Runner's Knee: Patellofemoral Pain - Causes and Treatment Strategies.

Anterior Knee Pain in the Active Individual: Patellofemoral Pain

Anterior knee pain is a common complaint among that active population.  It can have many causes and can be from a few different causes.  The two most common in young, active individuals are patellofemoral pain, and patellar tendinopathy.  In this post, we will be talking about patellofemoral pain.

Patellofemoral pain:

• What is patellofemoral pain?

• Also referred to as "Runner's Knee"
• Your knee cap (patella) rests within a groove at the bottom of your femur.  This groove is referred to as your trochlea.  As our knee bends and straightens, our patella glides along this trochlea.  In our body, our quadriceps muscle becomes our quadriceps tendon who's fibers house the patella and continue below to form our patellar tendon which attaches onto our tibia (shin bone).  The patella serves to increase the mechanical advantage of our quadriceps allowing it to produce much more force than it would otherwise.  The contraction of our quadriceps creates compression of our patella against our femur.  This compression in and of itself is not bad.  Our bodies are strong and resilient and forces such as compression, shear, and torsion are happening all over our body all the time and do not produce pain.  However, the lower body of an athlete, runner, weightlifter etc. has to handle a lot of stress due to the high speeds, high weight, and high volume of work that their activity requires.  Sometimes the amount of stress we put through our joint is a little more than what we have prepared it for with our training and it results in pain.

• What causes patellofemoral pain?

• The cause of patellofemoral pain is overload of the joint articulation between the patella and the trochlea of the femur where the patella rests.
• There are a few things that we can do to make this less likely to happen:
• Avoid progressing your training too quickly:
• If you are a runner, it is wise to follow a structured running program designed by a professional to avoid overuse. A good general rule of thumb is to not increase your mileage by more than 10% / week.
• If you have never run before you can follow a simple "Couch to 5k" progression
• If you have a decent base and are looking to train for longer races it will be important to incorporate some strength training into your training program to alter the type of stress on your joints as well as improve running economy.  
• Address poor movement patterns:
• Take this point with caution.  It is impossible to move perfectly all of the time. 
• 2 potential contributing "movement faults" are "dynamic valgus" and "excessive anterior translation"
• Dynamic Valgus:
• Many people have heard of the term "valgus" or "dynamic valgus" which is a term to describe the knee diving inward during movements.  You may see people trying to completely train this motion out of every movement, and while their heart is in the right place it is often taken a little too far. 
• The reason that this "dynamic valgus" got such a bad name is because as the knee dives inward, the femur (which remember has the trochlea at the bottom that our patella sits on) turns inward into "internal rotation."  What that does is potentially create a little more rubbing, or "shear" force on the patella as well as creates less total surface area for force distribution.
• Imagine I take the tip of a pen, place it on your hand, then place a 20lb weight on the top of that pen.  It would really hurt.  Now instead of pen, I will put a piece of wood on your hand then put the same weight on top.  This would likely hurt far less, because though it is the same amount of force, it is spread over a much larger area. Dynamic valgus = potentially less surface area and potentially more likely for pain to develop.
• Excessive Anterior Translation:
• Most people who have been around athletics or the weight room know that what you squat, lunge, etc. you do not want your knee going past your toes.  This is not inherently a bad motion or else every person ever would have pain every time they go down stairs; but it will put some extra stress through the patellofemoral joint and does not allow the hamstrings and glutes to work as efficiently.  This makes that quadriceps much more dominant, and that quadriceps activity creates compression of the patella into the trochlea.  
• Once again, not an inherently bad motion, but it puts a little more stress through the joint so should not be our primary movement pattern.
• A caveat to this is that some people (maybe those with a shallow trochlea, i.e. less of a groove) may like the increased quadriceps activity because it makes that joint feel more secure, or just like above, helps to distribute the forces over a larger surface area of the patella and result in less pain.
• Avoid Overtraining
• It is very important to allow appropriate rest between intense days of training.  If you prefer to train 5, 6, even 7 times per week it is very important that you vary your training to allow for appropriate rest and recovery.
• If you are someone that likes to train 6-7 times per week, it may be wise to transition one or two of those days to an active recovery day, where your focus is more on low intensity, low impact cardio and stretching or yoga.
• If you play a sport, or even coach a sport, it may be beneficial to have some practiced days that focus on increasing sport specific athleticism and other days focused on skill work.  
• Not every practice needs to end with wind sprints and burpees.

