Anterior Knee Pain – Patellofemoral Pain (PFP)

PFP is a common knee presentation which is characterised by pain behind or around the kneecap.

It can commonly be referred to as anterior knee pain, “jumper’s knee” or “runner’s knee” and affects up to 23% of adults and 29% of adolescents in the general population (Collins et al. 2018). The pain mostly occurs during activities such as running, cycling, climbing stairs, squatting or sitting, when the knee is in a flexed position (Collins et.al 2018).

The patellofemoral joint (PFJ) consists of two bones, the patella (kneecap) and the femur (thigh bone) along with cartilage, ligaments and tendons. The patella is shaped like an upside-down triangle that sits in a specific groove just below the muscle bulk of the quadriceps. The primary function of the PFJ is to act as a mechanical pulley for the quadriceps as the knee bends and straightens (Louden 2016).

Why do I have pain?

PFP appears to be due to excessive/altered forces being placed on the patellofemoral joint. In normal joint mechanics, the force between the patella and the femur is evenly distributed on the surface of the femoral groove (Louden 2017).

In some PFP presentations, an imbalance between the muscles that surround the PFJ is thought to cause a biomechanical dysfunction (i.e. altered movement patterns). As a result, mal-alignment of the patella can occur which changes the force between the patella and the femur to a more concentrated area. This causes irritation on the underside of the patella, resulting in pain (Louden 2016). However, there may be other factors that also contribute to PFP including; shape of bone in femur and patella, size of patella bone, position of femur (due to strength and alignment at hip or position and alignment of feet), attachment point of patella tendon, just to name a few.

Are you experiencing any of these symptoms?

•  Pain at the front of the knee or underneath the kneecap
•  Pain during activities that involve repetitively bending the knee for example when walking up or down stairs, squatting or running
•  Pain related to an increase or a change in training levels, surfaces, footwear etc.
•  Pain following sitting down for a long period with the knee flexed
•  Clicking, grating or crackling sounds of the knee

If you answered yes, what should you do about it?

Firstly, you should seek the correct diagnoses from your physiotherapist, who will be great at diagnosing all the reasons for why you are getting this pain. Secondly, based on your presentation and your goals, your physiotherapist will devise a management plan that will be specific to your needs. The most recent evidence for the management of PFP is largely based around correct exercise prescription to address the muscle imbalance that may be contributing to your presentation (Collins et al. 2018; Can der Heijden et al. 2015). Other interventions that have been found to be of benefit are orthotics, taping and braces. Your physio can also guide you on when these other interventions may be appropriate.

Once your initial symptoms are resolved, your physiotherapist will give you advice for the long-term management of your presentation so that you can reduce the risk of injury reoccurrence.

Don’t let anterior knee pain be a burden on your health and limit your tolerance to exercise! With the correct management, you can be pain-free.

Published May 15, 2019