Patellofemoral Pain Syndrome (PFPS)
1. Introduction
Patellofemoral pain syndrome (PFPS) is a common condition that is defined by pain located around or behind the kneecap. The kneecap sits in a special groove at the front of the femur known as the trochlea groove. The kneecap helps us to bend and straighten our knees more effectively. Patellofemoral pain syndrome is a general term that describes pain in the front of or behind your knee, or around your kneecap (patella) (1). Patellofemoral pain syndrome is also called ‘runner’s knee’ and anterior knee pain syndrome (5,4). It is a common, non-serious cause of knee pain that is usually linked to overuse rather than injury. It is often seen in younger adults who participate in sports, although anyone can be affected, including those who are sedentary.
Frequently Asked Questions
- Patellofemoral pain syndrome (PFPS) is defined as pain behind or around the kneecap (patella).
- Common.
- Patellofemoral pain syndrome is a common cause of knee pain in adolescents and young adults, especially among those who are physically active and regularly participate in sports such as running.
- It occurs in approximately 22% of the general population and 29% of adolescents (8).
- Patellofemoral pain syndrome is also called ‘runner’s knee’ and anterior knee pain syndrome (5)(4).
- No.
- With the right rehabilitation approach patellofemoral pain syndrome generally recovers well (1).
- Patellofemoral pain syndrome is not linked to other serious pathology.
- It most often affects young adults, typically those who run or are involved in sports such as football or basketball and running (7, 8).
- Common between the ages of 14-40.
- While the exact cause is unclear, it is believed to be due to overuse.
- Risk factors include trauma, increased training and weaker muscles around the knee and hip.
- Pain at the front of the knee, around and behind your kneecap.
- The onset of symptoms can be slow with worsening pain with certain activities.
- Pain going up and down stairs.
- Prolonged sitting can aggravate the pain.
There are many things you can do to help recover:
- Modify or reduce activities that cause pain.
- Take simple pain relief if it helps manage your symptoms.
- Exercise therapies are most effective in improving short and long-term pain in patients with patellofemoral pain syndrome.
- Outcomes of physiotherapy-led treatment for patellofemoral pain syndrome are overwhelmingly positive.
- With appropriate actions taken at an early stage, functional recovery is very good.
- Complete recovery and return to sport may take several months depending on the severity of your pain.
We recommend consulting a musculoskeletal physiotherapist to ensure exercises are best suited to your recovery. If you are carrying out an exercise regime without consulting a healthcare professional, you do so at your own risk.
2. Signs and Symptoms
The onset of the condition is usually gradual, although some cases may appear suddenly following a trauma. The typical signs and symptoms of patellofemoral pain syndrome include:
- Pain at the front of the knee or behind the kneecap.
- Pain that is aggravated by activities such as ascending and descending stairs, sitting with knees bent, kneeling, and squatting.
- Patients may report a sensation of grinding or clicking from the affected knee.
- There may be mild swelling, but often no visible bruising, heat or redness (5).
3. Causes
Patellofemoral pain syndrome is very rarely linked to a direct injury to the knee. Most often it develops gradually because of increased loads placed upon the knee, combined with biomechanical factors such as having flat feet (over-pronation) or tighter muscles (such as the hamstrings and quadriceps). The combination of increased load on the area and biomechanical changes can result in overload and sensitisation of the surface of the kneecap that sits within the trochlea groove. It used to be felt that the cause of pain was weakness or softening of the cartilage that lines the back of the kneecap. However, recent research has shown physical signs identified on imaging have poor correlation with the person’s levels of activity, pain and disability (7).
4. Risk Factors
This is not an exhaustive list. These factors could increase the likelihood of someone developing patellofemoral pain syndrome. It does not mean everyone with these risk factors will develop symptoms.
- Increased knee joint loads – e.g. in sporting activities such as running, climbing, jumping and sport.
- Reduced muscle strength – in muscles that support and stabilise the knee, such as the quadriceps and stabiliser muscles of the pelvis.
- Biomechanical factors that affect the alignment of the knee – such as having flat feet or fallen arches.
