Knee pain is common amongst people of all ages. The complex knee joint enables daily tasks, such as walking, running, squatting, and jumping. It is highly vulnerable to injury, wear or even diseases as it carries the weight of the body and undergoes repetitive movement.
The Arthritis Foundation estimates that approximately 25% of adults all over the world experience knee pain. Knee pain is more likely to increase with age, obesity and certain lifestyle habits. Some individuals experience chronic knee pain that makes them walk with a lot of difficulty; others experience mild knee pain that disappears soon.
The good news is that most knee pain causes are identifiable and treatable. Understanding the underlying reasons behind the discomfort can help in selecting the right treatment and preventing future issues. In this guide, we will explore:
- How the knee works
- Common causes of knee pain
- Risk factors
- Symptoms to look out for
- Diagnosis and treatment
- Prevention strategies
- Expert answers to frequently asked questions
How is the Knee Joint Structured?
To understand why knee pain occurs, it’s essential to know how the knee joint is built.
Bones
The knee joint connects the femur (thigh bone) to the tibia (shin bone) and also involves the patella (kneecap). These bones provide the framework for movement.
Cartilage
Cartilage acts like a cushion between bones, absorbing shocks during walking, running, or jumping. The two main types in the knee are:
- Articular cartilage – covers the ends of bones.
- Meniscus cartilage – acts as a shock absorber between the femur and tibia.
Ligaments
These strong bands of tissue connect bones to each other and stabilize the joint:
- Anterior Cruciate Ligament (ACL) – controls forward movement of the tibia.
- Posterior Cruciate Ligament (PCL) – controls backward movement.
- Medial Collateral Ligament (MCL) – stabilizes the inner knee.
- Lateral Collateral Ligament (LCL) – stabilizes the outer knee.
Tendons
Tendon connects the bones and the muscles. The quadriceps tendon connects the patella with the thigh muscles. The patellar tendon, on the other hand, connects the kneecap and tibia.
Why Is the Knee Vulnerable?
The knee being a hinge joint, it has a forward and backward motion. It is highly susceptible to injury since it is unable to withstand twisting as happens during sports or abrupt movements. Knee is also prone to damages in the long-term since it carries weight.
What are the Common Causes of Knee Joint Pain?
Knee pain can have different causes, which can be broadly classified into injuries, medical conditions, overuse, degenerative changes, and systemic issues.
1. Injuries
- Ligament Injuries: A sudden twist, fall, or sports impact can damage the ACL, MCL, PCL, or LCL. ACL tears are particularly common among athletes in football, basketball, and skiing. Symptoms include a popping sound, immediate swelling, and instability.
- Meniscus Tears: The meniscus is a wedge-shaped cartilage that acts as a shock absorber. It can tear due to sudden twisting motions or heavy lifting. Tears cause pain, swelling, and sometimes locking of the joint.
- Tendon Injuries: Overuse can lead to tendon inflammation (tendinitis). Patellar tendinitis (jumper’s knee) is common among athletes who do frequent jumping.
- Fractures: Direct trauma, such as car accidents or falls, can fracture the patella or other bones in the knee joint. These injuries usually require urgent medical attention.
2. Medical Conditions
- Osteoarthritis: This degenerative disease occurs when cartilage wears down over time. It leads to stiffness, swelling, and gradual loss of mobility. It’s most common in people over 50.
- Rheumatoid Arthritis: An autoimmune condition that attacks the lining of joints, causing inflammation, swelling, and pain in both knees.
- Gout: Excess uric acid in the blood can form crystals in the knee joint, causing sudden, intense pain and redness.
- Bursitis: The bursae are small fluid-filled sacs that reduce friction in joints. Repeated kneeling or overuse can inflame these sacs, leading to bursitis.
- Patellofemoral Pain Syndrome: Often referred to as “runner’s knee,” this condition causes pain at the front of the knee due to muscle imbalance or misalignment of the kneecap.
3. Overuse and Repetitive Stress
Athletes, laborers, and people with physically demanding jobs can develop knee pain from repetitive movements. Overuse can lead to tendinitis, cartilage wear, and ligament strain.
4. Age-Related Degeneration
As we age, cartilage thins and loses its ability to cushion the joint. The synovial fluid that lubricates the knee also decreases, increasing friction and pain.
5. Inflammatory and Systemic Causes
- Lupus: This autoimmune disease can cause inflammation in multiple joints, including the knees.
- Infections (Septic Arthritis): When bacteria infect the knee joint, it causes severe swelling, redness, fever, and intense pain. Immediate treatment is crucial.
What are the Risk Factors for Knee Pain?
- Age: Higher risk of osteoarthritis and degeneration after age 50.
- Sports: High-impact sports increase the risk of ligament and meniscus injuries.
- Excess Weight: Each extra kilogram of body weight adds extra pressure on the knees.
