Runner’s knee – Between a rock and a hard place

Runner’s knee, or more technically iliotibial band friction syndrome (ITBFS), is a potentially debilitating condition causing pain at the outside of the knee.

It is a non-traumatic overuse injury caused by excessive friction in the area between the iliotibial band (ITB; a thick fibrous band which acts to reinforce the hip and knee musculature) and a boney prominence located on the lateral knee. Or, as I like to think of it, the “territory” caught between a rock and a hard place. The rock being the bone and the hard place being the ITB.

But what causes this territory to become sore? As we walk or run, the knee cycles between flexion and extension. At about 30⁰ of knee flexion the territory caught between the rock and a hard place gets squeezed. This squeezing of the structures happens to everybody, but why doesn’t everybody get sore?

Studies have shown that people with certain biomechanical deficiencies (i.e. increased amounts of hip adduction and internal rotation, see picture) are more vulnerable to this territory impingement and more likely to develop runner’s knee.  When running, the extra movement from such deficiencies leads to the knee not remaining straight over the toes but rather coming in towards the other knee (knock knees). Going back to our analogy, this abnormal movement means that our hard place (ITB) is now at a greater length, and hence will impinge on the rock (bone) with even greater force.

The increased force of impingement can lead to several potential pathologies around the lateral knee which end up causing the pain:

  • inflammation of a small flap of knee joint capsule (lateral synovial recess)
  • irritation of the posterior fibres of the ITB
  • inflammation of the outside coating of the bone (periosteum).

Once these problems start we usually don’t give the irritated structures enough time to settle and repair. A vicious cycle of further irritation and damage then begins. The area of impingement enlarges because these irritated/inflamed structures become slightly bigger therefore extending the possible area for impingement. And this cycle will go on and on if you allow it.

OK, so how did I get myself into this position in the first place?

The exaggerated knee movement is most often caused by a lack of control of the hip joint. Weakness of the gluteal muscles will mean the knee moves inwards to reduce the work of gluteal muscles and hence keep the pelvis more level.

Not often, but something that an experienced Sports Physiotherapist will look for as another potential cause is a stiff ankle. Stiffness in one ankle usually comes from an old ankle sprain which was not rehabilitated properly. An ankle that is stiff will not allow the knee to come forwards in a straight manner. Instead of compensating for this stiffness with very small steps, the knee moves inwards (extra knee adduction) to allow for a little more clearance of the ankle and longer (more normal) steps. If you think you have a stiff ankle causing this, a Sports Physiotherapist is perfectly suited to manage that for you.

But I have perfect ankles, great biomechanics and buns of steel!?!

Almost certainly in the case of not having these biomechanical shortcomings, the beginning of your ITBFS came from an increase in running load that your body was not capable of handling. Yes, your territory between a rock and a hard place undergoes less impingement than your biomechanically inferior running comrades, but the sharp increase in the number of steps you have taken has led to the same overall force applied to the territory in question.

Ok, so you now you hopefully have a good idea why you might have developed ITBFS. What are we going to do about it?

You will need to relatively rest. This is a term us physio’s use to mean rest from the activities that you know cause your pain. In most of your cases, this will mean running. It doesn’t always mean stop running completely! Perhaps your pain only comes on at the 5km mark. In this case, I would advise you only run 4km for a period of time to allow the damaged tissue a chance for repair. However, if you get sore in the first few 100 metres, then you will need to stop running for a period of time.

Effective use of your rest period would involve strengthening your gluteal muscles. Even simple exercises like side lying leg lifts and bridges will start the process of improving your biomechanics. This eventually results in more breathing space for your territory between the rock and a hard place, less opportunity for impingement, and lastly less likelihood of ITBFS.

Once you are strong and your damage has had the chance to repair the next questions is what type of running to begin with? If you think about how many times your territory in question goes through impingement, it makes logical sense that the less impingements, the less chance to develop soreness. This means that long slow plods are out the window. While you are in your recovery phase, higher intensity running done at a lower volume is best. An example of this is doing some 200’s. Doing something like 200’s will still allow for a nice blow and release of those sweet, sweet endorphins, but will also be kinder to your territory.

Hopefully a further understanding of the reason people get ITBFS in the first place and how to begin treating it will start you on your path to recovery. Contact an experienced Sports Physiotherapist such as myself if you need some help along the way!

Darren McMillan

Darren McMillan is an experienced AFL Sports Physiotherapist for the Richmond Football Club and also provides consultations in Melbourne (Brighton East) at “aPhysio” including both evening/weekends sessions. Visit www.aphysio.com.au for more information and online bookings.

References:

Ellis, R., Hing, W., & Reid, D. (2007). Iliotibial band friction syndrome—A systematic review. Manual Therapy, 12(3), 200-208. http://dx.doi.org/10.1016/j.math.2006.08.004

Louw, M., & Deary, C. (2014). The biomechanical variables involved in the aetiology of iliotibial band syndrome in distance runners – A systematic review of the literature. Physical Therapy In Sport, 15(1), 64-75. http://dx.doi.org/10.1016/j.ptsp.2013.07.002