Knee Pain? Why Your Knee Hurts: Patellofemoral Pain Syndrome Medical Steps

Knee pain is one of the most common musculoskeletal complaints in adults and adolescents. If your pain is located in the front of your knee—especially around or behind the kneecap—patellofemoral pain syndrome (PFPS) may be the cause.

Patellofemoral pain syndrome is sometimes called "runner's knee," but it doesn't just affect athletes. It can develop in anyone who places repeated stress on the knee joint. The good news? In most cases, it improves with the right steps.

Below is a medically grounded, easy-to-understand guide to what patellofemoral pain syndrome is, why it happens, and what you can do about it.

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What Is Patellofemoral Pain Syndrome?

Patellofemoral pain syndrome is pain that occurs when the underside of your kneecap (patella) becomes irritated as it moves against the thigh bone (femur).

The kneecap sits in a groove at the end of your femur. When you bend or straighten your knee, the kneecap glides up and down in that groove. If the kneecap does not move smoothly—due to muscle imbalance, overuse, or alignment issues—it can cause irritation and pain.

PFPS is considered a diagnosis of exclusion, meaning your doctor may rule out other structural problems before confirming it.

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Common Symptoms of Patellofemoral Pain Syndrome

People with patellofemoral pain syndrome often describe:

• Dull, aching pain in the front of the knee
• Pain behind or around the kneecap
• Pain that worsens with:
  • Climbing or descending stairs
  • Squatting
  • Running
  • Kneeling
  • Sitting for long periods with bent knees ("movie theater sign")
• A grinding or popping sensation in the knee

Swelling is usually mild or absent. Significant swelling may suggest a different condition.

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What Causes Patellofemoral Pain Syndrome?

PFPS is usually caused by a combination of mechanical and overuse factors.

1. Overuse

Repetitive knee bending—especially during running, jumping, or squatting—places stress on the patellofemoral joint.

2. Muscle Imbalance or Weakness

Weakness in key muscle groups can change how the kneecap tracks:

• Quadriceps (front of thigh)
• Hip abductors (outer hip)
• Core stabilizers

When these muscles are weak, the kneecap may drift slightly out of alignment.

3. Poor Biomechanics

• Flat feet or overpronation
• Tight hamstrings or calf muscles
• Abnormal kneecap alignment

4. Sudden Increase in Activity

Rapidly increasing running mileage or intensity is a common trigger.

5. Trauma

A direct blow to the knee can sometimes lead to PFPS symptoms.

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Who Is at Risk?

Patellofemoral pain syndrome is more common in:

• Runners and athletes
• Teens and young adults
• Women (due to hip and pelvic structure differences)
• People who recently changed their exercise routine
• Individuals with previous knee injuries

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How Is Patellofemoral Pain Syndrome Diagnosed?

A healthcare provider will typically diagnose patellofemoral pain syndrome through:

Medical History

You'll be asked about:

• Activity levels
• Recent changes in exercise
• Location and pattern of pain
• Previous injuries

Physical Examination

Your doctor may:

• Press on the kneecap
• Evaluate how your knee moves
• Assess muscle strength and flexibility
• Watch how you walk or squat

Imaging

X-rays or MRIs are not always necessary. They are typically used to rule out:

• Fractures
• Arthritis
• Cartilage damage
• Ligament injuries

If your knee pain is accompanied by morning stiffness, affects multiple joints, or you're concerned it may be arthritis-related rather than PFPS, you can use Ubie's free AI-powered Osteoarthritis (OA) symptom checker to help determine if arthritis could be playing a role in your symptoms.

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Medical Steps for Patellofemoral Pain Syndrome

The treatment for patellofemoral pain syndrome is usually conservative (non-surgical). Most people improve with structured rehabilitation and activity adjustments.

1. Activity Modification

This does not mean complete rest—but you may need to:

• Reduce high-impact activities
• Avoid deep squats or lunges temporarily
• Cut back running mileage
• Switch to low-impact exercise (cycling, swimming)

The goal is to calm irritation while staying active.

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2. Physical Therapy

Physical therapy is the cornerstone of PFPS treatment.

A structured program typically focuses on:

• Quadriceps strengthening
• Hip abductor strengthening
• Core stability work
• Stretching tight hamstrings, calves, and hip flexors
• Gait and movement correction

Research consistently shows that strengthening the hip and thigh muscles improves patellofemoral tracking and reduces pain.

Commitment matters. Exercises often need to be done several times per week for 6–12 weeks.

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3. Ice and Anti-Inflammatory Measures

To reduce discomfort:

• Apply ice for 15–20 minutes after activity
• Elevate the leg when possible
• Use nonsteroidal anti-inflammatory drugs (NSAIDs) if recommended by your doctor

Medication should be short-term unless guided by a healthcare provider.

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4. Patellar Taping or Bracing

Some patients benefit from:

• Patellar taping techniques
• Knee braces designed to improve alignment

These are usually temporary supports—not permanent fixes.

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5. Footwear and Orthotics

If foot alignment contributes to poor knee tracking:

• Supportive running shoes may help
• Custom or over-the-counter orthotics can reduce strain

A gait evaluation by a physical therapist or sports medicine provider can be helpful.

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6. Gradual Return to Activity

Once pain improves:

• Increase intensity slowly
• Follow the "10% rule" (no more than 10% weekly increase in training load)
• Continue strengthening exercises even after symptoms resolve

Stopping exercises too early is a common reason symptoms return.

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When Is Surgery Needed?

Surgery for patellofemoral pain syndrome is rare.

It may be considered only when:

• Symptoms persist for many months despite structured rehab
• There is clear structural malalignment
• Imaging shows cartilage damage or other abnormalities

Most people never need surgery.

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What Happens If You Ignore It?

PFPS is not usually dangerous, but ignoring persistent knee pain can:

• Prolong recovery
• Lead to altered movement patterns
• Increase risk of other injuries
• Potentially contribute to long-term joint irritation

Addressing it early improves outcomes.

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How Long Does Recovery Take?

Recovery varies based on:

• Severity of symptoms
• Adherence to rehab
• Underlying biomechanical factors

Many people improve within 6–12 weeks. Chronic cases may take longer but still respond to consistent treatment.

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When to Speak to a Doctor Immediately

While patellofemoral pain syndrome is generally not life-threatening, you should seek urgent medical attention if you experience:

• Severe swelling
• Inability to bear weight
• Fever with knee pain
• Sudden deformity
• Knee locking or giving out repeatedly
• Signs of infection (redness, warmth, fever)

These symptoms may indicate a more serious condition.

Always speak to a doctor if your pain is persistent, worsening, or interfering with daily life.

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The Bottom Line

Patellofemoral pain syndrome is a common cause of front-of-knee pain. It usually develops from overuse, muscle weakness, or poor kneecap tracking. While frustrating, it is highly treatable with:

• Activity modification
• Targeted strengthening
• Flexibility work
• Gradual return to activity

Most people recover without surgery.

If your knee pain feels different than typical PFPS—or if you're concerned about arthritis—you can use Ubie's free AI-powered Osteoarthritis (OA) symptom checker to get personalized insights about your symptoms and whether arthritis may be a factor.

Knee pain should not be ignored. The earlier you address it, the better your outcome. If you're unsure about your symptoms, or if anything feels severe or unusual, speak to a qualified healthcare professional promptly.