Have you noticed pain in the front of your knee? If so, you're not alone. Kneecap pain is a common complaint and can occur regardless of your age or activity level. When the source of pain is your kneecap it's referred to as Patellofemoral Pain Syndrome (PFPS) or more commonly as Runner’s Knee.
Pain from Runner's knee
PFPS pain is felt at the front of the knee or around the kneecap (patella). PFPS related knee pain occurs during activities that load the knee such as running, squatting, going up and down the stairs and kneeling. It can also be felt it n positions where your knee is bent for long periods of time.
Anatomy of your patellofemoral joint
Your patellofemoral joint consists of the patella (kneecap) and your femur (thigh bone). The patella sits in the groove of the femur (trochlear groove) . As your knee bends and straightens, several forces act on the patella to keep it moving, or tracking, in the groove properly. Your patella is embedded in the quadriceps tendon, which is where your front thigh muscle attaches into your shin bone (tibia). Additionally, your iliotibial band (IT band) has attachments to the outer part of your knee cap.
Kneecap movement
Your kneecap moves relatively as you bend and straighten your knee. Normal tracking with knee bending includes your patella sliding down and also includes tilts and rotations. As it does this and there are various points of contact between the patella and the femur. When your quadriceps muscle contracts during knee extension, the tendon pulls the patella upwards and slightly laterally (to the outside). The iliotibial band has some attachments to the outside of the patella and also contributes to the lateral tracking of your patella.
The exact tracking of your patella in the groove is influenced by the forces of the quadriceps muscle, the iliotibial band, and the patellofemoral ligaments.
Contributing Factors to PFPS:
There are several factors that can contribute to PFPS. These include:
Weakness of your quadriceps muscles
Weakness in your quadriceps can alter the alignment and tracking of the patella and provoke PFPS. This can influence your patellar tracking and the load distribution on your knee joint.
Weakness of your gluteal (butt) muscles
How can a muscle that doesn't attach into your kneecap influence pain so far away? Your gluteal muscles don't directly pull on your kneecap but they control the rotation of your hip. Weakness of this muscle group can cause your leg to dynamically rotate in. This can result in a stronger outward force on your kneecap.
Patellar orientation
In some cases, the patella has an anatomical malalignment which may cause it to glide more to one side of the trochlear groove on the femur. This in turn may cause overpressure on that part of the femur leading to pain and irritation.
Over training
A rapid increase in frequency and/or magnitude of patellofemoral joint loading at a rate that surpasses the ability of the tissues to recover can lead to pain. This is commonly seen in runners that increase the frequency or distance of their runs too quickly.
Muscle Tightness
Reduced length of quadriceps, iliotibial band, or hamstrings can increase the compressive forces at your patellofemoral joint and affect patellar tracking.
What Can be done to treat PFPS?
If you're currently experiencing pain from PFPS the first goal should be to reduce your pain. Our previous articles have discussed whether to use heat or ice for an injury and which brace to use for knee pain. Once pain is being addressed, the next step in trying to self manage PFPS is to address the common areas at fault.
Getting started on releasing tight hip muscles
One of the ways to release tight hip and knee muscles is through foam rolling. Foam rolling the quadriceps, iliotibial band, and hamstrings can assist with improving the tracking of your patella.
Getting started on hip strengthening
An initial exercise to begin strengthening your gluteal muscles is the side lying hip abduction exercise. To do this exercise, begin in side lying (a band around your knees is optional). Your knees should be straight and your legs should be slightly behind your body (slight extension). Lift the top leg to abduct the hip. Do not move your leg forward as you lift and do not rotate your foot up. Lower and repeat. Our previous blog post showed a quick technique to check if you have weak hip muscles. Click here to see how to test yourself.
Should I see a physiotherapist?
Research has shown that a physiotherapy program involving strengthening, advice on gait and running biomechanics, and symptom management strategies can help reduce pain and increase function in individuals with PFPS. The physiotherapy assessment will entail examining the alignment and movement of your hip, knee, and foot, the strength and flexibility of lower extremity muscles, and a gait analysis. If you're a runner, a running assessment should be performed as your pain allows to identify factors contributing to your pain. As you improve, exercises should be progressed to functional retraining exercises.
In order to diagnose PFPS, all other possible knee injuries should be excluded. These include topics of our previous articles on meniscal tears, ligament injuries and pain referred from your low back or hip.
A physiotherapist can help you select and progress your exercises based on your assessment findings to reach your activity goals.
References
Crossley, Kay M, et al. “2016 Patellofemoral Pain Consensus Statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: Terminology, Definitions, Clinical Examination, Natural History, Patellofemoral Osteoarthritis and Patient-Reported Outcome Measures.” British Journal of Sports Medicine, vol. 50, no. 14, 2016, pp. 839–843.,
Esculier, Jean-Francois, et al. “The Effects of a Multimodal Rehabilitation Program on Symptoms and Ground-Reaction Forces in Runners with Patellofemoral Pain Syndrome.” Journal of Sport Rehabilitation, vol. 25, no. 1, 2016, pp. 23–30.,
Willy, Richard W., et al. “Patellofemoral Pain.” Journal of Orthopaedic & Sports Physical Therapy, vol. 49, no. 9, 2019, https://doi.org/10.2519/jospt.2019.0302.
