You’re walking through your day as usual climbing stairs, standing from your desk, or maybe just sitting comfortably when suddenly, your knee starts to ache.
No trip, no twist, no fall. Just pain.
If you’ve ever found yourself thinking, “How can my knee hurt when I haven’t injured it?”, you’re not alone. As a physiotherapist, I meet many patients who experience this exact situation, and it can be both confusing and worrying.
The good news? In many cases, the cause is something we can identify and treat effectively.
In this guide, we’ll explore some of the most common reasons behind sudden knee pain without injury and how physiotherapy can help you find relief.
1. Osteoarthritis
Osteoarthritis is a gradual wearing away of the smooth cartilage that cushions your knee joint. Imagine the cartilage as a soft protective padding between the bones over time, that padding can thin, causing the bones to rub more directly.
Symptoms:
- Stiffness (especially first thing in the morning or after sitting for a while)
- A dull, aching pain during movement
- A sensation of grinding or clicking in the knee
Who is at risk?
People over 50, anyone with a history of knee stress (sports, heavy labour), those carrying extra weight, or with a family history of arthritis.
How physiotherapy can help:
We focus on strengthening the muscles around your knee to take pressure off the joint, improving flexibility, and teaching you movement strategies that protect the knee in daily life.
2. Patellar Tendinitis (Jumper’s Knee)
The patellar tendon connects your kneecap to your shinbone. Patellar tendinitis happens when that tendon becomes irritated or inflamed often from repetitive stress, not a single traumatic event.
Symptoms:
- A dull ache just below the kneecap
- Pain when running, jumping, or going downstairs
- Stiffness after sitting with bent knees
Who is at risk?
Athletes in jumping sports, people who suddenly increase their activity level, and even active walkers or cyclists.
How physiotherapy can help:
We guide you through a tailored loading program to strengthen the tendon gradually, adjust your activity patterns, and correct any movement habits that might be overloading the knee.
3. Bursitis
Your knee has small, fluid-filled sacs called bursae that help reduce friction between tissues. Bursitis occurs when one of these sacs becomes inflamed.
Symptoms:
- Swelling and tenderness over the knee
- Warmth or redness in the area
- Pain when bending or putting pressure on the joint
Who is at risk?
People who kneel frequently (gardeners, tradespeople), those who repeat the same movements often, or who increase activity too quickly.
How physiotherapy can help:
We identify and modify the activities that aggravate your bursae, guide you through gentle mobility and strengthening work, and help prevent recurrence by improving movement patterns.
4. Baker’s Cyst
A Baker’s cyst is a fluid-filled swelling behind the knee, often forming when the joint produces extra fluid due to irritation.
Symptoms:
- A lump or fullness behind the knee
- Tightness when straightening or bending the leg
- Occasionally, discomfort radiating down the calf
Who is at risk?
Often linked to arthritis, meniscus irritation, or other chronic knee conditions.
How physiotherapy can help:
While we don’t “pop” the cyst itself, we address the underlying joint problem, reduce swelling, and restore healthy knee mechanics to prevent fluid buildup.
5. Referred Pain (from the Hip or Lower Back)
Sometimes, the pain you feel in your knee doesn’t actually start there. Nerve pathways can carry discomfort from your hip or lower back down to the knee.
Symptoms:
- Knee pain without local swelling or injury signs
- Accompanied by hip stiffness or lower back discomfort
- Pain that changes with back or hip movement
Who is at risk?
People with existing back or hip conditions, sedentary posture habits, or uneven walking mechanics.
How physiotherapy can help:
We assess your whole movement system—hips, spine, and knees—to find the true source of the pain, then treat it with targeted mobility, strengthening, and posture training.
When You Should See a Professional
While many causes of non-injury knee pain are manageable, certain symptoms require prompt attention.
Seek professional help immediately if you notice:
- Inability to bear weight on the leg
- A visible change in the knee’s shape
- Sudden or severe swelling
- Fever or redness with warmth around the joint
- Numbness or weakness in your leg
- Locking of the knee or inability to fully straighten or bend it
Final Thoughts
Sudden knee pain without an injury is more common than you might think. It doesn’t always mean something serious, but it’s important to find out why it’s happening so you can address the cause, not just the symptoms.
Physiotherapists are trained to assess, diagnose movement problems, and guide you toward safe, effective solutions. The sooner you get it checked, the sooner you can get back to moving confidently.
Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice. Always consult a healthcare provider for diagnosis and treatment tailored to you.
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References
- Bennell, K. L., Hinman, R. S., Metcalf, B. R., Buchbinder, R., McConnell, J., McColl, G., … & Forbes, A. (2005). Efficacy of physiotherapy management of knee joint osteoarthritis: a randomised, double blind, placebo controlled trial. Annals of the Rheumatic Diseases, 64(6), 906–912. https://pubmed.ncbi.nlm.nih.gov/15897310/
- Fransen, M., McConnell, S., Harmer, A. R., Van der Esch, M., Simic, M., & Bennell, K. L. (2015). Exercise for osteoarthritis of the knee: a Cochrane systematic review. Cochrane Database of Systematic Reviews, 1(1), CD004376. https://pubmed.ncbi.nlm.nih.gov/26405113/
- Cook, J. L., & Purdam, C. R. (2009). Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load‐induced tendinopathy. British Journal of Sports Medicine, 43(6), 409–416. https://pubmed.ncbi.nlm.nih.gov/18812414/
- Rio, E., Kidgell, D., Purdam, C., Gaida, J., Moseley, G. L., Pearce, A. J., & Cook, J. (2015). Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British Journal of Sports Medicine, 49(19), 1277–1283. https://bjsm.bmj.com/content/49/19/1277
- Speed, C. A. (2001). Therapeutic ultrasound in soft tissue lesions. Rheumatology, 40(12), 1331–1336. https://academic.oup.com/rheumatology/article-abstract/40/12/1331/1787872
- StatPearls. (2023). Bursitis. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK513340/
Amit Saraswat is the Founder of Physioveda Medical Center, a Dubai-based clinic focused on personalized physiotherapy and integrative healthcare. With a passion for patient-centric solutions, he leads the vision behind Physioveda’s evidence-based approach to pain relief and long-term recovery.