoe recommendations should also be given, since different foot types require different footwear characteristics. This will be good news for the ladies who like many shoes. Most guys just want the pain to stop and won’t care what they look like, as long as they are not pink!

Now you have an idea of what goes into (or should go into) building the perfect orthotic for you. Ask lots of questions of whoever is building them for you and make sure they are answered to your satisfaction. They should be a stepping stone to your recovery and  not a crutch for you to depend on. 

Telling it like it is, we are… The Gait Guys