- Patellofemoral pain syndrome refers to pain in front of the knee, under the kneecap. It usually occurs due to overuse rather than from a specific injury.
- Females and those with weakness in their quadriceps muscles are more susceptible to PFPS.
- Exercise that targets quadriceps strengthening is effective in reducing one’s risk of developing PFPS. Examples of such exercises are forward lunges, squats and step-ups.
Pain in the front of my knee. Where is it coming from?!
Anterior knee pain refers to pain felt at the front of the knee. Patellofemoral pain syndrome (PFPS) is one of the conditions that can cause anterior knee pain, more specifically pain under the patella (also known as the kneecap). It is the most commonly diagnosed condition in people younger than 50 years old with knee pain.
A specific injury or traumatic event rarely causes PFPS. The pain experienced usually occurs over time, often due to a sudden increase in physical activity resulting in overuse.
People with PFPS may describe the pain as a nagging ache or an occasional sharp pain. This pain may hinder walking, resulting in limping and activity limitations. In addition, pain associated with PFPS is typically most pronounced when going up and down stairs, squatting, running, or after sitting for a long time. Due to its relation to running, PFPS is sometimes also known as “runner’s knee”.
Will I get pain in the front of my knee?
Many factors contribute to a person’s likelihood of developing PFPS.
Firstly, the female sex is a risk factor for PFPS development.
Next, quadriceps muscle weakness is a significant contributor to an increased risk of developing PFPS. The quadriceps is a group of muscles located in the front of the thighs. Their main function is to straighten the knee and hip. Imbalances or weakness in this muscle group may result in deviations of the kneecap, which may result in the pain experienced.
People who are physically less fit are also more susceptible to PFPS. Studies found that individuals who participate in sports more hours per week and can accomplish a higher vertical jump are less likely to develop PFPS in the future. The protective role of prior sports participation can be attributed to greater quadriceps strength, therefore reducing the risk of PFPS development.
The flexibility of gastrocnemius and quadriceps are also risk factors for PFPS. One study found that decreased flexibility of the gastrocnemius and quadriceps increases one’s likelihood of developing PFPS.
Contrary to popular belief, a greater quadriceps angle (Q-angle) does not significantly contribute to PFPS. The Q-angle is the angle formed between the quadriceps muscle and the patella tendon. It measures the pull exerted by the outer side of the knee on the kneecap. Studies have found no significant difference between the Q-angles of those who will develop PFPS in future and those who will not.
The relationship between the onset timing of the vasti muscles and PFPS is also unknown. The vasti muscles are a group of three muscles that are part of the quadriceps. Delayed activation of the individual vastus muscles was originally thought to have contributed to PFPS. However, contradictory findings from different studies make it difficult to conclude the association between the activation of the vasti muscles and the development of PFPS.
Why is it important to know who is at risk?
There is a high incidence of PFPS amongst the athletic, military and general populations. Incidence rates of PFPS in sports medicine and basic military training are between 25% and 43%. While the incidence rate of PFPS in the general population remains undiscovered, a general practitioner sees an average of five to six new patients for PFPS yearly.
Prevention is better than cure. Being able to identify individuals who are at a higher risk of developing PFPS is the first and important stepping stone toward PFPS prevention. By targeting the high-risk groups, exercise programmes aimed at quadriceps muscle strengthening and flexibility can help to reduce the incidence of PFPS.
How can I reduce the pain in the front of my knee?
Since weak quadriceps muscle increases the risk of PFPS development, an exercise programme targeted at strengthening the quadriceps muscle is an effective way to prevent PFPS and the pain at the front of the knee. A study found that a supervised exercise therapy programme that includes quadriceps training is effective for the treatment of PFPS. Strength training for those who tend to have short periods of overuse, such as athletes and military recruits is recommended. Individuals at higher risk for PFPS, especially females, are also advised to start exercises that focus on quadriceps strengthening.
Exercises for strengthening the quadriceps muscles are simple to do and do not require much equipment, hence they can be done whenever it is convenient. Some examples of the exercises includes, but not limited to:
However, before embarking on any exercise programme, it is important to take into account the physical activities that are already being performed, as well as the response to the exercise.
Lankhorst, N., Bierma-Zeinstra, S., & van Middelkoop, M. (2012). Risk Factors for Patellofemoral Pain Syndrome: A Systematic Review. Journal Of Orthopaedic &Amp; Sports Physical Therapy, 42(2), 81-A12. https://doi.org/10.2519/jospt.2012.3803
DISCLAIMER: These advise and exercises should not replace the need for a consultation with a Physiotherapist especially if your condition doesn’t improve. Therapeutic exercise should be carefully selected to suit your condition.