Knee Pain

  • Medical Author:
    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Anatomy illustration of the knee.

Knee pain facts

  • Knee pain is a common problem with many causes, from acute injuries to complications of medical conditions.
  • Knee pain can be localized to a specific area of the knee or be diffuse throughout the knee.
  • Knee pain is often accompanied by physical restriction.
  • A thorough physical examination will usually establish the diagnosis of knee pain.
  • The treatment of knee pain depends on the underlying cause.
  • The prognosis of knee pain is usually good although it might require surgery or other interventions.

What is knee pain?

Knee pain is a common problem that can originate in any of the bony structures compromising the knee joint (femur, tibia, fibula), the kneecap (patella), or the ligaments and cartilage (meniscus) of the knee. Knee pain can be aggravated by exercise, affected by the surrounding muscles and their movements, and be triggered by other problems (such as a foot injury). Knee pain can affect people of all ages, and home remedies can be helpful unless it becomes severe.

Quick GuideSlideshow: Exercises for Knee Osteoarthritis and Joint Pain

Slideshow: Exercises for Knee Osteoarthritis and Joint Pain
Find out more about the causes, treatment, and various symptoms of knee pain.

Your Knee Pain: Is It Chondromalacia?

Chondromalacia, technically termed chondromalacia patellae, is the most common cause of chronic knee pain. The condition is also called the patellofemoral syndrome.

Picture of Knee Joint
A female runner helps a male runner experiencing knee pain.

What are knee pain symptoms and signs?

The location of the knee pain can vary depending on which structure is involved. With infection or an inflammatory process, the whole knee might be swollen and painful, while a torn meniscus or fracture of a bone gives symptoms only in one specific location. A Baker cyst will usually cause pain in the back of the knee.

The severity of the joint pain can vary, from a minor ache to a severe and disabling pain.

Some of the other signs and symptoms that accompany knee pain are

  • difficulty walking due to instability of the knee,
  • limping due to discomfort,
  • difficulty walking up or down steps due to ligament damage,
  • locking of the knee (unable to bend the knee),
  • redness and swelling,
  • inability to extend the knee, and
  • shifting weight to the opposite knee and foot.
X-ray of a tibial plateau fracture.

What causes knee pain?

Knee pain can be divided into three major categories:

Below is a list of some of the more common causes of knee pain. This is not an all-inclusive list but rather highlights a few common causes of knee pain in each of the above categories.

Acute knee injuries

Fractures: Direct trauma to the bony structure can cause one of the bones in the knee to break. This is usually a very obvious and painful knee injury. Most knee fractures are not only painful but will also interfere with the proper functioning of the knee (such as kneecap fracture) or make it very painful to bear weight (such as tibial plateau fracture). All fractures need immediate medical attention. Many fractures require significant force, and a thorough examination is performed to detect other injuries.

Ligament injuries: The most common injury is the ACL (anterior cruciate ligament) injury. This is often a sports-related injury due to a sudden stop and change in directions. The remaining ligaments (posterior cruciate ligament, lateral collateral ligament, and medial collateral ligament) are injured less frequently.

Meniscus injuries: The menisci (medial and lateral) are made of cartilage and act as shock absorbers between bones in the knee. Twisting the knee can injure the meniscus.

Dislocation: The knee joint can be dislocated, which is a medical emergency that requires immediate attention. Knee dislocation can compromise blood flow to the leg and have other related problems. This injury often occurs during a motor-vehicle accident when the knee hits the dashboard.

View Osteoarthritis: An Overview and Visual Guide to OA Slideshow Pictures
X-ray of a patellar tendon rupture.

What causes knee pain? (Continued)

Medical conditions

Rheumatoid arthritis is an autoimmune condition that can affect any joint in the body. It can cause severe pain and disability, as well as swelling.

Gout is a form of arthritis that is most commonly found in the big toe, though it can also affect the knee. Gout tends to flare up and is extremely painful during the acute episodes. When there is no flare-up, the knee can be pain free.

With septic arthritis (infectious arthritis), the knee joint can become infected; this leads to pain, swelling, and fever. This condition requires antibiotics and drainage treatments as soon as possible.

Chronic use/overuse conditions

Patellar tendinitis is an inflammation of the tendons connecting the kneecap (patella) to the bone of the lower leg. Patellar tendinitis is a chronic condition often found in individuals repeating the same motion during exercise (such as runners and cyclists).

Patellofemoral pain syndrome is caused by degeneration or stress under the kneecap (patella) where it meets the thighbone (femur). Patellofemoral pain syndrome occurs in runners and cyclists.

Osteoarthritis: A wearing down of cartilage of the joint due to use and age

Other causes

Children can develop inflammation of the point of bony insertion of the patellar tendon (Osgood-Schlatter disease).

A 3-D rendered illustration of the knee, a runner, an electrician kneeling, and an overweight woman performing squats.

What are risk factors for knee pain?

Biomechanics: The knee joint is complicated in its operation and is used frequently throughout the day. Any change in the movement of the joint (leg-length difference, change in walking style due to back problems) can cause subtle changes and cause pain and injuries.

Excess weight: The stress on the knee joint is increased with excess weight. Obesity also increases the risk of osteoarthritis as the cartilage breaks down more rapidly.

Overuse during repetitive motions as are found during certain exercises (jogging, skiing) or work conditions (long periods of kneeling) can cause breakdown of cartilage and lead to pain.

A man with knee pain has trouble walking down the stairs.

When should people with knee pain call a health care professional?

Any pain that does not respond to rest or disappears within a few days should be evaluated by a doctor. In addition, the following are symptoms and signs in the knee that a doctor should evaluate:

  • Swelling
  • Inability to bend
  • Deformity
  • Unable to walk or discomfort while walking
  • Significant pain

What are some of the complications of knee pain?

