Runner’s knee, also known as patellofemoral pain syndrome (PFPS) or anterior knee pain, is a common overuse injury that causes pain around or behind your kneecap/patella. It often results from abnormal patellar tracking within the femoral groove, leading to irritation of the surrounding structures.
As the name suggests, running is often the cause of runner’s knee, but it is also quite common in non-athletes. Almost 25% of the world’s population have some form of knee pain, more specifically pain in the area of the kneecap.
The anatomy of the patellofemoral joint
The patellofemoral joint is where your patella articulates with the femur, or thigh bone. It plays a crucial role in knee extension by enhancing the mechanical advantage of the quadriceps muscle, acting as a pulley to improve the transfer of force. You’ll find the patella, or kneecap, at the front of your knee joint. It’s a small, triangular bone that is embedded within the quadriceps tendon.
Key anatomical structures around the patella include:
– Quadriceps Tendon: Connects the quadriceps muscles to the patella.
– Patellar Ligament (Tendon): Extends from the patella to the tibial tuberosity on your shin bone, helping in knee extension.
– Articular Cartilage: Covers the underside of the patella, allowing smooth movement over the femur, or thigh bone.
– Retinacula (Medial & Lateral): Fibrous structures, similar to ligaments, that help stabilize your patella.
– Synovial Bursa: Reduces friction between the patella and surrounding structures.
What should happen in and around my knee when I move?
Your patella moves within a groove of your thigh bone when you bend or straighten your knee, called patellofemoral tracking. This movement is guided by ligaments around the knee cap and various muscles working together. Pressure on the patellofemoral joint increases when you bend your knee and is at its highest about about 60-90° of flexion. Fortunately, all the structures around your patella are specifically designed to handle this pressure.
Now I have runner’s knee. What went wrong?
Runner’s knee is caused by abnormal tracking of the patella (kneecap) over the femur, leading to increased stress and irritation of the patellofemoral joint.
Tight structures around your knee joint increases strain put on the patella causes a compression in the femoral groove. The higher the load on your quadriceps, the greater the compression on the patella. The excessive pull on the quadriceps tendon on the top part of the patella can start tearing the tendon fibers. If there is an imbalance of the quadriceps muscles, it can cause a sideways pull on your patella, which also leads to abnormal tracking when you move your knee .
The downwards compression of the back part of the patella onto the thigh bone will erode the cartilage over time, reducing its shock-absorbing function. This compression force is exacerbated when the quadriceps muscle is shortened. Abnormal patellar movement lead to excessive friction and pressure on the underlying cartilage. This causes microtrauma, inflammation, and pain, especially with repetitive knee flexion (e.g., running, squatting).
Causes of runner’s knee
- Overuse and Repetitive Stress
- Excessive training without proper recovery
- Muscle Imbalances and Weakness
- Poor Running Form or Biomechanics
- Foot Problems and Improper Footwear
- Tight Muscles and Limited Flexibility
- Previous Knee Injuries
- Hard or Uneven Running Surfaces
- Sudden Increases in Training Intensity
- Excess Body Weight
Runner’s knee affects 25-30% of runners.
I have runner’s knee – how bad is it?
At first you will have a dull, aching pain around or behind your kneecap, typically triggered by activities like running, squatting, or climbing stairs. Pain comes and goes, usually relieved by rest, and you will have some stiffness or discomfort around your knee after prolonged sitting. For now, your knee joint doesn’t feel unstable, and pain doesn’t affect your day to day activities, but you may notice occasional cracking or popping of your knee.
As the problem gets worse, pain becomes more persistent and occurs even during low-impact activities like walking or going down stairs. Now you may notice swelling and inflammation around your patella, and your knee starts to feel weak and unstable. Discomfort lingers after exercise, requiring longer recovery periods. The feeling of grinding (crepitus) under your kneecap becomes more noticeable and running or jumping will become increasingly difficult.
In the severe stage, pain is constant, even at rest. Your knee feels stiff and swollen most of the time, and you’ll have sharp pain with even simple movement like bending your knee or standing up. At this point, untreated runner’s knee will severely limit daily activities like driving and walking, requiring medical intervention and rehabilitation.
Diagnosis
Physiotherapy diagnosis
Physiotherapists are experts in human anatomy and movement, so we will analyze the problem from all sides. Part of this is taking a complete history and doing a physical examination. We test the joint, ligaments and muscles around your knee and will also look at other contributing factors, like weakness in your hip muscles or perhaps ankle stiffness. These clinical tests give us more information about your problem to make a diagnosis.
X-rays
Muscles cannot be seen on an x-ray, so it will not be helpful to diagnose runner’s knee. X-rays will however show the integrity and alignment of joints in your knee.
Your physiotherapist can refer you to get x-rays taken if necessary.
