About Patellofemoral Pain Syndrome

Overview

Patellofemoral pain syndrome (PFPS), also known as runner's knee, is a condition characterized by pain in the front of the knee and around the kneecap. It commonly affects athletes, especially runners and basketball players, but can also occur in non-athletes, adolescents, manual workers, and older adults. PFPS can be caused by overuse of the knee joint, physical trauma, or misalignment of the kneecap. The main symptom is a dull, aching pain in the front of the knee. Diagnosis is typically based on a physical examination and medical history. Treatment for PFPS is usually non-surgical and may include pain medications, activity modifications, physical therapy, and the RICE method (rest, ice, compression, and elevation). Surgery is considered a last resort for severe cases that do not respond to non-invasive treatments.

Causes and Risk Factors

The underlying causes of patellofemoral pain syndrome are not fully understood, but it usually relates to joint issues where the kneecap meets the thigh bone (patellofemoral joint). Several factors have been identified as potential contributors:

Quadriceps muscle weakness: People with PFPS often have weaker quadriceps (thigh) muscles compared to those without the condition. This muscle weakness can lead a decrease in the maximum strength the thigh muscle can produce, which may contribute to the development of PFPS.
Kneecap misalignment: Imbalances in the quadriceps muscles, especially between the inner thigh muscle (vastus medialis oblique) and the outer thigh muscle (vastus lateralis), can make the kneecap tilt more. This misalignment can increase the risk of PFPS.

Non-modifiable risk factors for PFPS, which are factors that cannot be controlled to reduce the risk of developing the condition, include:

Age: Adolescents and young adults are at higher risk of developing PFPS, although older adults can also be affected.
Sex: Women are more likely than men to develop PFPS, possibly due to a higher risk of muscle imbalance and the wider angle of the female pelvis.

Modifiable risk factors for PFPS, which are factors that can be controlled to reduce the risk of developing the condition, include:

Overuse of the knee: Activities that involve repetitive strain on the knee joint, such as running or jumping, can increase the risk of PFPS.
Muscle imbalance: Weakness in certain muscles around the hip and knee can lead to improper alignment of the kneecap, increasing the risk of PFPS.

It's important to note that these factors are not definitive causes or predictors of PFPS. Each individual's situation may vary, and other factors may also play a role. It is recommended to consult with a healthcare professional for an accurate diagnosis and personalized treatment plan.

Symptoms

The most common early symptoms of PFPS include:

Dull, aching pain in the front of the knee
Pain that worsens with activities such as climbing stairs, running, jumping, or squatting
Pain after sitting for an extended period with the knee bent, like watching a movie at a theatre
Cracking or popping sounds in the knee when climbing stairs or after prolonged sitting

As PFPS progresses or becomes more severe, additional symptoms may occur:

Increased pain during exercise or physical activity
Pain when bending the knee, such as when climbing stairs, jumping, or squatting
Persistent pain even at rest
Swelling and inflammation around the knee joint
Limited range of motion in the knee
Weakness or instability in the knee joint

It's important to note that these symptoms can vary from person to person and may not always indicate PFPS. If you experience any of these symptoms, it is recommended to consult with a healthcare professional for an accurate diagnosis and appropriate treatment.

Diagnosis

To diagnose patellofemoral pain syndrome, doctors commonly perform the following examinations, tests, and procedures:

Medical history: Your doctor will ask about your symptoms, general health, and daily functioning.
Physical exam: This involves examining your knee in various positions to assess range of motion and pain. They may also look for signs of injury or muscle loss and listen for crepitus (cracking or grinding sounds).
X-rays: These imaging tests help evaluate the patellofemoral joint, looking for narrowing of joint space, wear and tear on the smooth surfaces of the joint, or the presence of extra bone growths called bone spurs.
Magnetic resonance imaging (MRI) and computed tomography (CT): These imaging tests may be requested to get a more detailed look at the joint. However, if arthritis is suspected as the cause patellar pain, they are generally not needed.

To determine the stage or severity of PFPS, doctors may use imaging tests. Based on how the joint looks with imaging, PFPS is classified into four stages:

Mild: More than 3 millimeters (mm) of joint space
Moderate: Less than 3 mm of joint space but no bony contact
Severe: Bony surfaces are in contact over less than a quarter of the joint
Very severe: Bony contact through the entire joint surface

Remember, these examinations and tests should be performed by a healthcare professional. They will interpret the results and provide appropriate guidance based on your individual situation.

Treatment Options

The goals of treatment for PFPS are to alleviate pain, reduce swelling, improve knee function, and prevent future episodes. Here are the various treatment options and how they work towards achieving these goals:

Medication:
Over-the-counter anti-inflammatory medications (NSAIDs) such as ibuprofen can help reduce pain and swelling associated with PFPS. However, long-term use of NSAIDs should be avoided due to the risk of gastrointestinal problems.
Therapies:
Physical therapy: A qualified physical therapist can recommend exercises, stretches, braces, patella taping, and massage to alleviate symptoms and speed up recovery.
Therapeutic knee and hip exercises: These exercises are considered the most consistent approach for treating PFPS. They can help improve knee function, reduce pain intensity, and increase range of movement.
Therapeutic procedures:
Arthroscopy: This minimally invasive surgical procedure involves removing damaged cartilage and releasing tight tendons to improve knee mobility and relieve tension.
Tibial tubercle transfer: In severe cases, realigning the kneecap by moving the tibial tubercle and patellar tendon can improve knee alignment.
Self-care and health behavior changes:
Activity modification: Avoiding or reducing repetitive high-impact activities like running, jumping, kneeling, squatting, and sitting for long periods can prevent further knee damage and recurrence of PFPS.
RICE protocol: Resting the leg, applying ice packs regularly, using compression bandages, and elevating the knee above heart level can help alleviate pain and swelling.
Wearing supportive footwear: Using orthotics or supportive shoe inserts can provide stability to the foot and ankle.

Remember to consult with your healthcare professional before starting any medication or treatment. Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Side effects can occur. Check with your health care professional or read the information provided with your medication for side effect information.