What Is Chondromalacia Patella? Runner's Knee Symptoms, Causes and Treatment

Created: 13.09.2024 · Last Updated: 12.08.2026 ·  · Prepared by the Academic Hospital Web and Editorial Board.

Chondromalacia patella describes structural softening, surface irregularity or varying degrees of damage to the articular cartilage on the back of the kneecap.

Patellofemoral pain is a clinical pain condition felt around or behind the kneecap and typically aggravated by activities that load the patellofemoral joint, such as running, squatting, climbing stairs, jumping or sitting with the knee bent for a prolonged period. It is often called runner's knee.

Chondromalacia patella and runner's knee are not identical diagnoses. A person with patellofemoral pain may have no significant cartilage damage on MRI, while structural cartilage changes can also be found in people without significant knee pain.

What Is Chondromalacia Patella?

Articular cartilage covers the back of the patella and helps it move with low friction along the trochlear groove of the femur while distributing load through the joint.

Chondromalacia may involve:

  • Cartilage softening
  • Surface irregularity
  • Fissures
  • Partial-thickness cartilage loss
  • Full-thickness cartilage loss in advanced lesions

The term chondromalacia does not by itself explain a person's pain. Pain can arise from pain-sensitive structures around the patellofemoral joint rather than from cartilage itself.

What Is Runner's Knee?

Patellofemoral pain is pain around or behind the kneecap that is aggravated by activities that load the patellofemoral joint.

Although it is often called runner's knee because it is common among runners, it also occurs in non-runners, adolescents and people whose normal activities involve repeated squatting or stair use.

Are Chondromalacia Patella and Runner's Knee the Same Condition?

Not exactly.

Chondromalacia describes structural change in the cartilage behind the kneecap. Patellofemoral pain syndrome is primarily a clinical pain condition defined by symptoms and examination findings.

Therefore:

  • A patient with patellofemoral pain may also have chondromalacia.
  • Patellofemoral pain can occur without significant cartilage damage.
  • Chondromalacia can be visible on MRI in a person who has little or no pain.

This distinction helps avoid basing treatment solely on an MRI appearance.

What Causes Patellofemoral Pain?

There is no single cause. Patellofemoral pain is considered a multifactorial condition.

Contributing factors may include:

  • A rapid increase in running, jumping or squat-based training
  • Sudden changes in training volume or intensity
  • Reduced quadriceps strength or capacity
  • Reduced hip-muscle strength or movement control
  • Patellofemoral anatomy and tracking characteristics in some people
  • Previous patellar dislocation or knee injury
  • Activity loads that exceed current tissue and muscle capacity

A single explanation such as “the kneecap is moving incorrectly” or “the bones are rubbing together” does not accurately describe every patient.

Who Is at Risk?

Patellofemoral pain is particularly common in young and physically active people.

Factors that can be associated with its development include:

  • Participation in running and jumping sports
  • Rapid increases in training load
  • A previous episode of anterior knee pain
  • Certain strength and movement-control characteristics
  • Certain anatomical characteristics

Patellofemoral pain is reported more frequently in females and young female athletes. This cannot be explained simply by lower muscle mass; biomechanics, anatomy, training load and other factors may contribute.

Can Chondromalacia Patella Be Genetic?

Chondromalacia patella and patellofemoral pain are not considered single-gene inherited disorders.

However, inherited anatomical characteristics can influence patellofemoral loading, including:

  • Trochlear shape
  • Patellar position
  • Joint mobility
  • Lower-limb anatomy

Training load, physical activity, previous injuries and muscular capacity also remain important.

What Are the Symptoms?

The characteristic symptom is pain around or behind the kneecap.

Pain can increase with:

  • Going up or down stairs
  • Running
  • Jumping
  • Squatting
  • Kneeling
  • Sitting with the knee bent for long periods

Crepitus or a grinding sensation may also occur. However, joint sounds alone do not prove cartilage damage.

True locking, marked instability, major swelling after trauma or inability to bear weight are not typical features of uncomplicated patellofemoral pain. Other knee conditions may need to be investigated.

