What You Need to Know about Patellofemoral Pain Syndrome (Runner’s Knee)

In the running community, patellofemoral pain syndrome (“PFPS”), or Runner’s Knee, has a reputation for being painful and frustrating. Despite its nickname, Runner’s Knee can affect people who have never run a single step.

Signs & Symptoms

Typically patients affected by PFPS will feel vague, diffuse unilateral or bilateral pain throughout the front of the knee that can feel like aching pain or sharp pain.  

It can be easier to understand if you know that the patella, or knee cap and femur, or upper leg bone, are connected -- so PFPS is essentially pain caused by the joint where the knee cap and upper leg bone meet. 

PFPS pain can become worse during running, jumping and ascending and descending stairs.  It can also increase with prolonged sitting and inactivity.  One of the common symptoms is referred to as “Movie Theater Sign”, which is pain in the front of the knee when standing after a prolonged period of sitting with your knees bent.

Runner’s Knee symptoms are usually vague because there is not a specific mechanism of injury, and pain can develop for many different reasons.  The athlete will typically not remember when the injury occurred, and the symptoms will gradually worsen with time if nothing is done about it.  

Runners might initially notice the pain after a run, and as time passes will start to have pain during running, and ultimately will reach a point where they can no longer run due to pain. 

For people who aren’t runners, going up and down the stairs, sitting, walking and other activities that involve flexing the knee may feel painful.

Causes

The cause of PFPS pain can be multifactorial, coming from a number of places.  It can occur for these reasons, among others:

• Natural posture: patellar position, knee position (being knock-kneed);
• Weakness in your core, gluteus or thigh muscles;
• Tightness in the hip, thigh or calf;
• Improper training;
• Starting a physical activity without proper warm-up;
• Increasing distance or frequency too quickly when training for a race;
• Lack of cross training;
• Improper footwear, including wearing the wrong style running shoe for your body or not changing out your shoe wear often enough. The average running shoe will safely last 300-500 miles. 

Treatment

The best option for PFPS treatment is to seek evaluation from a Sports Medicine provider or physical therapist as soon as you experience symptoms.  

Resting or avoiding the activity causing your symptoms is one way to get rid of Patellofemoral Pain Syndrome, but others that your medical provider can help with may include: 

• Adding correct strengthening exercises tailored to you, for glutes, quads and core muscles;
• Changing your training techniques.  Runners typically shouldn’t increase distance more than 10-15% per week, or less for new runners.
• Shoe wear.  Your physical therapist can offer shoe advice as well as direct you to knowledgeable running-specific shoe stores in your area.
• Bracing or taping techniques that may be helpful.    
• Incorporating correct stretching for the hip flexors, hamstrings, IT Band and calf muscles
• Adding cross-training to your routine. If you are only running, sometimes it can be helpful to add another activity to the mix, like cycling, swimming, Zumba, yoga and Pilates.

Just remember, if the activity is painful, you're better off not doing it.

Matthew Erbe DPT, ATC, is a senior Physical Therapist with OrthoCarolina Sports Medicine 

This article was originally published on January 26, 2015, and has been updated on January 8, 2021.