Patellofemoral Pain Syndrome (Runner’s Knee): Your Complete Guide

By Jonathan S. Chu, M.D.
Interventional Pain Management
Physical Medicine and Rehabilitation

So you’re having persistent pain in the front of your knee, right beneath the kneecap.

 

It could be due to a condition known as “Runner’s Knee,” or as doctors refer to it, Patellofemoral Pain Syndrome (PFPS).

 

It is a very common condition that I personally see and treat often.

In fact, it’s estimated that almost 10% of visits to sports medicine clinics are due to PFPS.

 

Broadly speaking, PFPS is an “overuse and overload” injury.

This means that it’s the result of excess and repetitive stress on the knee, usually in the setting of malalignment and muscle imbalances of the thigh.

Anatomy:

First, to better understand this condition, let’s talk about the anatomy involved.

 

The key structure involved is your patella, more commonly known as your knee-cap. It’s located in the front of your knee.

 

The patella is a large bone located in the middle of the tendon of the quadriceps muscle (the large muscle in the front of the thigh).

 

With every step a person takes, the patella is designed to glide smoothly in a groove in the front of the femur (thigh bone).

 

The area where the patella meets the groove is known as the patellofemoral compartment.

 

There are a lot of factors that can cause mechanical problems of this joint, resulting in PFPS.

 

This lead to our next section…

What Causes Patellofemoral Pain Syndrome (PFPS)?

Repeated weight-bearing is the most common cause of PFPS, which is why this condition is often described as an “overuse” and “overload” injury.

 

Walking and running up hills, stairs, and along uneven surfaces place extra stress on the patellofemoral joint, and are hence notorious for causing and exacerbating patellofemoral pain.

 

Furthermore, having either flat feet (pes planus) or excessively high arches (pes cavus) is also thought to contribute PFPS.

 

In both cases, the abnormal foot shape can cause subtle changes in your gait, placing extra strain on the patellofemoral joint. This is why arch supports are commonly used to treat PFPS in patients with flat feet.

 

Also, weakness of the quadriceps muscle in the front of the thigh can cause abnormal tracking of the patella along the groove. Hence, this is another common factor that can contribute to the development of patellofemoral pain.

 

The VMO (Vastus Medius Obliquus) is the innermost muscle of the quadriceps. It is believed that weakness of this specific muscle causes the patella slide excessively outward during movement.

 

A tight iliotibial band (IT band) is another factor that can contribute to patellofemoral pain. Your IT band is a long thin strip of connective tissue that runs along the outside of your thigh. If it is too tight, it can pull the patella outwards every time you take a step. This results in abnormal tracking and excess stress on the patella.

 

Tight hamstrings and tight calf muscles can also contribute to PFPS by causing greater pressure between the patella and the femur.

Treatments:

 

Relative Rest:
In the early stages of recovery, it’s important to reduce activities that stress your knee.

 

This doesn’t necessarily mean that you need to refrain from exercise altogether—only reduce the activities that exacerbate your symptoms.

 

For example, if you’re a runner with PFPS, it would important to reduce running mileage during the initial period of your recovery. You could replace running with another form of exercise that places less stress over the patellofemoral system, such as swimming or a low-impact elliptical machine.

 

Furthermore, ice has anti-inflammatory effects and can be very helpful during acute flare-ups of PFPS. You can apply a bag of crushed ice or a frozen gel pack wrapped in a towel for 10-20 minutes at a time to help relieve acute symptoms of patellofemoral pain.

Knee Injection:

The patellofemoral compartment of the knee usually communicates with the main joint cavity of the knee (the medial and lateral compartments).

 

This means that the joint fluid of your knee flows continuously between the patellofemoral compartment and the rest of the knee joint.

 

This also means that medication injected into the knee joint will spread nicely into the patellofemoral compartment (or vice-versa).

 

If your pain is very severe and limiting you from participating well in your rehabilitation program, your doctor could perform a knee injection for you.