• How is patellofemoral pain treated?

• There are many different ways that patellofemoral pain has been treated historically.
• Quad strengthening 
• Hip and Glute Strengthening
• Neuromuscular control training
• Taping / Bracing
• Orthotics
• Ice / Heat
• TENS
• All of these interventions have some potential benefits; but the common trend is that they allow the joint to rest.  If you decrease your workload, your pain will likely decrease (If it does not, then there are some other factors that may be at play, but that is a conversation for another day).
• Another common trend, is that pain will likely return if you make the mistake of doing too much too fast after your pain diminishes.
• Most injuries come from doing too much too fast after doing too little for too long
• This is where a good structured physical therapy program comes into play.  If you are a chronic sufferer of anterior knee pain, rest and gentle activity are normally enough to have it calm down, but as mentioned above, there are some biomechanical factors that can be addressed if present that makes your joint less likely to get overloaded.
• It is also important to slowly build up the tolerance of your patellofemoral joint to the stress that it will need to undergo during your activity, whether that be running, playing a field sport, Crossfit, going to the gym, or just walking up and down stairs.
• A good physical therapy program can guide the progression of your return to full activity to make sure that you do give your knee the best chance possible to remain pain free.

• I was told to strengthen my hips, why was that?

• The reason for strengthening the hips, is that our gluteal muscles are the most important at controlling that "dynamic valgus" that we have talked about as a contributor.  There is a lot of research that supports the use of hip strengthening to treat patellofemoral pain. The reason for this is that strengthening the hips and glutes does not create much compression through the joint like training the quadriceps will.  So.....that allows us to let the patellofemoral joint to rest (very important) as well as provide our hips and glutes with the appropriate strength that they will need to help control knee movement when beginning more strengthening with more "functional" movements like squats, lunges, etc. 
• Strengthening the glutes while lying on the ground with clamshells and leg raises does not translate into squatting and lunging with good control, but it provides the building blocks to make appropriate form easier to achieve.
• Once again, the common trend is that we are allowing the joint to rest initially followed by a gradual resumption of activities and compression to the joint.

• I have an important event coming up, is it safe to push through the pain?

• Yes!....well kind-of.
• It is ok to push through the pain, but the longer you push through the pain, the more likely it is that your pain will take longer to resolve, and the more likely the anatomical damage will be more significant (though that is not necessarily the determinant of pain, also a story for another day).  My recommendation would be to get in with a physical therapist that has a background in athletic training (ATC/LAT), or has a sports clinical specialist (SCS) certification as they will be able to make the best decisions around managing in season pain and may have some extra tricks up their sleeve with regards to taping techniques or bracing recommendations that may help you get through.
• It is also very important that you alter your training to allow the joint rest whenever possible.  A good physical therapist will also be able to help you with that.

• How do I know if my running form is causing the pain?

• Whether it is your form, or the volume of your training, it would be good to have someone trained in running analysis assess your running gait.  This will allow for some instruction on potential slight modifications to decrease patellofemoral stress.  
• Changing running form is not easy and this is not something that I would recommend while training for a race.  It should be an "off season"undertaking and unless you are a highly competitive runner, some small changes and getting onto a strengthening program will likely be sufficient to put your knee in a much better chance for success. 
• Training volume errors are far more often the cause than running form.  Make sure that you are following a reasonable progression, ideally one laid out by a qualified professional, but sticking to the 10% rule is a decent place to start.

• This sounds like what I have, what should I do right now?
• Your best bet is to get into a physical therapist to get set up on a program that is going to best help you. 

Hopefully this information was helpful.  For more information about me, or to request a free telehealth consult, visit reevespt.com