What Are the Grades of Chondromalacia Patella?

Patellar cartilage damage can be described using systems such as the classic Outerbridge classification.

  • Grade I: Early cartilage softening and swelling.
  • Grade II: More limited fissures or surface irregularity.
  • Grade III: Deeper or more extensive cartilage fissures and partial-thickness loss.
  • Grade IV: Full-thickness cartilage loss with exposure of underlying subchondral bone.
These are grades of structural cartilage damage, not stages of pain. A higher cartilage grade does not necessarily mean more severe pain, and significant patellofemoral pain can occur without advanced cartilage damage.

How Is Patellofemoral Pain Diagnosed?

Diagnosis is primarily based on medical history and physical examination.

Assessment may include:

  • Location of pain
  • Activities that provoke symptoms
  • Pain during squatting and stair use
  • Knee and hip strength
  • Hip, knee and ankle mobility
  • Movement control during walking, running or squatting
  • The patella and surrounding structures

There is no single physical examination test that definitively diagnoses patellofemoral pain. Findings are interpreted together while considering other causes of anterior knee pain.

Is MRI Always Required?

No. Imaging is not always necessary in a patient with a typical clinical presentation of patellofemoral pain.

X-ray or MRI may be useful when there is:

  • An atypical clinical presentation
  • A history of significant trauma
  • True locking or instability
  • Concern about an osteochondral lesion
  • Persistent symptoms despite appropriate management
  • Consideration of surgery

MRI can assess the patellar and trochlear cartilage, bone marrow, menisci, ligaments and other soft tissues.

Arthroscopy is not a routine diagnostic test for patellofemoral pain. It is not normally required simply to confirm chondromalacia and is considered when there is a separate surgical indication.

How Is Chondromalacia Patella and Runner's Knee Treated?

The first-line approach to patellofemoral pain is usually non-surgical.

Management is built around:

  • Patient education
  • Activity and load management
  • Individualised exercise therapy

Activities that repeatedly provoke significant pain may need to be temporarily reduced, but prolonged complete rest is generally avoided. The aim is to maintain tolerable activity and progressively rebuild capacity.

Appropriate pain-relieving medication can be considered for selected patients after medical assessment.

Patellar Taping and Bracing

Patellar taping may provide short-term pain relief in selected patients when used as an adjunct to exercise.

Braces are not required for everyone and should not replace rehabilitation.

Foot Orthoses

Prefabricated foot orthoses may be useful as part of treatment for selected patients, particularly where an immediate symptomatic benefit is identified.

Custom foot orthoses are not required for every person with patellofemoral pain.

Which Exercises Are Used?

Current evidence supports knee-focused and hip-focused exercise as core components of treatment.

An individual programme may include:

  • Quadriceps strengthening
  • Hip abductor and extensor strengthening
  • Hip external-rotator strengthening
  • Controlled squat and step exercises
  • Single-leg movement control
  • Balance and neuromuscular training
  • Mobility or flexibility work when indicated

The appropriate exercises and loading level vary between patients. Rehabilitation aims to progressively improve the capacity of the joint and muscles while keeping symptoms at an acceptable level.

Treatment is not simply about isolating the “inner quadriceps”. Contemporary rehabilitation commonly combines knee strengthening, hip strengthening, education and appropriate management of physical load.

When Can You Return to Running?

There is no universal fixed return-to-running period.

Factors considered include:

  • Symptoms during daily activities being controlled
  • Ability to tolerate stairs and squatting
  • Improved knee and hip capacity
  • Acceptable symptoms while running
  • No substantial prolonged flare after activity

Running distance, speed, hills and overall weekly load should be increased gradually.

Gait retraining, including changes in running cadence, may be useful for selected runners and should be individualised.

Is Surgery Required?

Most people with patellofemoral pain do not require surgery.

Surgery may be considered in selected situations involving:

  • A significant focal cartilage or osteochondral defect
  • Recurrent patellar dislocation or instability
  • Important structural patellofemoral abnormalities
  • Persistent selected problems despite appropriate non-operative management

The surgical procedure depends on the underlying problem. Cartilage-restoration procedures, instability surgery and bony realignment procedures have different indications.