- Training errors – such as inadequate periods of rest and recovery for those that participate in sport (4).
5. Prevalence
Patellofemoral pain syndrome is a common cause of knee pain in adolescents and young adults, especially among those who are physically active and regularly participate in sports. Patellofemoral pain syndrome is also called ‘runner’s knee’ and anterior knee pain syndrome (4,5).
6. Assessment & Diagnosis
Musculoskeletal physiotherapists and other appropriately qualified healthcare professionals can provide you with a diagnosis by obtaining a detailed history of your symptoms. A series of physical tests might be performed as part of your assessment to rule out other potentially involved structures and gain a greater understanding of your physical abilities to help facilitate an accurate working diagnosis. Identification of various intrinsic and extrinsic factors that lead to patellofemoral pain syndrome will guide your treatment plan.
Your treating clinician will want to know how your condition affects you day-to-day so that treatment can be tailored to your needs and personalised goals can be established. Intermittent reassessment will ascertain if you are making progress towards your goals and will allow appropriate adjustments to your treatment to be made. Imaging studies like an MRI or ultrasound scan are usually not required to achieve a working diagnosis, but in unusual presentations, they may be warranted.
7. Self-Management
As part of the sessions with your physiotherapist, they will help you to understand your condition and what you need to do to help the recovery from your patellofemoral pain syndrome. This may include reducing the amount or type of activity, as well as other advice aimed at reducing your pain. It is important that you try and complete the exercises you are provided as regularly as possible to help with your recovery. Rehabilitation exercises are not always a quick fix, but if done consistently over weeks and months then they will, in most cases, make a significant difference.
8. Rehabilitation
Physiotherapist led rehabilitation is the gold-standard treatment for patellofemoral pain syndrome. The aims of rehabilitation are to identify which factors are influencing your knee joint pain and correct these with exercise. This may involve exercises to help strengthen the hip and knee region, and improve the flexibility of your hamstrings, calves and quadriceps. The physiotherapist may also discuss the most appropriate ways to reduce pain during your activities and discuss a phased return to your sport to minimise the chances of this problem recurring.
9. Patellofemoral Pain Syndrome (PFPS)
Rehabilitation Plans
Our team of expert musculoskeletal physiotherapist have created rehabilitation plans to enable people to manage their condition. If you have any questions or concerns about a condition, we recommend you book an consultation with one of our clinicians.
What Is the Pain Scale?
The pain scale or what some physios would call the Visual Analogue Scale (VAS), is a scale that is used to try and understand the level of pain that someone is in. The scale is intended as something that you would rate yourself on a scale of 0-10 with 0 = no pain, 10 = worst pain imaginable. You can learn more about what is pain and the pain scale here.
These are some simple strengthening exercises for the quadriceps and hip stabiliser muscles. These exercises can be performed one to two times per day. It is safe and normal to have some discomfort in the knee, but these are low-level exercises that should be non-provocative. Pain should not exceed 4/10 on your perceived pain scale whilst completing this exercise programme.
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- 910
These are some more advanced exercises that will aim to strengthen and mobilise the hip and knee joint in more functional positions, such as standing. The aim is to improve the strength and stability of key muscles that support your knee during functional activities. This programme can be performed every other day. As these exercises are performed in a weight-bearing position, it is safe and normal to have some low-level discomfort during these exercises. Pain should not exceed 4/10 whilst completing this exercise programme.
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- 910
These are some more advanced strengthening exercises that aim to strengthen the muscles in more demanding positions to prepare you for a return to sport or physical activity. These exercises should be performed 2-3 times per week like a gym programme as we must consider at this stage you may be preparing to return, or have even returned, to sport. Pain should not exceed 4/10 whilst completing this exercise programme.
- 0
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- 910
10. Return to Sport / Normal life
For patients wanting to achieve a high level of function or return to sport, we would encourage a consultation with a physiotherapist as you will likely require further progression beyond the advanced rehabilitation stage. Before returning to sport, a rehabilitation programme should incorporate plyometric-based exercises; this might include things like bounding, cutting, and sprinting exercises (5,7).
