Runners Knee – AKA patella-femoral pain syndrome (PFPS) Pain on or around the knee cap (part 2)
In part 1 of this blog (HERE) we discussed what runners knee is, in part 2 we will look at how I treat it. Firstly, management would always begin with patient education (always), this goes for every condition I see. I believe, it’s extremely important that the patient knows exactly what’s going on, why it’s happening, what we are going to do to get it better and to answer any questions or address any fears they have. I can’t emphasise this strongly enough. In addition to this I will use my gait re-education expertise and often strengthening/mobility exercises to address the issues that have been identified in the assessment. The gait re-education cues I use, will always be guided by what I see on the treadmill, and this is often very individual and differs from person to person. However, for the purposes of this blog I will take you through the common characteristics I see in clinic.
The dreaded overstride . When you overstride, your foot lands way ahead of your centre of mass (COM). This increases the load at the patella femoral joint (PFJ) as the quads go in to overdrive (when your quads are working, they have the effect of pushing your patella into the groove on the femur and thus increases the pressure on the PFJ). Remember that running is a repetitive activity, so you will get the same loading patterns around the PFJ on every step. This accumulation of stress is what causes the issues. In human locomotion the quads (along with other muscles) have 3 major jobs: 1) As your foot hits the ground, overcome gravity to prevent your skeleton from falling to the ground 2) pull your mass (everything above the hips) over your base of support (your foot) 3) Propel you forward for the next step. With every overstride you’re making your quads work very hard in those first 2 phases. The closer you land to your COM, the less work the quads have to do to a) prevent you from collapsing to the floor, because your skeleton will do more of that work (because you are positioning your base of support under your COM) and b) less work to pull your mass over your base of support, because it’s right there! Not as far to go. Net result = less stress over the PFJ.
Low cadence (how many steps you take in a minute). Usually goes hand in hand with an overstride. If you have a low cadence, like many recreational runners, they compensate by trying to gain more speed by increasing their stride (speed = cadence x stride length), which leads to the exact issues above. It also tends to increase the degree of knee flexion, which also places more stress over the PFJ. You can test this yourself by jumping up and down on the spot quickly at around 180 bpm and then jumping up and down at 120 bpm. See how much more your knee bends at 120bpm
Poor hip control. This is another common one. If we think back to the analogy of the patella being the train on the tracks (see part 1) (overly simplistic I know!). If the train is moved more over the lateral track, it will cause increased pressure on the lateral facet (the outside part of the patella), and increased “stretch” or “pinch” on the medial patella soft tissues. If the tracks (femur) move from under the train (patella), let’s say by medial rotation of the femur, the same thing occurs, i.e. more compression over the lateral patella facet and more “stretch” or “pinch” over the medial soft tissues. The usual control issue at the hip is medial rotation and adduction of the femur (valgus knee) during the stance phase (see fig 1 & 2). The medial rotation and adduction of the femur will cause the tracks to move on the train, as outlined above.
Turned out feet. This gait feature can lead to an increase in medial rotation at the tibia (shin bone), and therefore increased medial rotation at the femur, again, leading to the above changes. Turning the foot out when running, is usually a subconscious “choice” and is often due to trying to increase lateral stability (by increasing your base of support) or due to a restriction in dorsiflexion or great toe extension.
- Anterior pelvic tilt or bending forwards from the waist. This has the effect of shifting our centre of mass forwards during stance. This will have to be compensated for in the next stride to prevent your trunk toppling forwards. To achieve this you will have to overstride = more load on the knee (see above)
So once we have worked out what the issues could be, we need some tricks to modify them and take the load off the PFJ.
How to change running features 1) and 2)
One of the easiest ways to change both an overstride and low cadence, is to run to a metronome set about 5%-10% more than your current cadence. Remember, you don’t need to be perfect, you just need to be better than you are at the moment. Another cue I use, is to gain a slight increase in heel lift after toe off. The imagery I use is borrowed from my chats with James Dunne at kinetic revolution:
“Imagine you’re running through tall grass” or “imagine you are running through shallow water and you just want to lift your heel enough to clear the water/grass” another good one is “imagine you have a hurdle on the inside of both ankles and you want to clear the hurdle with every step”. This slight heel lift helps attain a more desirable swing phase, leading to the foot being placed down closer to the COM and under a vertical tibia, rather than flicking out in front of the knee in a big overstride.There are lots of free metronome apps out there to help with increasing cadence.
How to change running feature 3)
To help cue an increase in hip activity, to improve the hip control element, I aim for a slightly wider step width with toes forward. “Imagine landing directly under hips” or “Imagine running either side of a yellow parking line.
Video from the gait guys working on increasing step width. The first part of the run the athlete runs normally (and displays cross-over gait) the second part of the video the athlete runs either side of the drain to increase step width.
How to change running feature 4)
Toes forward – simple – toes forward.
How to change running feature 5)
Instruct your runners to run up tall. You can also use cues such as ‘hips high’ or get them to imagine they have a helium balloon tied to the crown of their head and is gently pulling them up.
If the above cues are going to work for you, you should feel a real difference in pain immediately, or within 30s to 1min of changing the cue. If your pain does not change, then this cue is not working for you. Never run through pain and always consult a good physiotherapist, ideally one that specialises in running injures, if your pain is persisting.
Here’s a couple of bonus exercises I often use alongside the above cues to activate the right muscles.
Single leg squats – James Dunne from kinetic revolution does a great job in explaining the ideal technique for a single leg squat
The gait guys – Talking about the “cross-over gait”. Go to 2min 18secs for the “penguin walk” exercise
These are just my thoughts and opinions on a very common running injury based on my knowledge of the literature and what I see in practice. I hope you find it helpful and if you have any comments, please feel free to get in touch.
Taunton J. E., Ryan M. B., Clement, D.B., McKenzie, D.C., Lloyd-Smith, D.R., Zumbo, B.D. (2002) A retrospective case-control analysis of 2002 running injuries. British Journal of Sports Medicine, 36, 95-101.