Diagnostic ultrasound
Diagnostic ultrasound can be used to show the presence of a muscle tear (muscle strains), inflammation, swelling or simply increased contraction of a muscle (muscle spasms).
If you need an ultrasound, your physio will refer you.
MRI
An MRI scan can image all of the structures in your knee, including soft tissue, nerves and bones. However, for runner’s knee, an image like this is unnecessary and very expensive.
Why is my knee pain not going away?
- Increased Joint Stress: Without addressing the underlying biomechanical issues (e.g., muscle imbalances, poor tracking of the patella), repetitive stress on the kneecap’s cartilage continues.
- Synovitis: Persistent irritation of the joint can lead to chronic inflammation of the synovial membrane (synovitis), which produces joint fluid. This inflammation contributes to ongoing pain and swelling.
- Muscle Atrophy/Weakness: Pain and reduced activity can lead to disuse atrophy and weakness of key stabilizing muscles around the knee and hip (e.g., quadriceps, gluteus medius). This further compromises knee stability and function, perpetuating the problem.
- Tendinopathies: The altered biomechanics and increased stress can lead to the development of other overuse injuries, such as patellar tendinopathy (jumper’s knee) or iliotibial band syndrome.
- Stress Fractures: In severe cases of altered loading patterns, increased stress on bones can even lead to stress fractures.
What NOT to do
Making it worse
Should I do squats to fix my runner’s knee?
Although squats are fantastic for building all-over leg strength, these are not great for when you’re experiencing knee pain because they require deep bends of the knee. Instead of bending your knees to start the squad, imagine you’re sitting down in a chair. This causes you to push your hips and upper body back first, releasing some of the tension on your knees. When your thighs are parallel to the floor, make sure your weight is over your heels rather than your toes.
What about lunges?
This is another one you shouldn’t attempt when experiencing knee pain, but should include when you are not in pain. Be sure to keep your core engaged and as you step forward, try to think of your hips moving down towards the floor rather than forwards. Your knee may not go over the line of your toes. Try doing it against a wall until you’re comfortable.’
Problems we see when patients come to us with runner’s knee
Chronic Pain and Discomfort
The pain around the kneecap (patella) may become persistent, making everyday activities like walking, climbing stairs, or even sitting for long periods uncomfortable. The condition can worsen, leading to increased inflammation and sensitivity in the knee joint.
Cartilage Damage (Chondromalacia Patellae)
Continuous friction between the patella and the femur may lead to softening and breakdown of the cartilage underneath the kneecap. This damage is often irreversible, causing long-term pain and difficulty in movement. This prolonged stress can lead to the softening and breakdown of the articular cartilage on the underside of the patella, a condition known as chondromalacia patellae.
Reduced Mobility and Weakness
Untreated runner’s knee can lead to muscle imbalances, particularly in the quadriceps and surrounding muscles. Weakness in these muscles may further strain the knee, making it difficult to return to physical activities.
Increased Risk of Knee Osteoarthritis
Prolonged misalignment and stress on the knee joint may contribute to early-onset osteoarthritis, a degenerative joint disease that causes stiffness, swelling, and chronic pain. This can significantly impact mobility and quality of life in the long run.
Altered Movement Patterns (Compensatory Injuries)
To avoid knee pain, a person may unconsciously change their walking or running gait, which can put extra strain on other joints, such as the hips, ankles, and lower back. This can lead to secondary injuries, including hip bursitis, Achilles tendinitis, or lower back pain. To avoid pain, individuals often alter their gait or movement patterns, leading to compensatory movements in other joints (e.g., hip, ankle). This creates new problems or exacerbates existing imbalances.
Loss of Athletic Performance
Without proper treatment, athletes or active individuals may struggle with reduced endurance, speed, and agility due to persistent knee pain and instability.
Physiotherapy treatment
Physiotherapy plays a crucial role in treating Runner’s Knee (Patellofemoral Pain Syndrome) by addressing pain, correcting movement dysfunctions, and strengthening the knee for long-term recovery. A physiotherapist’s expertise ensures a personalized and structured approach to rehabilitation. We aim to identify the core structures contributing to your pain. Treatment includes a variety of techniques to desensitize the irritation on the soft tissue, depending on your specific problem. With pain relief, strengthening, mobility work, and movement correction, physiotherapists help runners recover faster, prevent reinjury, and return to peak performance.
Remember prevention is better than cure. Speak to the experts in the field and let us guide you through the process.
Phases of rehabilitation
1st Phase: Pain management (weeks 1-2)
During this initial phase, the primary goal is to reduce your acute pain and inflammation. We will start comfortable movement and very gentle exercises. Treatment for pain relief includes myofascial release, electrotherapy like laser, and strapping.
