Reasons, Treatment, and When to Contact a Healthcare Provider

Knee pain can be a very common symptom. While this is frustrating and frustrating, the good news is that many of the causes of knee pain can often be treated.

Diagnosing knee pain first requires a detailed medical history detailing the pain, such as how it feels (such as pain, roughness, or burning), where it is (such as in front or behind the knee), when it started (such as gradually or sudden injury), and if there was a recent injury (such as a blow to the knee).

In addition to your medical history, your healthcare provider will examine your knee joint and possibly order imaging tests to make or confirm the diagnosis.

At the end of the day, understanding the exact cause of knee pain is key to developing an effective treatment plan for you and your healthcare provider, one that optimizes symptom relief and return to normal function.

Illustration by Alexandra Gordon, Get Meds Info


The knee is a complex structure made up of three bones: the lower femur, the upper tibia, and the patella.

In addition, there are strong ligaments and tendons that hold these bones together, as well as cartilage under the kneecap and between the bones to soften and stabilize the knee. Damage or disease affecting any of these structures can cause pain.


If you have knee pain, common causes include:

Knee arthritis

There are different types of arthritis that affect the knee joint, the two most common being osteoarthritis and rheumatoid arthritis.

  • Knee osteoarthritis develops as a result of "wear and tear" on the knee cartilage and is most common in people over 50 years of age. As the cartilage breaks down, pain develops, often gradually increasing from a sharp pain that intensifies with movement of the knee to a constant, dull ache.
  • Rheumatoid arthritis is an autoimmune disease in which a person's immune system attacks multiple joints in the body. In addition to pain, swelling, redness, and warmth may appear over the kneecap. Unlike osteoarthritis, knee pain in rheumatoid arthritis tends to decrease with physical activity.

Knee Ligament Injuries

Your knee has four main ligaments: two lateral ligaments and two cruciate ligaments.

Collateral Ligament Injury

The collateral ligaments (medial collateral and lateral collateral) are on the side of the knee and connect the femur (thigh) with the shin. Medial collateral ligament (MCL) injury is often the result of a direct blow to the outside of the knee causing pain inside the knee.

A blow to the inside of the knee can damage the lateral lateral ligament (LCL), causing pain on the outside of the knee.

Cruciate ligament injury

The cruciate ligaments (anterior cruciate and posterior cruciate) are divided within the knee joint, with the anterior cruciate ligament attached to the lower leg in front and the posterior cruciate ligament attached to the back.

Anterior cruciate ligament injuries are the most common type of knee injury, often the result of a direct impact or a sudden change in direction or speed while running. A clicking noise is usually heard, which is accompanied by sudden bloating and feeding. from the knee.

Posterior cruciate ligament injuries are rare and generally occur when a high-energy force is applied to the knee (such as a bent knee hitting the board in a car accident). In addition to pain in the back of the knee, typical symptoms associated with this ligament injury are swelling and instability of the knee.

Torn knee cartilage (meniscus)

Between the femur and the tibia are two rigid C-shaped cartilages (called menisci). A torn meniscus is a common cause of knee pain and can occur in young people (often during sports) or in older people, as cartilage weakens with age, making it more prone to breaking .

In addition to pain, a person with a torn meniscus may first hear a "pop" when a tear occurs. This is followed by a gradual development of stiffness and swelling of the knee, accompanied by clicking, locking, or grabbing of the knee.

Patellar tendonitis and tears

Patellar tendinitis is an inflammation of the patellar tendon, the large tendon that connects the patella to the top of the tibia. Patellar tendinitis is more common in people who play sports or other activities that require frequent running and jumping. People with this condition often describe a constant dull ache that is exacerbated by physical activity.

In some cases, the patellar tendon can become weak, making it more likely to rupture. A ruptured patellar tendon causes severe pain, swelling above the knee, and a tearing or popping sensation. Depending on the severity of the tear, a person may notice a dent at the bottom of the kneecap and have difficulty walking due to a knee prolapse.

Patellofemoral pain syndrome

Patellofemoral pain syndrome is more common in adolescents and young adults and is usually caused by vigorous activities that put pressure on the knee, such as running, squatting, or climbing stairs .

