A computer generated image of inside the knee joint.

Knee pain is a huge issue worldwide, affecting individuals of all ages and activity levels.

The reality is that knee pain happens for so many different reasons, usually from things like injuries, degenerative conditions (arthritis), or simply overexertion and overuse if you’re on your feet all day, every day.

Yet understanding knee pain’s root cause and symptoms is vital for effective management and recovery. 

This article delves deep into the common causes of knee pain, exploring its various symptoms, discussing preventive measures, and outlining treatment options.

Read on!

Pain When Flexing Knee: Common Causes

Some of the most common causes of knee pain include:

Sprains and strains: Sprains and strains are injuries to the soft tissues that make up the knee joint. Sprains occur when ligaments are overstretched, while strains involve actual damage to the tendons in some form or another. These injuries result from a sudden twisting action or forceful knee movement, often during sports or accidents.

Arthritis: Arthritis is a degenerative condition that occurs due to the wear and tear of cartilage that cushions the knees. Rheumatoid arthritis is different, being an autoimmune disease, yet it also affects the knee joint, causing inflammation and damage to the joint lining.

Meniscus Tears: The meniscus is a C-shaped piece of cartilage that acts as a shock absorber in the knee. Meniscus tears occur during knee injuries, often sudden twisting or pivoting movements, commonly seen in sports such as basketball or football. 

Ligament tears: The ligaments in the knee are what keep the bones in place and help the joint move freely without impedance. Ligament injuries of any sort would hamper the natural knee mobility and cause severe pain to the individual. The most commonly seen tear is an ACL tear.

Tendonitis: Tendonitis is inflammation of the tendons, which are thick bands of tissue that connect muscles to bones. Patellar tendonitis, also known as ‘jumper’s knee,’ affects the tendon connecting the kneecap to the shinbone. Tendonitis is often caused by repetitive stress, such as excessive jumping or running.

Fractures: Fractures are breaks in the bones that form the knee joint. While knee fractures can occur at any age, they’re far more common in mature adults due to weakened bones. Fractures result from falls, accidents, sports injuries, or direct trauma to the knee, such as a car or bike accident. 

Baker’s cyst: A Baker’s cyst is simply a fluid-filled sac in the back of the knee that often causes pain if it becomes too enlarged. 

Symptoms Of Knee Pain

The symptoms of knee pain differ depending on the cause of the pain (and the individual’s pain threshold.)

These are some of the more common symptoms:

  • Pain when bending or straightening the knee
  • Swelling and stiffness
  • Tenderness or warmth to touch
  • Popping or clicking sounds when moving the knee
  • Difficulty walking or bearing weight on the affected knee
  • Locking or catching of the knee
  • Instability or giving way of the knee
  • Weakness in the knee
  • Pain that radiates to the hip, thigh, or calf
  • Fever
  • Chills
  • Weight loss
  • Difficulties carrying out daily activities

If you experience any of these symptoms, it’s important to see your doctor to determine the cause of knee pain and get the right treatment underway. 

A man holding his injured knee while sitting on the ground.

Preventing Knee Pain

Below are tips to help you prevent knee pain.

Note: If you’re suffering right now from knee pain when flexing the knee, these tips might help relieve the intensity of the pain. 

Maintaining a healthy body weight: Painful but true! An active lifestyle is the answer to many knee problems; after all, extra weight puts added stress on the knees, increasing the risk of pain and degenerative conditions. Aim to maintain a healthy weight for your height and age. 

Engaging in low-impact exercise: Exercise helps strengthen the muscles around the knee joint and improve flexibility, which in turn helps prevent knee pain. Low-impact exercises like swimming, cycling, and walking are less likely to put stress on the knees than high-impact exercises on hard surfaces, such as running and jumping. Also, take care when going about your everyday activities, as even something insignificant, like walking up steps, can agitate the knees if an underlying problem exists. 

Strengthening the muscles around the knee joint: Strong muscles around the knee joint help to support the knee and, therefore, reduce the risk of pain. This includes strengthening the calf muscles, the hamstring muscles, and the quadriceps muscles. 

Wearing proper footwear: Wearing shoes that fit well and provide suitable support helps reduce knee stress significantly. Avoid wearing shoes with high heels or that are too tight.

Avoid prolonged standing: Prolonged standing puts extra stress on the knees. Try and sit down more often if you can. Saying that – too much sitting is also bad for your knees, so try and find the right balance for your body. Stretching exercises and getting up and walking about every 30 minutes is a good idea if you work in the office at a desk. 

By following these tips, you’ll help reduce knee pain risk and keep your knees healthy and strong.

A man holding his knee.

Treatment Options

Treatment of knee pain depends on the underlying cause and is something to be discussed with your primary healthcare provider. You’ll most likely have a physical examination with a doctor, orthopedic surgeon, or other knee specialist before having imaging tests to diagnose the issue first. 

Once a diagnosis is made, treatments may range from:

  • Rest, ice packs, compression, and elevation (RICE)
  • Over-the-counter pain medications
  • Seeing a physical therapist
  • Corticosteroid injections 
  • Surgery – but this is usually a last resort. 

Rest, ice, compression, and elevation (RICE) is a simple and effective way to reduce pain and swelling in the knee if the knee pain is manageable at home. 

Over-the-counter pain medications, such as ibuprofen and acetaminophen, can also help to relieve pain. 

Physical therapy helps strengthen the muscles around the knee joint and improve flexibility, reducing pain and even preventing future injuries. 

Corticosteroid injections can help to reduce inflammation in the knee. Surgery may be necessary in severe cases of knee pain, such as when there is a torn ligament or cartilage damage.

Your doctor will recommend the best treatment option for you based on the severity of your pain, the underlying cause, and your individual needs. 

If you are experiencing knee pain, seeing a doctor is important to get a true diagnosis and treatment plan. 

Early diagnosis and treatment help prevent further damage to the knee and improve your overall quality of life.

In most cases, joint pain tends to be an ongoing issue, whereas muscle pain should ease off after a few days. 

If you’re ever uncertain of the cause of your knee pain, be sure to see your healthcare provider for an accurate diagnosis and treatment plan.  

What are the red flags for knee pain?

If you experience any of these symptoms, be sure to get medical attention quickly:

  • Sudden knee pain with no apparent cause
  • Knee pain that gets worse, not better
  • Knee pain you’ve had for a long time
  • Sudden swelling or heat in the knee
  • Inability to stand on the affected knee
  • A known knee trauma


I hope you’ve found this post informative to better understand knee pain when flexing the knee. 

It can be a confusing time, but rest assured, with the right medical support and treatment, you’ll return to your best self quickly and with minimal stress.

For more reading to learn about knee health, click here

About the Author

Hi there! I’m Dr. Keagen Hadley, OTD, OTR/L. Straight out of the University of Mary, I’m all about blending my know-how in knee health, well-being, and medical technology. As a licensed occupational therapy doc, I’m here to translate complex concepts into clear, actionable insights – whether it’s knee care or groundbreaking healthcare tech.

Similar Posts