Frequently, knee pain will disappear without ever finding a specific cause. Depending on the underlying cause of the pain, the condition can progress and lead to more serious injuries or complications. Usually, these complications are long term and result in worsening pain or an increasing difficulty to walk.

A doctor examines a male patient with knee pain.

How do physicians diagnose knee pain?

A health care professional will begin by asking questions related to the person's general health and then specifically to the nature of the knee pain (how long, how severe, does anything make it feel better or worse, etc.).

Next, an examination of the knee will be performed. This will include bending the knee through the full range of motion, checking for stability of the ligaments, and evaluating for any tenderness and swelling. It is often helpful to compare the results of the examination of the painful knee with the other knee. Frequently, this is all that is required to make a diagnosis and start treatment. In several research studies, it has been found that an experienced examiner is as reliable as X-ray examination.

Sometimes the doctor might want to do further studies such as the following tests.

Radiologic tests

Plain X-ray can establish fractures and degenerative changes of the knee.

MRI is used to evaluate the soft tissues of the knee for ligament tears or cartilage and muscle injuries.

Blood tests

If gout, arthritis, or other medical conditions are suspected, a health care professional might order blood tests.

Removal of joint fluid (arthrocentesis)

Some conditions are best diagnosed by removal of a small amount of fluid from the knee joint. During arthrocentesis, a small needle is placed into your joint and fluid is withdrawn. This is done in a sterile method. The fluid is then sent to the laboratory for evaluation. This procedure is especially helpful if an infected knee joint is suspected or to distinguish gout and different forms of arthritis. If there is a collection of blood in the joint due to a traumatic injury, removing the fluid can help relieve the pain.

Physical therapist manipulates the knee of a female patient.

What kind of doctors treat knee pain?

Often knee pain can be evaluated and treated by your primary-care doctor. If the knee pain requires surgery or the cause of the pain needs further evaluation, an orthopedic surgeon will usually be consulted. With arthritis, gout, or inflammatory joint problems a rheumatologist may be consulted.

What is the treatment for knee pain?

Treatments for knee pain are as varied as the conditions that can cause the pain.

Medications

Medications might be prescribed to treat an underlying medical condition or for pain relief.

If you are taking over-the-counter pain medications regularly for your knee pain, you should see your doctor to be evaluated.

Physical therapy

Sometimes strengthening the muscles around the knee will make it more stable and help guarantee the best mechanical movements. This can help avoid injuries or further worsening of an injury.

Injections

Injecting medications directly into your knee might help in certain situations. The two most common injections are corticosteroids and lubricants. Corticosteroid injections can help arthritis and other inflammations of the knee. They usually need to be repeated every few months. Lubricants that are similar to the fluid already in your knee joint can help with movement and pain.

Model of a knee replacement with titanium hinge joint

What is the treatment for knee pain? (Continued)

Surgery

Knee operations range from arthroscopic knee surgery to total knee replacement. Arthroscopic knee surgery is a very common surgical procedure that allows the physician look inside your knee through a few small holes and a fiberoptic camera. The surgeon can repair many of the injuries and remove small pieces of loose bones or cartilage. This is a common outpatient procedure.

Partial knee replacement: The surgeon replaces the damaged portions of the knee with plastic and metal parts. Because only part of the knee joint is replaced, this procedure has a shorter recovery then a total knee replacement.

Total knee replacement: In this procedure, the knee is replaced with an artificial joint.

Other therapies

Acupuncture has shown some relieve of knee pain, especially in patients with osteoarthritis. Glucosamine and chondroitin supplements have shown mixed results in research studies.

Quick GuideSlideshow: Exercises for Knee Osteoarthritis and Joint Pain

Slideshow: Exercises for Knee Osteoarthritis and Joint Pain
A female ices her knee to relieve pain.

Are there any home remedies for relief of knee pain?

Over-the-counter pain medications can frequently alleviate the pain. If someone is taking these medications on a regular basis, he or she should see a health-care professional to evaluate the knee pain for proper diagnosis and to avoid the potential side effects of chronic medication use.

The RICE mnemonic is often helpful, especially for minor injuries:

Rest: Rest the joint, and take a break from your usually activities involving the knee joint.

Ice: Applying ice can help with pain and inflammation.

Compress: A compression bandage can help prevent swelling and help knee alignment. It should not be tight and should be removed at night.

Elevate: Elevation can help with swelling and resting of the knee.

Is it possible to prevent knee pain?

There can be many reasons for knee pain. Therefore, there are different strategies to prevent the pain depending on the underlying cause. Running on soft surfaces or decreasing the amount of running can help if the pain is due to overuse. Avoiding any direct injuries to the knee including wearing a seatbelt can prevent traumatic injuries. Weight loss can be helpful for many different forms of knee pain.

What is the prognosis of knee pain?

Frequently, knee pain will occur for a short period of time and then resolve. Sometimes it can return a few weeks or months later. If your knee pain becomes chronic, it is important to get it evaluated to avoid further damage to cartilage, bones, or ligaments. Prognosis depends on the underlying causes of the pain.

With modern surgical techniques, it's possible to relieve many of the knee pain syndromes and return to an active lifestyle.

Reviewed on 6/20/2017
References
REFERENCE:

Meding, J.B., P.M. Faris, and K.E. Davis. "Bilateral Total Hip and Knee Arthroplasties: Average 10-Year Follow-Up." J Arthroplasty May 22, 2017. Epub ahead of print.

IMAGES:

1.MedicineNet

2.iStock

3."TibPlateauF" by James Heilman, MD

4."Patellar tendon rupture" by James Heilman, MD

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6.iStock

7.Getty Images

8.iStock

9.iStock

10.Getty Images/PhotoAlto

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