This condition causes a dull ache under the kneecap, sometimes called patellar chondromalacia , which means that the cartilage behind the kneecap has softened and started to wear away. The abnormal position of the knee can also cause or contribute to this condition.

In addition to pain that is aggravated by activities that require frequent bending of the knees or prolonged sitting (for example, when working at a desk), a person may hear knee clapping when standing up after sitting for a long time or when climbing stairs. Swelling and blockage of the knee are rare in this syndrome.

Baker's cyst

Baker's cyst swells at the back of the knee joint and is sometimes a sign of another underlying problem, such as a meniscus tear . While not all Baker's cysts are painful, if so, the "constricting" pain is felt in the back of the knee and is often associated with knee stiffness and a visible lump that worsens with knee. physical activity.

Prepatellar bursitis

Your prepatellar pouch (a fluid-filled pouch) is located just above the kneecap. Pre-patellar bursitis , when the bursa becomes inflamed, is most often caused by people who often kneel, such as gardeners or carpet makers .

Less commonly, an infection, gout, rheumatoid arthritis, or a direct blow to the knee can cause bursitis. In addition to mild pain in the knee, which can only be felt when the knee is moved or the affected area is touched, rapid swelling over the kneecap usually occurs.

Tibial band syndrome

Tibial ligament syndrome refers to inflammation of the tibial ligament, a thick collection of fibers that run along the outer thigh. Iliotibial tract inflammation is often the result of overuse, especially in runners, and causes pain and burning on the outside of the knee joint. Sometimes the pain spreads from hip to hip.

Less common

Here are some of the less common causes of knee pain:

Dislocated kneecap

A dislocated kneecap causes acute symptoms during a dislocation and is due to a sudden blow to the knee, such as a car accident or fall to the ground , or a twist that causes the kneecap to come off.

In addition to pain in the front of the knee , a person may notice a bend in the knee, a slip to the side, or a pinch during movement. Swelling, stiffness, and cracking in the knees are also common.


Gout is an inflammatory condition that occurs in people with high levels of uric acid in the bloodstream. These high levels of uric acid form crystals in certain joints, such as the big toe, toes, knee, or thigh.

A gout attack often affects one joint at a time, causing severe pain with burning and swelling, warmth, and redness of the affected area.

Plica syndrome

Plica syndrome is a rare cause of knee pain and occurs when the plica, the fetal remnant of the synovial capsule of the knee joint, becomes irritated .

People with crease syndrome often report pain in the middle and front knee that worsens with knee activity, such as squatting, running, kneeling, or sitting for prolonged periods. Bending the knee may feel a popping sensation.

Osgood-Schlatter disease

Osgood-Schlatter disease is a condition that affects children between the ages of 9 and 14. It usually occurs after a recent growth spurt, when irritation develops in the front of the knee joint, causing pain and sometimes swelling just below the kneecap. The pain decreases with rest and increases with knee activity, such as running and jumping.

Dissecting osteochondritis

Osteochondritis dissecantes (OCD) is another condition seen in children and adolescents and is the result of insufficient blood supply to a small segment of the knee bone. As a result, the affected bone and the cartilage that covers it weaken and sometimes fall off. of the underlying bone.

Pain that is poorly located in the knee, which is felt with physical activity, is the first symptom. Be aware that many conditions can have similar symptoms. As the condition progresses, there may be constant swelling and stiffness in the knees.

Knee infection

An infected knee joint causes severe knee pain, as well as swelling, warmth, painful movements, and often fever. In some cases, an infected joint is caused by a bacterial infection in the bloodstream .

Patella fracture

A patella fracture can occur if you fall directly onto your knee or if you hit the knee directly, such as hitting your knee on the dash in a car accident. In addition to severe pain and difficulty straightening the knee, bruising and swelling over the kneecap, sometimes with a visible deformity, are common.

Bone tumor

In very rare cases, knee pain can be caused by a bone tumor , such as osteosarcoma. Associated symptoms such as fever or involuntary weight loss may also occur, as well as pain that is especially worse at night.

When to contact a healthcare provider

If you are unsure of the cause of your symptoms or do not know the specific recommendations for treating your condition, you should seek medical attention. Treatment for knee pain should be directed at the specific cause of your problem.

