Knee pain: causes, prevention, treatment, best exercises

The knee is the largest joint in your body. It’s involved in everything from walking to going up and down stairs to squatting to pick an object up from the ground. You rely on your knees for many everyday activities, which is part of the reason knee pain is so common. But just because knee pain is common doesn't mean you have to live with it. There's a lot you can do to prevent and reduce knee pain, especially with exercise and movement.

Here, learn more about what causes knee pain, and how to prevent and treat it — especially with exercises from our Hinge Health physical therapists.

What is knee pain? 

Knee pain is a general term for pain that occurs in or around the knee. The knee is a hinge joint. It allows for back-and-forth movement of your lower leg, but minimal side-to-side movement. It’s made up of different structures — cartilage, menisci, ligaments, muscles, tendons, and more — that connects your femur (thigh bone) to your tibia (shin bone). These structures work together to give your knee the strength and stability needed for you to move. 

Although your knees are inherently strong and resilient, certain motions and medical conditions can result in pain or injury. Knee pain can strike suddenly after an injury, fall, or accident, or it can develop slowly and get worse over time. It can be acute (lasting less than 12 weeks) or chronic (lasting longer than 12 weeks).

Knee pain symptoms

The intensity of knee pain can range from a dull ache to shooting pain that affects weight-bearing abilities. Other signs and symptoms that may accompany knee pain include: 

• Swelling and stiffness 

• Redness 

• Warmth 

• Weakness or instability 

• Popping, cracking, or crunching noises 

• Inability to fully straighten the knee 

Knee Pain: a Hinge Health perspective 

Moving through knee pain can be scary, and it's understandable to want to avoid any activities that may cause discomfort. Know this: Movement is medicine when it comes to knee pain. Inactivity can actually make the pain worse over time as muscles weaken and the joint stiffens. By taking an active approach to managing your knee pain, you can improve your overall health, prevent future pain flares, and get back to doing what you love. And no matter what might be causing your knee pain (which we’ll discuss below), you're in the right place to get support for dealing with it.

Causes of knee pain  

Knee pain can be caused by injuries, mechanical problems, and diseases or conditions. Anyone can develop knee pain, but certain risk factors increase your chance of developing chronic knee pain. For instance:  

• Lack of strength and flexibility can increase the risk of knee injury. Strong muscles help stabilize and protect your joints. Muscle flexibility can help you achieve full range of motion.

• Certain sports, activities, and occupations tend to put more stress on the knees. These can include downhill skiing, basketball, and other sports that involve jumping and pivoting and running. Occupations include farming and construction work.  

• Previous knee injuries may increase your chances of re-injury. 

• Excess body weight can put extra stress on the joints in your lower body. This can contribute to pain during activities like walking and using the stairs. 

Here are other common reasons you may experience knee pain.

Injuries. Injury to any of the structures in or around the knee — ligaments, tendons, bursae, bones, cartilage — can cause pain. The most common injuries include: 

• Tendon injuries (also known as strains). Tendons are strong bands of connective tissue that connect muscles to bones. Tendon injuries can occur suddenly from activities such as skiing or tennis. They can also be due to an accident or overuse, causing your knee to become swollen and painful. 

• Ligament injuries (also known as sprains). Ligaments connect bones to one another. Each knee has four primary ligaments that connect your thigh bone to your shin bone — the anterior cruciate ligament (ACL), posteriorcruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL). An anterior cruciate ligament (ACL) injury is a very common cause of knee problems, but any ligament can be stretched or torn, resulting in knee swelling, instability, and pain. 

• Fractures. The bones in your knee — femur (thigh bone), tibia (shin bone), and patella (kneecap) — can break for a number of reasons, most commonly a fall, car accident, or osteoporosis. 

• Torn cartilage. Cartilage injuries most often involve the meniscus — a tough, rubbery piece of cartilage that acts as a shock absorber between your shinbone and thigh bone. Each knee has two menisci. Twisting your knee while bearing weight on it may cause a meniscus tear. 

• Dislocated kneecap. This occurs when the patella (kneecap) slips out of place. Dislocations can occur as a result of direct trauma to the knee and can be associated with anatomic abnormalities.

Bursitis. Bursae are small sacs of fluid that cushion different parts of your knee. They reduce friction and allow tendons and ligaments to glide smoothly over the knee joint. If any of the bursae in your knee become inflamed, it can cause discomfort and stiffness. 

Patellar tendinitis. The patellar tendon runs from the kneecap to the shinbone. If the patellar tendon gets injured it can become inflamed, resulting in patellar tendinitis. This is common in runners, skiers, cyclists, and those who do jumping activities (patellar tendinitis is sometimes referred to as jumper’s knee). 