 

With this procedure, your physician will draw up a corticosteroid, which acts as a potent anti-inflammatory medication, and usually mix it with a numbing medication. After cleaning the knee thoroughly, your physician will inject the mixture into the knee joint.

Most physicians will only require bony landmarks to guide the injection. In some cases, image guidance with either ultrasound or X-ray (fluoroscopy) can also be used to increase the accuracy of the injection.

 

The goal of this injection is to quell the painful inflammation for a few months, allowing you to move better and improve your performance in physical therapy.

Bracing
Knee sleeves are very popular among patients with PFPS, though their use is still rather controversial among doctors.

 

These braces are designed to prevent the patella from sliding outwards during movement. They usually have a cut-out area for the patella and have a built-in buttress to help guide motion of the patella.

 

As of right now, the use of knee bracing for patellofemoral syndrome has not been studied enough to have strong scientific evidence to support their use.

 

However, anecdotally, many of my patients really like using them have reported great benefits from them.

 

Overall, I would say that bracing is potentially helpful and has few downsides if used properly. You’re welcome to try one to see if you notice relief. However, from a medical standpoint, it is not really considered a mainstay of treatment.

 

 

Shoes, Arch Supports and Orthotics
Switching to high-quality athletic footwear can often make a difference and improve patellofemoral pain. For runners, we recommend changing to a new pair of shoes after every 300 to 500 miles.

 

If you have flat feet (pes planus) and excessive inward rolling of the feet during walking, then using arch supports can often be helpful. Many patients get great results with soft over-the-counter options. Custom orthotics such as the UCBL are also an option, though at this point it isn’t clear from the medical literature whether they provide superior results compared to the over-the-counter options.

Surgery
Surgical treatment is one of the options available for patellofemoral pain, though it is definitely considered a treatment of last resort.

 

If the cartilage beneath the patella is significantly frayed (chondromalacia), then arthroscopic surgery to shave down and smooth out the cartilage is a potential option.

 

Also, if the patella is clearly tracking outwards during activities and this has not improved with stretching, taping, and bracing, then a lateral release surgery could be considered. This involves cutting the lateral retinaculum, an area of connective tissue that pulls the patella towards the outside.

 

In general though, it is very much important to emphasize that the vast majority of cases of PFPS get better with conservative treatments alone, such as physical therapy, and surgery is rarely necessary.

Thank you so much for reading. I absolutely commend you for taking the time and effort to educate yourself about your pain.
As a physician, I believe it is so crucial to take a proactive approach to your health. I know that your dedication will pay off over time.

Until Next Time,

Jonathan S. Chu, M.D.

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Dr. Jonathan S. Chu is a physician who specializes in Interventional Pain Management and Physical Medicine and Rehabilitation (PM&R), and is the founder of 360 Pain Academy.

Dr. Chu earned his medical degree from the Penn State College of Medicine / Milton S. Hershey Medical Center. Afterwards, he completed an internship in Internal Medicine at Lankenau Medical Center. Next, he pursued residency training in the field of PM&R at the Weill Cornell Medical Center and Columbia University Medical Center Combined Program. He went on to fulfill a fellowship in Interventional Pain Medicine at the University of California, San Diego Medical Center, where he learned advanced procedures for the treatment of pain from renowned leaders in the field.

He is double board certified in Physical Medicine and Rehabilitation and Pain Medicine.

References

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Halabchi F, Abolhasani M, Mirshahi M, Alizadeh Z. Patellofemoral pain in athletes: clinical perspectives. Open Access Journal of Sports Medicine. 2017 Oct 9;8:189-203.

Juhn MS. Patellofemoral Pain Syndrome: A Review and Guidelines for Treatment. American Family Physician. 1999 Nov; 60(7):2012-2018.

Waldman SD. Atlas of Pain Management Injection Techniques. St. Louis, Missouri. Elsevier 2017.

Waryaszand GR and McDermott AY. Patellofemoral pain syndrome (PFPS): a systematic review of anatomy and potential risk factors. Dynamic Medicine. 2008; 7: 9.

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