What is Patellofemoral Pain Syndrome?
Patellofemoral pain syndrome is a general term to describe pain in the front of the knee. It may also be known as Anterior Knee Pain, Runner’s Knee or Jumper’s Knee.
The knee is a complex joint, made up of the femur (thigh bone), connecting to the tibia and fibula (shin bones). These bones are connected by two ligaments in the middle (Anterior Cruciate Ligament and Posterior Cruciate Ligament) and ligaments on either side (Medial Collateral Ligament and Lateral Collateral Ligament). In between the bones are 2 C-shaped pieces of cartilage that act as shock absorbers for the knee joint (Medial Meniscus and Lateral Meniscus). There are a number of other structures within the knee joint that can also be irritated and lead to knee pain (bursae and fat pads). On top of the knee joint is the kneecap (patella) which has the quadricep muscle sitting on top and the patella tendon underneath it. On the inside of the knee are the groin muscles (adductors) and on the outside of the knee is the Iliotibial Band (ITB). The hamstring and calf muscles support the back of the knee joint.
What can cause pain in the front of my knee?
- Chondromalacia Patellae: This is the softening of the articular cartilage underneath the kneecap. This can lead to inflammation of the synovium (lining of the joint, also known as synovitis) or bone pain.
- Tendinopathy: There are two tendons in the knee that can become irritated – the quadriceps, which sits above the kneecap, or most commonly, the patella tendon, which sits below the knee cap. Tendons can either be classified as acute reactive, meaning that an overload to the knee can result in changes to the tendon structure, causing pain. Alternatively, tendons can also be degenerative, meaning that over time, stress to the tendon causes it to weaken. Tendon pain is often characterised as pain that is present when you start exercising and then goes away for the remainder of the exercise, only to return later that day or the next day. It can be quite sore to touch also.
- Hoffa’s Fat Pad Impingement: The fat pad is a soft-tissue structure which sits underneath the kneecap. It has a lot of nerve endings and if irritated it can become swollen and very painful. This can cause pain when putting weight through the leg in standing or bending/straightening movements of the knee.
- Bursitis: The bursa is a small sack of fluid which sits just under the knee cap.When irritated this too can swell and lead to a lot of pain.
- Osteoarthritis: There are many different types of arthritis, however, osteoarthritis is the most common and most apparent in people over the age of 40. It is essentially the breakdown of cartilage that covers the ends of bones within a joint. It is something that generally develops over time and may present as pain and stiffness and may have some associated ‘clicking’ sensations with it.
- Patellofemoral tracking: When we bend and straighten the knee, the kneecap should move smoothly in the groove in the bones that it sits in. If there is muscle tightness or weak muscles, this may impact how smoothly it moves, and can further irritate some of the other structures sitting underneath it.
What leads to knee pain?
There are a number of factors that can cause knee pain. This can include:
- Overload – this may be the result of changing the type of exercise you do or increasing how many times a week or for how long you are exercising for. It may also be related to changes in occupation that require you sit or stand more during the day.
- Muscle weakness – not having adequate strength in any muscle from the hip down can place more stress on the joint. Strong muscles are able to absorb force with our day-to-day activities placing less stress through the joint
- Muscle imbalance – this is where there may be an imbalance between the strength of the muscles in the front versus the back of the leg. Quite often, those who are more quadricep ‘dominant’ can be more likely to have increased pressure on the front of the knee joint.
- Muscle tightness – tight quadriceps muscles on the top of the knee or tightness in the ITB can place extra load on the front of the knee, resulting in pain.
- Exercise or running technique – poor technique and control around the knees with activities such as squatting, jumping, running or hopping may result in force not being evenly distributed throughout the whole knee
- Weight – carrying excess body weight can put unnecessary strain on the knee joint
- Footwear – shoes that do not provide good stability for the foot during exercise can result in more force radiating up to the knee.
What are the symptoms of patellofemoral knee pain?
Patellofemoral knee pain is generally characterised by pain at the front of the knee. This can be diffuse, and spread across the whole knee, may be difficult to locate, may vary in location or may be quite specific. The pain is quite often an ache, that can be aggravated by weight bearing exercises such as walking, stairs or running or flexion-based activities such as squatting or kneeling. There may or may not be some associated swelling and clicking/clunking or grinding.
Who is at the most risk of developing knee pain?
- Inactive/sedentary individuals
- Individuals participating in a high-volume of physical activity
How can a physiotherapist help me with my knee pain?
Your physiotherapist will first take a detailed history of when the pain started, what causes it, what helps it and any other previous injuries.
They will then assess the knee which may include:
- Strength testing of hamstrings, quadriceps, calves, gluteals and core
- Flexibility of muscle groups from the hips down
- Single leg control and stability
- Functional assessment of the particular movements causing you pain i.e. stairs, jumping etc
- Special tests if there is suspected injury to the ligament or meniscus
- Running assessment
Once your physiotherapist has identified the contributing factors to your knee pain, they will discuss the best possible management plan for you. This may include:
- Advice on initial pain management which may include icing, taping/ bracing, resting
- Massage around the knee in the early stage to help settle pain
- Stretching or foam rolling exercises
- Strengthening exercises
- Reviewing your current exercise routine for the week and education on load management
- Referral to our podiatrists to assess whether footwear or issues with the feet may be contributing to your pain
- A return to sport/exercise program
Will I have to stop exercising because of my knee pain?
Every individual is different, however, we understand the importance of keeping up physical activity from a physical, mental and emotional perspective, especially if you are in the middle of a sporting season or have a specific event or holiday coming up. Our goal is always to work with you and if we can see that the knee is being overloaded, we will find a way to either modify the type or amount of exercise you do in the short-term, so we can return you to your ideal activity in the long-term.
As physiotherapists we know that for most knee injuries, we need to find the optimal load meaning that complete rest can be just as bad as doing too much and pushing through the pain.
The best evidence supports specific strengthening exercises as one of the best ways to treat knee pain both short- and long-term.
Do I need a scan for my knee?
Generally, a scan is not necessary for the management of knee pain and more often than not, the findings will not necessarily change the plan for treatment. If your physiotherapist is concerned that there may be damage deeper within the knee, or if your injury is not improving within the first 4 appointments, they will be able to organise a referral for further investigation.
How can I prevent knee pain?
There are a number of things you can try to do yourself before seeking expert help.This could include:
- Weight loss: Studies have shown that even 10% loss of your body weight can result in a 50% improvement in knee pain and function (Stephen et al. 2018)
- Strength Training: As well as aerobic exercises such as running, it is important that you maintain some strength in all muscle groups around the knee.
- Footwear: Getting a shoe fitting from your podiatrist or a store that specialises in footwear for exercise can help ensure you have the best pair of shoes for your foot shape and activity. Otherwise, ensuring that you are doing your shoelaces up nice and tight and replacing old, worn out shoes can also have a big impact on knee pain.
- Warm Up and Cool Down: Spend some time warming up the muscles you are about to use for that activity and spending some time stretching/foam rolling/releasing those muscles after exercise.
- Gradually overload: Whether you have not done a particular form of exercise for a while or are wanting to increase your current training, gradually increase the number of sessions per week and intensity of the exercise over time, not all at once.