Contact your healthcare professional if you have:

  • Inability to walk comfortably on the affected side.
  • Injury causing joint deformity.
  • Knee pain that occurs at night or while resting.
  • Knee pain that does not go away for several days.
  • Blockage (inability to bend) in the knee
  • Swelling of the joint or lower leg area.
  • Signs of infection, including fever, redness, or warmth.
  • Any other unusual symptoms


Many conditions of the knee joint can only be diagnosed by a healthcare professional based on medical history and physical examination.

History of the disease

When discussing knee pain with your healthcare provider, try to provide as much information as possible. This is because clues such as the exact location and time of the knee pain, as well as associated symptoms, can help your healthcare provider make a diagnosis.


Where you feel pain in your knee can provide some clues as to what type of injury or condition is causing your discomfort.

For example, pain on the medial or medial side of the knee (the side closest to the other knee) can be caused by medial meniscus tears , MCL injuries , and arthritis , while pain on the outside of the knee or on the side can be caused by lateral meniscus tears , LCL injuries, IT-range tendonitis, and arthritis.

Also, pain in the back of the knee can be caused by a Baker's cyst . Pain in the front of the knee is most commonly associated with the kneecap and can be caused by a number of different problems affecting the area, such as chondromalacia or prepatellar bursitis.


Just as the location of the knee pain can indicate the cause of the problem, the time of day the pain occurs and the actions that cause it can also provide information.

Pain when walking down stairs is most often associated with swelling under the kneecap. Knee pain after waking up in the morning, which resolves quickly with light physical activity, can sometimes be associated with early arthritis .

Associated symptoms

In addition to pain, your healthcare provider will also ask if you noticed swelling, experienced symptoms such as fever or chills (a sign of a possible infection), or other symptoms throughout your body (such as joint pain elsewhere, fatigue, or weight inexplicable). loss), which may indicate a systemic disorder such as rheumatoid arthritis.

Physical exam

In addition to a detailed medical history, a complete physical exam is important to make a correct diagnosis. When examining the affected knee, your healthcare professional will closely observe the knee for swelling and move it to assess stability, noise, and blockage.


Knee swelling is common in many knee problems. When an effusion (accumulation of excess fluid around the joint) occurs immediately after a knee injury, one possible cause is damage to the internal structure of the joint. When swelling develops gradually over the hours or days after the injury, it may be associated with less serious problems.

When swelling develops gradually over the hours or days after the injury, it may be associated with less serious problems. Edema that occurs without currently known trauma can be caused by osteoarthritis , gout , inflammatory arthritis , or a joint infection .

Range of motion

Several general conditions affect knee mobility. If mobility is gradually limited, the cause can often be related to arthritis . If mobility is limited after an acute injury , there may be swelling that limits movement, or sometimes a broken structure that limits movement.


Stability of the knee is provided by the ligaments that connect the lower leg (tibia) to the femur. When the ligaments are stretched or torn, the knee may feel as if it is sagging under the patient.

The feeling that the knee might bounce under you is a common symptom of ligament damage , although this feeling can also occur due to muscle swelling or weakness in the knee.


Knee pops and pops are common and often not a sign of any particular problem. When clapping is painless, this is usually not a problem , but painful clapping and popping should be evaluated by your healthcare professional. Clapping can be heard or felt during knee twisting when a ligament such as the ACL is damaged.

Grinding or cracking sounds are common symptoms of cartilage problems. If the cartilage wears away, as with chondromalacia , there is often a cracking sensation when you place your hand on the kneecap and bend the knee. A similar grinding sensation may be felt with knee arthritis .


Obstruction is a symptom that occurs when the patient is unable to bend or straighten the knee. Blockage can occur because something physically blocks the knee from moving or due to pain that prevents the knee from moving normally.

One way to determine if something is physically blocking your knee is to have a healthcare professional inject a pain reliever into your knee. After the medication has worked, you can try bending your knee to determine if pain is blocking movement or if there is a structure, such as a torn meniscus , that blocks normal movement.


When examining a doctor, it is important to undergo a comprehensive examination to make a diagnosis. This includes imaging studies.