An MRI report of “chondromalacia” alone is not an indication for surgery.

When Should You See a Doctor?

Assessment is appropriate when:

  • Anterior knee pain continues for several weeks
  • Pain prevents running or sport
  • Stair climbing or squatting becomes difficult
  • Symptoms fail to improve despite appropriate activity modification
  • There is recurrent patellar dislocation or giving-way

Rapid major swelling after trauma, inability to bear weight, true locking, obvious deformity, joint redness and warmth or fever requires more urgent medical assessment.

Have Your Anterior Knee Pain Assessed

Pain around the kneecap during running, stair use or squatting can be assessed together with patellofemoral function and other knee structures.

Frequently Asked Questions

Are chondromalacia patella and runner's knee the same condition?
Not exactly. Chondromalacia patella describes structural change in the articular cartilage behind the kneecap. Patellofemoral pain, often called runner's knee, is a clinical pain syndrome felt around or behind the kneecap. Patellofemoral pain can occur without cartilage damage.
Can chondromalacia patella be seen on MRI?
MRI can be used to assess structural changes in patellar cartilage. However, MRI is not required for every patient with typical patellofemoral pain, and the degree of cartilage change on MRI does not always correspond to the severity of pain.
What does grade 4 chondromalacia patella mean?
In the classic Outerbridge classification, grade IV means advanced structural cartilage loss with exposure of the underlying subchondral bone. The grade does not by itself indicate the severity of pain, and treatment decisions should not be based on the grade alone.
Do you have to stop running completely with runner's knee?
Not always. Running load that significantly aggravates pain may be temporarily reduced and then progressively increased according to tolerance. The goal is usually to balance activity load with joint and muscle capacity rather than prescribe prolonged complete rest.
Which muscles are strengthened for patellofemoral pain?
Rehabilitation commonly includes quadriceps strengthening together with hip abductor, extensor and external-rotator strengthening. The exercise programme should be adapted to the person's strength, movement control, activity level and symptoms.
Does knee cracking mean the cartilage is worn away?
No. Cracking or crepitus does not by itself mean that there is advanced cartilage damage. Painless joint sounds can occur in healthy people. Assessment may be appropriate when the sounds are accompanied by pain, swelling, loss of movement or impaired function.
Is chondromalacia patella treated with surgery?
Most patients do not require surgery. Surgery may be considered for a significant focal cartilage or osteochondral lesion, recurrent patellar instability, important structural abnormality or selected persistent problems despite appropriate non-operative management.
Can patellofemoral pain completely improve?
Many people achieve substantial improvement in pain and function with appropriate exercise, management of physical load and individualised rehabilitation. Patellofemoral pain can nevertheless recur or persist in some people, so treatment should also address long-term muscle and activity capacity rather than short-term pain relief alone.
Academic Hospital note: MRI findings alone should not determine treatment for patellofemoral pain or chondromalacia patella. Symptoms, clinical examination, muscular capacity, movement control, activity load and any structural cartilage lesion should be assessed together. You can book an appointment.

References

  1. Academic Hospital. Kondromalazi Patella (Koşucu Dizi) Nedir? Belirtileri, Nedenleri ve Tedavi Yöntemleri
  2. Neal BS, et al. Best Practice Guide for Patellofemoral Pain Based on Synthesis of a Systematic Review, the Patient Voice and Expert Clinical Reasoning. British Journal of Sports Medicine, 2024.
  3. Willy RW, et al. Patellofemoral Pain: Clinical Practice Guidelines. Journal of Orthopaedic & Sports Physical Therapy.
  4. Ophey M, et al. Dutch Multidisciplinary Guideline on Anterior Knee Pain.
  5. Collins NJ, et al. Consensus Statement on Exercise Therapy and Physical Interventions for Patellofemoral Pain.
  6. van der Heijden RA, et al. Patellofemoral Cartilage Findings in Patients With Patellofemoral Pain.