Runner’
s Knee also called Kneecap Maltracking or Patellofemoral pain syndrome (PFPS)…. which is the technical jargon term for the kneecap not sitting where it should be as you run. Now this is a very, very common problem. In fact, without looking at the stats on the patients I see at work I would estimate that 2-3/10 patients that walk through the door to see me complain of this problem and most, but not all are females.
So…what causes this problem? Runner’s knee is caused by what we call supraphysiological loads (or loads above what it can cope with). This occurs either through a single maximal load, or more commonly after repetitive overload. Now the exact cause of the pain in runner’s knee is still unclear, however a cascade of events eventuate that potentially leads to inflammation of the synovium (the joint outer lining) or potential bone stress. Now I want to stress that the articular cartilage, which is on the under surface of the kneecap can’t be the source of the pain as it does not have a nerve supply.
Unfortunately under more advanced situations or circumstances the undersurface cartilage on the knee can become fibrillated or worn leading to what we call chondromalacia patella (CMP) or potential arthritic changes can eventuate. These changes can be seen with a MRI scan. However a simple xray can highlight any arthritic changes in the knee. Sometimes a Sports doctor will organise for a CT scan on the knee to check the alignment of the kneecap in full detail without having to undergo any surgery. With the situations mentioned above, sometimes conservative treatment can manage the problem, however potential surgery is sometimes the end result. With advanced technology the use of stem cells or synvisc are also options. With more advanced conditions such as CMP or osteoarthritis of the patella it is critical to maintain the strength in the quadriceps and avoid compression on the under surface of the kneecap when possible. This is achieved by staying clear of squats, lunges and high steps if possible. There are many other ways to strengthen the quad muscles….
Ok… lets talk with terms that I have used before… Runner’s knee like many overuse injuries have intrinsic and extrinsic links to the problem. Primarily what we look for as potential links as Sports Physiotherapists or Podiatrists are contributions from the feet or hip which we call remote factors. Additionally local factors at the knee can contribute to the problem. I will expand on this! Extrinsic factors such as training frequency, volume and type of loading also play a critical role in influencing this problem.
Intrinsic Factors
Local Factors: From looking at the picture above you can see that there are numerous structures that insert into and around the patella or kneecap. Therefore anything that attaches to it can act as a pulley and influence the natural position of the kneecap. So one factor we look for as Sports Physio is patella mobility (how mobile the kneecap moves), as tightness in the outer structures of your knee that insert in the outer or lateral part of the kneecap (lateral retinaculum with contributions from the ITB and hamstrings) can cause concerns. Also the strength/timing of a muscle called your VMO (the inside muscle on your knee that is large on cyclists) is a key factor to look at.
Now the VMO is a critical muscle and if either its timing is not there (brain/muscle connection is poor) or the strength is down then the patella can have a tendency to move laterally or to the outer part of your knee. I like my patients to visualise this like a “tug of war”. Where the VMO is on the inside of the knee and the potentially tight outer structures that I mentioned above can potentially pull the kneecap to the outer margins of the knee during activity.
On the other extreme some patients with runner’s knee have a hypermobile (too much mobility) kneecap. Typically these patients lack the strength in their quadriceps and VMO to stabilise the kneecap. Also, these patients typically have factors around their hips linked in with the problem… which leads me to –
Remote Factors: These can be more complex to visualise. Potential links to the runner’s knee problem relate to the following:
- Increased femoral (thigh bone) internal rotation
- Increased knee valgus (or bending inwards)
- Increased tibial rotation (shin bone)
- Sub-optimal subtalar (joint below the ankle) pronation (Inside arch moves towards the ground)
- Inadequate flexibility (quads and hamstrings specifically)
Now… there are some technical terms there… so lets break it down! The top two are typically linked to a lack of control around the hip area. Primarily your glutes are not strong enough to support your lower limb and stay biomechanically sound. So there it is again… the glute!!! Such an important area to keep strong as a runner. Now the feet can also play a big role here… so this is for the podiatrists out there! Lack of control in the feet (possibly through poor runners or old runners) or over pronation have mechanical influences up the chain of the leg. That is due to the bony architecture or arrangement, pronation leads to internal rotation in the shin, knee and thigh bone which can also influence the kneecap’s position. This is why some podiatrists will prescribe orthotics for the problem. While flexibility or the lack of in key areas can pull on the kneecap as I described with the “tug of war” analogy.
So…. it is our job as Sports Physio’s to nut out with every single person that comes in to see me at the clinic… which of these factors are the major contributing factor(s) in their problem. That is everyone with runner’s knee is different. Some have local contributing factors, some have remote contributing factors… some have a combination.
Treatment options
Numerous studies have come out to show that Physiotherapy management of this problem is extremely effective. So if you have this problem, check in and see me at the clinic as normally through a few sessions the problem can be rectified.
Ok… If you were watching the Olympics…. which would be just about all of you! You would have seen this blue tape on the athletes and wondering, what the hell is that? This is rocktape or kinesio tape. I have been playing around with it over the last year and find that it is as good as traditional sports tape but the added benefit of being able to stick better and have more flexibility or give in its structure, thus allowing runners to put it on without really noticing that it is there. Pretty cool isn’t it. So this tape aims to reduce your pain thus typically allowing you to continue running or playing sport while you work on your specific contributing factors leading to runner’s knee. The more typical form of taping is the Mc Connell tape which aims to move the kneecap to the inside. Rather then mechanical provide assistance it helps by facilitating VMO activation and to provide feedback to the knee to reduce pain.
Physio helps with the following…. if your VMO is weak and not working well, I give you exercises to remedy it. If your Glutes are weak, then you will be given strengthening exercises to remedy that. If you are very tight on the outer structures of your knee, you may be sent home with a foam roller or have to do self myofascial release (self massage) to the tight areas. Also, if the feet are playing a role then a podiatrist may need to be involved with your care for advice on running shoes and potentially orthotics if there is a very clear contribution from the feet.
So…..before I write yet another thesis… I will wrap it up there! Happy weekend… please share this blog with anyone that you feel would benefit from it.
Please feel free to check out my website www.free2run.com.au and if you have any questions please feel free to shoot me an email!
Happy running!
Ross Kinsella