- Past Injuries: Weakened joints from previous trauma are more vulnerable.
- Poor Footwear: Shoes without proper cushioning or arch support can cause misalignment and knee stress.
Which Symptoms Indicate the Cause of Knee Pain?
- Pain location: Inner knee pain may indicate MCL injury, while outer knee pain could be linked to LCL problems.
- Pain type: Sharp pain may indicate injury; dull aches may signal arthritis.
- Swelling: Immediate swelling after injury often means ligament damage.
- Instability: A “giving way” feeling suggests ligament injury.
- Locking: Difficulty straightening the knee can indicate a meniscus tear.
When to See a Doctor?
Seek medical help if you experience:
- Sudden, severe knee pain
- Swelling that appears immediately after injury
- Inability to bear weight on the affected leg
- Knee deformity
- Signs of infection like redness, warmth, or fever
What are the Diagnosis Alternatives for Knee Pain?
- Physical Examination: Checking range of motion, swelling, and stability.
- Imaging Tests:
- X-rays for bone fractures and arthritis
- MRI for ligament and cartilage damage
- Ultrasound for soft tissue injuries
- Lab Tests: Joint fluid analysis for infections or gout; blood tests for autoimmune conditions.
What are the Potential Treatments Based on Cause?
- Medications: NSAIDs, corticosteroids, or uric acid-lowering drugs for gout.
- Physical Therapy: Strengthening muscles, improving flexibility, and correcting movement patterns.
- RICE Method: Rest, Ice, Compression, Elevation for acute injuries.
- Surgery: ACL reconstruction, meniscus repair, or knee replacement in severe cases.
- Lifestyle Changes: Weight loss, low-impact exercise, and supportive footwear with insoles or heel pads.
How to Prevent Knee Joint Pain?
- Maintain a healthy weight.
- Warm up before workouts and cool down afterward.
- Use correct sports techniques.
- Strengthen muscles around the knee (quads, hamstrings, calves).
- Wear shoes with good cushioning and arch support.
Conclusion
Knee pain can result from many causes; it can start from acute injuries to chronic conditions like arthritis. Identifying the cause is essential for targeted treatment and long-term relief. By adopting healthy habits, avoiding overuse, and seeking prompt medical advice, you can protect your knees and maintain mobility well into old age.
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Frequently Asked Questions:
1. Which is the most common cause of knee pain?
Osteoarthritis is the most common cause of knee pain in the elderly. It happens due to progressive degeneration of cartilage. Sports injuries such as knee tears and torn ACLs are more frequent among the younger population.
2. What should I do if my knee pain is severe?
If your knee pain is severe and swelling occurs, your knees are not able to support your weight. You experience an apparent disability, or you have symptoms of infection such as fever and redness. In such cases, you must contact a physician immediately.
3. Can exercise worsen knee pain?
High-impact exercises like running on hard surfaces can aggravate knee pain, especially if there’s an existing injury. However, low-impact exercises like swimming, cycling, and walking can strengthen knee-supporting muscles and improve mobility.
4. Can obesity cause knee pain?
Yes. Extra weight increases the load on knee joints, accelerating cartilage breakdown and increasing the risk of arthritis. Even losing 5–10% of body weight can significantly reduce knee pain in overweight individuals.
5. What is the best way to prevent knee pain?
Prevention involves a combination of maintaining a healthy weight, strengthening leg muscles, using proper sports techniques, and wearing supportive footwear. Stretching before and after exercise also helps keep joints flexible.
References
- Arthritis Foundation. (2023). 10 Tips for Healthy Knees and Strong Joints as You Age. Retrieved from: https://www.arthritis.org/health-wellness/healthy-living/managing-pain/joint-protection/tips-for-healthy-knees [Viewed on 9 Sept 2025]
- Mayo Clinic. (2023). Knee pain – Symptoms and causes. Retrieved from: https://www.mayoclinic.org/diseases-conditions/knee-pain/symptoms-causes/syc-20350849 [Viewed on 9 Sept 2025]
- American Academy of Orthopaedic Surgeons. (2023). Knee Conditioning Program – OrthoInfo. Retrieved from: https://orthoinfo.aaos.org/globalassets/pdfs/2023-rehab_knee.pdf [Viewed on 9 Sept 2025]
- Duong, V., Oo, W. M., Ding, C., Culvenor, A. G., & Hunter, D. J. (2023). Evaluation and treatment of knee pain: a review. Jama, 330(16), 1568-1580. DOI: 10.1001/jama.2023.19675
- Johns Hopkins Medicine. (2023). Knee Pain and Problems. Retrieved from: https://johnshopkinshealthcare.staywellsolutionsonline.com/Library/DiseasesConditions/Adult/Skin/85,P00923 [Viewed on 9 Sept 2025]
