Pain around the kneecap can be difficult to interpret, especially when it develops gradually. Common runner’s knee symptoms include an ache at the front of the knee, discomfort on stairs, pain after sitting with the knee bent and symptoms that build as running or other loaded activity increases.
Runner’s knee is a common name for patellofemoral pain syndrome (PFPS). You do not need to be a runner to develop it. Because the pattern can overlap with tendon, meniscal, bursal and ligament problems, symptoms alone cannot confirm the diagnosis.
Who is this guide for?
This guide is for runners, walkers and anyone with front-of-knee pain who wants to understand whether their symptoms fit PFPS, what may trigger them and when an assessment may be sensible.
What is a runner's knee syndrome (patellofemoral pain syndrome)?
Patellofemoral pain is pain around or behind the patella, or kneecap. It is usually linked to activities that load the joint while the knee is bent, such as running, squatting, using stairs or prolonged sitting.
PFPS is mainly a clinical diagnosis based on your history and examination, after considering other causes of anterior knee pain. It is not usually a sign of one specific torn or damaged structure, and a scan is not required in every case.
What are the early signs of runner's knee?
The early signs often develop gradually. You may notice:
- A dull ache at the front of the knee, particularly during or after activity.
- Pain on stairs, during squatting or kneeling.
- Aching or stiffness after sitting with the knee bent.
- Grinding, clicking or crackling around the kneecap.
- Symptoms that return as running distance, pace or frequency increases.
Clicking or grinding does not automatically mean the joint is being damaged. True locking, marked swelling or genuine instability is less typical of straightforward PFPS and needs closer assessment.
Where exactly does runner's knee pain occur?
Pain is usually felt around, behind or sometimes just below the kneecap. It may feel broad and difficult to pinpoint rather than like one sharply tender spot. One or both knees can be affected, but location alone cannot distinguish PFPS from every other cause of knee pain.
What triggers runner's knee symptoms?
Symptoms often become noticeable after the load through the knee changes. This may follow a sudden increase in running distance, speed or frequency, a change in surface or footwear, or repeated squatting, kneeling and stair descent.
Hip and thigh strength, movement control and how load is distributed through the leg may also be relevant. There is no single cause for every patient, so assessment should focus on your own symptoms and activity pattern.
How is runner's knee different from jumper's knee (patellar tendinopathy)?
Runner’s knee vs jumper’s knee can be confusing because both cause front-of-knee pain. PFPS usually produces a broader ache around or behind the kneecap and is often aggravated by stairs, squatting, running and prolonged sitting.
Jumper’s knee, or patellar tendinopathy, tends to cause a more localised tender point in the patellar tendon just below the kneecap and is strongly associated with jumping and explosive loading. The two can overlap, so a physiotherapist assessment may be needed to identify the cause.
How is runner's knee different from other knee pain causes?
Several knee problems can resemble runner’s knee:
| Condition | Typical features |
|---|---|
| Meniscal tear | May follow a twisting injury and can cause catching or true locking. |
| Bursitis | Localised swelling and tenderness over an irritated bursa, a small fluid-filled cushioning sac. |
| Chondromalacia patellae | Cartilage changes under the kneecap; symptoms can overlap with PFPS. |
| Ligament injury | More often follows a clear injury and may cause instability or rapid swelling. |
This overlap is why a proper assessment can be useful. Imaging should be used selectively when it is likely to answer a specific clinical question.
When should you get runner's knee assessed?
Consider an assessment if pain lasts beyond a couple of weeks, keeps returning whenever you run, or affects stairs or everyday activity. Swelling, locking, catching, or genuine giving way are not typical features of uncomplicated PFPS and warrant closer assessment.
Seek urgent medical advice after a significant injury if you cannot move or bear weight through the knee, if it is severely swollen or deformed, or if it becomes hot and red with fever or if you feel unwell.
What does a runner's knee assessment involve at RAD Clinics?
When you come to us with possible runner’s knee symptoms, we review your history, activity level, training changes and symptom pattern. We then assess relevant movement, strength and how the kneecap moves during selected tasks, with clear explanations throughout.
PFPS is usually diagnosed clinically, so a scan is not automatically needed. Where appropriate, our musculoskeletal ultrasound can assess selected superficial soft tissues around the knee. It cannot assess every possible cause equally well, and another investigation or specialist review may be more suitable if deeper joint structures, bone or a meniscal injury are suspected.
We will explain the findings and discuss a practical next step, which may include physiotherapy and rehabilitation.
Key takeaways
- Runner’s knee, or PFPS, usually causes a gradual ache around or behind the kneecap.
- Stairs, squatting, prolonged sitting and increases in running load commonly provoke symptoms.
- Patellar tendinopathy tends to cause more focal tenderness below the kneecap.
- Marked swelling, true locking or genuine instability are not typical of straightforward PFPS.
- Diagnosis is mainly clinical; imaging may help when another condition or specific structure needs assessment.
- We can assess your symptoms and movement and use MSK ultrasound where appropriate.
Common Questions About runner's knee symptoms
Can runner's knee go away on its own?
Mild symptoms may settle when aggravating load is reduced, but PFPS can persist or recur. Evidence-based care commonly centres on education and appropriately progressed exercise rather than simply waiting for symptoms to disappear.
Is it normal for runner's knee to affect both knees?
Yes. Patellofemoral pain can affect one or both knees. Persistent symptoms still need to be interpreted in context rather than assumed to be PFPS.
Does runner's knee show up on an ultrasound scan?
There is no single ultrasound finding that proves PFPS. MSK ultrasound may help us assess selected superficial tissues or look for another explanation, such as patellar tendon or bursal changes, where relevant.
Can you keep exercising with runner's knee symptoms?
You may not need to stop all exercise, but repeatedly pushing through worsening pain is not advisable. Modifying activities that clearly provoke symptoms while maintaining comfortable activity may be appropriate. A qualified healthcare professional can guide your return to running.
References
- Neal BS, Lack SD, Bartholomew C, Morrissey D. Best practice guide for patellofemoral pain based on synthesis of a systematic review, the patient voice and expert clinical reasoning.
- Willy RW, Hoglund LT, Barton CJ, et al. Patellofemoral Pain: Clinical Practice Guidelines.
- American Academy of Family Physicians. Knee Pain in Adults and Adolescents: The Initial Evaluation.