Iliotibial (IT) band syndrome. This is a condition where the IT band — a tough band of tissue that extends from the outside of your hip to the outside of your knee — becomes tight and rubs against the outer portion of your thigh bone. Distance runners and cyclists are especially prone to hip and knee pain related to IT band syndrome.

Arthritis. There are more than 100 types of arthritis, but some commonly associated with knee pain include: 

• Osteoarthritis (OA) is characterized by changes in the cartilage at the ends of your bones. Over time, this can cause bones to sit closer together and sometimes rub against one another during movement. It doesn’t always cause symptoms, but it can contribute to stiffness, pain, and reduced range of motion for some people. 

• Rheumatoid arthritis (RA) is an autoimmune disease that causes your immune system to attack your joints. RA can affect many joints in the body and often first affects the small joints in the hands and feet. Over time, it can impact knees, sometimes causing pain, swelling, inflammation, and loss of function. 

• Gout is characterized by a buildup of uric acid in joints. It often first affects the big toe, but it can affect your other joints, including the knee. Gout can cause sudden, severe pain flares that last for several hours to weeks at a time. 

Hip or foot pain. Hip or foot pain — which affects how you walk — can put extra stress on your knees and cause pain. 

Patellofemoral pain syndrome. This is a general term for pain between the kneecap and the thighbone. Most people experience pain behind or around the kneecap during specific activities, such as going up stairs, running, squatting, or cycling. It's common in athletes and older adults who usually develop the condition secondary to arthritis.

Osgood-Schlatter's disease. This is a condition where the bony protrusion below the knee becomes painful and swollen, sometimes from repetitive extension (usually during exercise). It can affect children and young adults.

Loose body. Sometimes, an injury or certain conditions can cause a piece of bone or cartilage to break off in the joint space. This is typically harmless, but in rare cases it can interfere with knee movement and cause pain. 

When to see a doctor 

Given the complex nature of knee pain, many people wonder, “How do I know if my knee pain is serious?”

“While knee pain can definitely be uncomfortable and even scary, almost all types of knee pain can initially be managed with non-invasive treatments,” says Jonathan Lee, MD, orthopedic surgeon and senior expert physician at Hinge Health. “Treatments like injections and surgery are typically reserved for people who have persistent symptoms after first trying non-invasive choices, such as exercise therapy.”   

In rare cases, knee pain may indicate a more serious problem. See a doctor for knee pain if: 

• You’re unable to bear weight on your knee 

• You have severe pain after an accident or injury 

• Your pain doesn’t get better after a few weeks

• You can’t move or extend your knee

• Your knee “gives out” or feels unstable

• You have notable swelling in your knee

• You have an obvious deformity in your leg or knee

• Pain is accompanied by fever, redness, and swelling

• Pain is accompanied by knee locking, giving out, or clicking (clicking usually is not cause for concern in the absence of pain) 

Prevention tips

It’s not always possible to prevent knee pain. In fact, most people experience knee pain at some point in their life. Simple changes to your daily habits may help you prevent some cases of knee pain, though — especially chronic knee pain. 

• Stretch, especially before and after exercise. This lengthens the muscles in and around your knees to prevent injury and help your muscles work together more effectively.

• Wear supportive shoes. Flat shoes with good support help with shock absorption in your joints. If you have flat feet, try shoe inserts and arch supports (orthotics). 

• Build strength. Lack of muscle strength is one of the leading causes of knee injuries. Targeting your quadriceps (front of thighs) and hamstrings (back of thighs) will help support your knees. 

• Move often. As Hinge Health physical therapists say, movement is medicine. It’s important to move your joints through a wide range of motion. This stabilizes and strengthens the muscles in and around your knees, which helps prevent pain and stiffness.

• Switch it up. If you are prone to knee injuries or have chronic knee pain or arthritis, it may help to incorporate non-weight-bearing activities (like swimming and biking) into your cardio exercise routine. This challenges different muscles and cardiovascular endurance while giving your knees a break.

• Take care when running:

  • Avoid running straight down hills, especially steep ones. Walk down instead.

  • Avoid hard surfaces like cement. Try to run on a smooth, soft surface, such as a track. 

  • Check your shoes. Your running shoes should fit you well and have adequate cushioning. Hinge Health experts suggest changing shoes every 350 to 500 miles. This is when running shoes tend to lose their cushioning, which puts extra stress on joints. 

