Quick version
What is Runner's Knee?
Runner's knee, or iliotibial band syndrome (ITBS), occurs when the long tendon running from the hip to the outside of the lower leg (IT band) becomes irritated. During repeated bending and straightening of the knee, the tendon slides over a bony prominence on the outside of the femur. If the load becomes too high, local inflammation or irritation occurs, leading to pain.
Unlike a cruciate ligament injury, runner's knee is not an acute injury caused by trauma, but a repetitive strain injury caused by monotonous movements.
Common Symptoms of Runner's Knee
Symptoms of runner's knee often come on gradually and are clearly linked to activity.
Symptoms during activity
- A sharp or burning pain on the outside of the knee.
- Pain often starts after a certain distance or time during a run.
- Pain worsens when running downhill or taking longer strides.
- Pain often disappears shortly after stopping, but returns during the next session.
Symptoms in daily life
- Stiffness on the outside of the thigh.
- Tenderness when pressing directly on the bony prominence on the outside of the knee.
- Pain when walking down stairs.
Why do you get Runner's Knee?
The primary cause is an increase in training volume that is too rapid, but several factors play a role:
- Overload: Running too far, too often, or too intensely without sufficient recovery.
- Weak gluteal muscles: If the muscles around the hip are weak, the knee may collapse inward, increasing tension in the IT band.
- Running gait and equipment: Old shoes or a running style that puts weight on the outside of the foot.
- Anatomy: People who are bow-legged (varus alignment) have naturally higher tension in the tendon.
When should you seek care?
Contact a healthcare provider or physiotherapist if:
- The pain prevents you from performing daily activities.
- Rest does not provide improvement after 1–2 weeks.
- You have swelling or redness on the outside of the knee that does not subside.
How to find out if you have Runner's Knee
A physiotherapist or doctor can usually diagnose the condition through a clinical examination and specific provocation tests (e.g., Noble's test).
If the diagnosis is uncertain, or if other injuries such as a meniscus tear or cruciate ligament injury are suspected, an MRI of the knee is the best tool. MRI provides a detailed image of soft tissues and can confirm if there is thickening of the IT band or fluid accumulation under the tendon.