In most cases, your healthcare provider will start with an X-ray, which not only shows bone, but may also show signs of soft tissue damage, arthritis, or alignment problems, and then perform an ultrasound or MRI . Magnetic if necessary to further assess soft tissue damage.

Differential diagnosis

While it may seem obvious that the knee is the cause of knee pain, this is not always the case. Sometimes a problem in the lower back, sacroiliac joint , or hip can indicate knee pain. Your healthcare provider will suspect the recommended source based on your physical exam.

For example, pain that is not in the knee area will not make the knee hurt when pressed. There will also be no knee swelling and your knee will have a normal range of motion.


Some common knee pain treatments are listed here (although they are not exhaustive), and not all are suitable for all conditions.

Self-service strategies

Many of the initial treatments for knee pain are simple, straightforward, and can be done at home.


The first treatment for the most common conditions that cause knee pain is to temporarily rest the joint so that the inflammation subsides immediately. Sometimes this is the only step necessary to relieve knee pain.


Aside from resting, applying a cold gel , an ice pack, or frozen vegetables to the knee is perhaps the most widely used treatment for knee pain. When applying ice to the knee, do not apply ice directly to the skin and ice only for 15-20 minute sessions (several times a day).


Depending on the diagnosis, your healthcare provider may recommend knee support to help relieve your pain. For example, if you have patellar tendonitis, your healthcare provider may recommend a support bandage and patellar tendon straps.

Occasionally, a knee brace may be recommended to maintain knee stability, such as in the case of a lateral ligament injury or partial knee dislocation. Also, for some types of fractures, a cast or splint may be applied to heal.


Physical therapy is an extremely important aspect of the treatment of almost all orthopedic conditions. Physical therapists use a variety of techniques to increase strength, restore mobility, and help patients stay active before injury.

The American Academy of Orthopedic Surgeons (AAOS) emphasizes the importance of participating in an exercise program (led by your PCP and physical therapist) after a knee injury or surgery. A knee training program offered by AAOS focuses on stretching and strengthening the muscles that support the knee, including the quadriceps, hamstrings, inner and outer thighs, and glutes.


Medications are often used not only to relieve pain but also to treat an underlying knee problem.


Nonsteroidal anti- inflammatory drugs , commonly called NSAIDs, are some of the most commonly prescribed medications, especially for patients with knee pain caused by problems like arthritis, bursitis, and tendonitis.


If your pain or swelling persists despite conservative treatments such as rest, ice, and NSAIDs, your doctor may inject cortisone into your knee, a powerful medication that relieves inflammation.

An example of a knee condition that may require a cortisone injection is knee osteoarthritis. Cortisone is a powerful drug that can have side effects, so injections should be used with caution.


Depending on your diagnosis, other medications may be needed, such as a disease-modifying antirheumatic drug (DMARD) to treat rheumatoid arthritis, antibiotics to treat an infected knee, or oral steroids to treat a gout flare.

Complementary and alternative treatments

Various mind and body treatments, such as acupuncture and tai chi, can be used to treat knee pain, especially knee osteoarthritis.

Once popular, dietary supplements like glucosamine and chondroitin are no longer used to treat knee osteoarthritis. This is due to the lack of benefit from them based on scientific research; although some people may feel mild relief. As with any medicine, vitamin, or supplement, be sure to speak with your doctor first before taking them to make sure they are safe for you.


Surgery is usually for specific diagnoses, such as:

  • Certain types of ligament injuries or knee joint dislocations.
  • Certain knee fractures
  • Certain infected knee joints that require surgical drainage
  • Some advanced cases of osteoarthritis of the knee joint.


To prevent knee injuries and / or prevent the progression of chronic knee conditions like osteoarthritis, there are several ways you can take advantage of:

  • Lose weight if you are overweight or obese
  • Strengthen and stretch quadriceps and hamstrings
  • Do a low intensity aerobic exercise that strengthens your muscles by reducing stress on your knee, such as swimming or biking.
  • Wear knee pads when working on your knees.

Get the word of drug information

Treatment for knee pain depends entirely on the cause of the problem. Therefore, it is imperative that you receive a diagnosis and understand the cause of your symptoms before embarking on a treatment program. If you have not been diagnosed, you should seek medical attention before beginning any treatment plan.

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