As part of a comprehensive treatment approach, your musculoskeletal physiotherapist may also use a variety of other pain-relieving treatments to support symptom relief and recovery. Whilst recovering you might benefit from a further assessment to ensure you are making progress and establish the appropriate progression of treatment. Ongoing support and advice will allow you to self-manage and prevent future reoccurrence.
11. Other Treatment Options
Podiatry referral to address bio-mechanical issues in your feet may be helpful in the short term. However, there is a lack of quality evidence in regards to long-term value when it comes to patellofemoral pain syndrome. In the extremely unlikely scenario that performing your rehabilitation and modifying your activity does not settle your symptoms, you may be referred to see an orthopaedic surgeon (a doctor who specialises in the treatment of bone and joint disorders).
12. Links for Further Reading
References
- Witvrouw E, Callaghan MJ, Stefanik JJ, et a (Sep 2013). Patellofemoral pain: consensus statement from the 3rd International Patellofemoral Pain Research Retreat held in Vancouver. Br J Sports Med. 2014 Mar;48(6):411-4. doi: 10.1136/bjsports-2014-093450.
- Collado H, Fredericson M; Patellofemoral pain syndrome. Clin Sports Med. 2010 Jul;29(3):379-98. doi: 10.1016/j.csm.2010.03.012.
- Anterior Knee Pain; Arthritis Research UK, October 2004.
- Willy, R.W., Hoglund, L.T., Barton, C.J., Bolgla, L.A., Scalzitti, D.A., Logerstedt, D.S., Lynch, A.D., Snyder-Mackler, L., McDonough, C.M. (2019). Patellofemoral Pain. J Orthop Sports Phys Ther 49, CPG1–CPG95. https://doi.org/10.2519/jospt.2019.0302.
- Gaitonde, D.Y., Ericksen, A., Robbins, R.C. (2019). Patellofemoral Pain Syndrome. AFP 99, 88–94.
- Effectiveness of conservative treatment for patellofemoral pain syndrome: A systematic review and meta-analysis [WWW Document], n.d. https://doi.org/10.2340/16501977-2295.
- Barton, C.J., Lack, S., Hemmings, S., Tufail, S., Morrissey, D. (2015). The ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’: incorporating level 1 evidence with expert clinical reasoning. Br J Sports Med 49, 923–934. https://doi.org/10.1136/bjsports-2014-093637.
- Smith BE, Selfe J, Thacker D, et al. (2018). Incidence and prevalence of patellofemoral pain: A systematic review and meta-analysis. PLoS One.13(1):e0190892. Published 2018 Jan 11. doi:10.1371/journal.pone.0190892.
Other Conditions in
Knees
Patellar Tendinopathy
Knee pain at the lower border of the kneecap which is also known as ‘jumper’s knee’.
Osgood-Schlatter Disease
Pain in an area just below the knee on the shin bone, often with a lump.
Meniscus Injury
Structural knee injury, triggered either by a tear or through wear and tear.
Knee Replacement Surgery
Replacement of the knee hinge joint, typically as a result of severe osteoarthritis or trauma.
Knee Osteoarthritis
Common age related changes to the structure of the knee joint which may be associated with pain, stiffness and loss of function.
Iliotibial Band Syndrome
Presents as pain on the outside of the knee, normally occurring because of overload due to prolonged or repeated bouts of exercise.
Femoral Nerve Radiculopathy
This is where the nerve that supplies the front of the leg is irritated and causes pain/numbess.
Fat Pad Impingement
A rare condition affecting the adipose (fat) tissue that sits under the kneecap (patella) between the joint spaces of the knee.
Degenerative Meniscus
Seen to be normal as we age, but in some situations can result in knee aches, pain or joint swelling.
Bowed Knees
A condition in which the legs are bowed outwards leaving a greater space in between your knees.
Benign Joint Hypermobility Syndrome
Common age related changes to the structure of the knee joint which may be associated with pain, stiffness and loss of function.
Baker’s Cyst
Swelling in the popliteal space (space behind the knee) that causes a visible lump.
Anterior Cruciate Ligament (ACL) Injury
Injury to a major stability ligmant in the knee, normally occuring following a significant twisting injury.