• Maintain a healthy weight for you. With each step you take, your knees absorb the equivalent of 1.5 times your body weight. That means that a 200-pound person puts 300 pounds of stress on their knees when they walk on a flat surface. And this is even higher when walking on an incline. While this can sound scary, it’s actually a good reminder of how strong and resilient your knees are — they’re designed to handle load. When knee pain is persistent, though, losing even a small amount of weight can have a big impact on knee pain relief.

• Do exercise therapy. Targeted movements, exercises, and stretches increase the strength and flexibility of the structures in and around your knees. (More information on this below).

Treatment for knee pain 

The following tips from our Hinge Health physical therapists and medical doctors can provide relief for most cases of mild to moderate knee pain.

• Ice and heat. Icing reduces swelling and inflammation and can help with acute and chronic knee pain. Heating increases blood flow and can reduce stiffness. You can apply either heat or ice as needed for 20 minutes at a time, but avoid using heat to treat a new injury as this can delay healing. 

• Compression and elevation. To manage swelling, you can use a brace or wrap around your knee and elevate your leg so your foot is above your heart.  

• Over-the-counter (OTC) medication. Pain relievers, such as ibuprofen (Advil, Motrin), naproxen (Aleve), and acetaminophen (Tylenol), can be helpful for knee pain. It’s important to make sure that you are safely able to take these medications, based on your medical history.

• Topical pain relievers. These products come in creams, salves, ointments, and patches. They deliver pain-relieving substances (usually ibuprofen, menthol, or lidocaine) through your skin. 

• Steroid injections. If over-the-counter medication does not offer sufficient pain relief, your doctor may suggest cortisone steroid injections to help counter pain and inflammation. The effects of an injection vary and can last from a few weeks to a few months. 

• Complementary therapies. Massage, biofeedback, relaxation, meditation, acupuncture, yoga, and visualization may provide knee pain relief. Talk to your doctor if you’re interested in trying any of these. 

While all of the above steps can help knee pain, one of the most effective is exercise therapy.

Low-impact exercises stretch, strengthen, and stabilize the structures that support your knee, which increases joint mobility while decreasing pain. The given exercises are recommended by Hinge Health physical therapists as a starting point. “I recommend doing these two to three times per week to see how your body reacts,” says Mary Kimbrough, PT, DPT, a physical therapist at Hinge Health.

“Gradually increase to doing them daily as tolerated. Let symptoms be your guide. Some discomfort is okay, but if pain increases or worsens, talk to your provider before going any further.” 

The information contained in these videos is intended to be used for educational purposes only and does not constitute medical advice or treatment for any specific condition. Hinge Health is not your healthcare provider and is not responsible for any injury sustained or exacerbated by your use of or participation in these exercises. Please consult with your healthcare provider with any questions you may have about your medical condition or treatment.

Surgery for knee pain

Knee surgery isn’t recommended as a first course of treatment for knee pain because most people can get knee pain relief from targeted exercise, stretching, and other conservative treatments. There are, however, some instances when surgery is advised. If knee pain causes you to change your daily activities or it takes a toll on your quality of life, your doctor may suggest surgery, such as knee arthroscopy or a total or partial knee replacement. 

Talk to your doctor about whether you’re a good candidate for surgery. 

How Hinge Health can help you

If you have joint or muscle pain that makes it hard to move, you can get the relief you’ve been looking for with Hinge Health’s online exercise therapy program.

The best part: You don’t have to leave your home because our program is digital. That means you can easily get the care you need through our app, when and where it works for you.

Through our program, you’ll have access to therapeutic exercises and stretches for your condition. Additionally, you’ll have a personal care team to guide, support, and tailor our program to you.

See if you qualify for Hinge Health and confirm free coverage through your employer or benefit plan here.

This article and its contents are provided for educational and informational purposes only and do not constitute medical advice or professional services specific to you or your medical condition.

References 

1. Bunt, C. W., Jonas, C. E., & Chang, J. G. (2018). Knee Pain in Adults and Adolescents: The Initial Evaluation. American Family Physician, 98(9), 576-585. 

2. Evans, J. & Nielson, J. l. Anterior Cruciate Ligament Knee Injuries. (2022) StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Retrieved from: https://www.ncbi.nlm.nih.gov/books/NBK499848/

3. Jones, B. Q., Covey, C. J., & Sineath, M. H. (2015). Nonsurgical Management of Knee Pain in Adults. American Family Physician, 92(10), 875-83.

4. Common Knee Injuries - OrthoInfo - American Academy of Orthopaedic Surgeons. (2014). Retrieved from https://orthoinfo.aaos.org/en/diseases--conditions/common-knee-injuries/