At the end of this phase, you should have minimal swelling, almost no pain at rest and minimal pain with activities like walking.
2nd Phase: Range of movement (weeks 2-4)
In this phase, the focus shifts to improving pain free range of movement of your knee. Another important component is to address control in the muscles around your knee and hip.
By the end of phase 2, you should have full range of movement of your knee, with minimal discomfort at the end of range. Walking should not be painful and you should be climbing steps with little to no pain. You should also be able to activate the correct muscles around your knee with bending and straightening.
3rd Phase: Muscle activation and control (weeks 3 – 5)
The aim in this phase is to improve the strength and endurance of your muscles around, above and below your knee. We also start addressing any underlying movement issues contributing to your knee pain.
After completing phase 3, you should be able to stand up from a chair, climb stairs and jog short distances without pain. You may still have some discomfort at times, but this will settle quickly and not interfere with your day to day activities.
4th Phase: Muscle strength and stability training (weeks 4 – 8)
By now you shouldn’t have pain with normal daily activities. The focus of this phase is further strengthening and stability around your knee, so we will start introducing more compound/complex exercises. These exercises challenge the muscles around your knee and hip, to work towards speed and agility. Exercises that increase pressure and tension around the patellofemoral joint are introduced during this phase, to prepare your knee for higher load activities like running uphill and increases the distance. If you aren’t a runner, this phase is still important. Without strength, stability and endurance, your knee won’t be able to handle activities like walking for a distance on uneven terrain or repetitive bending and straightening, like gardening or tidying up around the house.
At the end of this phase, you should be running without pain. There should be no swelling, tenderness of stiffness around your knee.
5th Phase: Functional training and long-term conditioning (weeks 8+ )
The final, ongoing phase is dedicated to maintaining the improvements you’ve worked for during rehabilitation. We will also implement long-term strategies to prevent recurrence of your knee pain. These strategies include warning signs of possible flare-ups and home exercises. When you reach this stage, your exercises should be challenging enough that you only need to perform the exercise program once or twice a week.
Can I still run if I have runner’s knee?
It’s safer to consult a physiotherapist to accurately diagnose the problem. The sooner you decrease the irritation on the knee, the faster the healing starts. At the first sign of pain, cut back on your mileage and rather focus on interval training. Avoid any speed or pace training requiring fast acceleration and deceleration. No hill or decline runs, it would be safer to run on the treadmill until the knee pain has resolved.
Physiotherapy is the cornerstone of effective treatment for runner’s knee. The healing time can vary, but generally, it ranges from 4-6 weeks for mild cases to 3-6 months or even longer for more severe or persistent cases. This timeline depends on individual factors like chronicity, adherence to the program, severity of the condition, and underlying biomechanical issues.
Other forms of treatment
- General practitioner to prescribe medication for pain relief and management of inflammation, if necessary.
- Chiropractic Care isn’t usually effective for runner’s knee, because the problem is caused by a soft tissue imbalance, not a joint restriction.
- Shockwave therapy
- Platelet-Rich Plasma (PRP) Therapy is still considered experimental for runner’s knee.
- Biokinetics to assist with long-term strength and conditioning after your return to running.
- Hydrotherapy (Water Therapy) reduces joint stress while strengthening muscles, and also helps to maintain mobility and endurance.
- Gait Analysis to determine if abnormal gait (walking) mechanics contribute to your knee pain.
- Custom Orthotics to address foot misalignment, if necessary.
- Corticosteroid Injections may help with pain relief, but will weaken structures around your knee, possibly causing long-term damage.
Is surgery an option?
Surgical management is rarely indicated for runner’s knee, but may be necessary in very specific cases. These cases are usually where there are structural knee problems, like bony malalignment or severe cartilage damage.
Arthroscopic surgery may be indicated to remove damaged cartilage or realign the kneecap. If there is an abnormality of the ligaments around your knee, Lateral Release Surgery can be performed to correct patellofemoral maltracking. In severe misalignment cases, Tibial Tubercle Transfer may be necessary to correct patellar tracking.
As with any surgery, the operation is only the first step. Surgical management will address the structural problem, but not the muscle imbalances around your knee.
What else could it be?
- Iliotibial band syndrome: location of pain is more to the outer part of your knee.
- Knee meniscus tear: deeper pain, and may be accompanied by clicking.
- Knee osteoarthritis: definite morning stiffness that improves with movement.
- Patellar tendinopathy: pain just below your kneecap that gets worse with jumping or climbing stairs.
- Fat pad impingement: knee movement is severely limited due to pain, usually with significant swelling around the kneecap.
Also known as
- Jogger’s knee
- Chondromalacia patella
- Maltracking of patella
- Anterior knee pain
- Patellofemoral pain syndrome
- Kneecap pain
