Knee Pain

Knee pain can be one of the most frustrating ailments to navigate. Knee pain has many different causes, and it results in difficulty moving a part of the body used frequently. 

In this article, Health Report Live covers the physiology of the knee, root causes for knee pain, and treatment to help resolve knee pain.

Facts You Should Know About Knee Pain

Some people do not realize both the importance and the sensitivity of the knee until they are experiencing knee pain. 

While knee pain can sometimes indicate a serious injury, there are many causes and degrees of severity for what generally gets classified as knee pain. 

Here we will explore all the elements of knee pain and what to do should you be experiencing knee pain.

What Is Knee Pain?

People experience knee pain in various ways, either as a total discomfort around the entire area or a specific twinging or sensitivity in a particular part of the knee.

The Mayo Clinic notes that knee pain may result from an injury, such as a ruptured ligament or torn cartilage. Medical conditions such as arthritis, gout, and infections may also be at the root of knee pain. 

Some types of knee pain are relatively minor and only require in-home treatment to resolve. In contrast, other types of knee pain may indicate damage requiring surgery to adequately resolve the issue.

Brief Anatomy of the Knee

The knee is one of the most vital joints in the body. It is also one of the most complex, with bones, ligaments, cartilage, and tendons joining the upper and lower leg.


Four bones come together at the knee joint, including the patella (or kneecap), positioned at the front of the knee joint. 

The femur, connecting the knee to the pelvis along the thigh, is a significant part of the knee’s anatomy, as are the tibia and fibula, the two primary bones in the lower leg.


A number of the most concerning knee injuries involve the ligaments. Four ligaments connect the femur to the tibia and are vital to stability and flexibility. 

  • The anterior cruciate ligament (or ACL) prevents the femur from sliding backward on the tibia (or the tibia sliding forward on the femur).
  • The posterior cruciate ligament (or PCL) prevents the femur from sliding forward on the tibia (or the tibia from sliding backward on the femur).
  • The medial and lateral collateral ligaments (MCL, LCL) prevent the femur from sliding side to side.


The knee also utilizes cartilage for movement and stability.

Articular Cartilage

A Mayo Clinic article observes, “Both the femur (thigh bone) and tibia (shinbone) are covered with small, white, well-lubricated articular cartilage that makes the knee joint glide and function well. Healthy articular cartilage is a central component of a normal healthy joint.”

Meniscal Cartilage (Meniscus)

In addition to articular cartilage, the meniscus plays a vital role in mobility. As the Mayo Clinic observes, the meniscus is “two C-shaped pieces of cartilage that act like a cushion between your shinbone and your thighbone.”


Tendons also figure into the knee’s complex anatomy. They are thick bands of connective tissue that connect muscles to bones, and they are sometimes involved in knee pain that people experience. 

According to a UT Health San Antonio roundup, tendons associated with the knee include the quadriceps tendon, the patella tendon, hamstring tendons, and the iliotibial band.

Joint Care

Taking care of your knee joints can be one of the most important preventative measures in warding off knee ailments. 

These include doing exercises to strengthen the muscles around the knee, stretching at least daily to encourage flexibility throughout the knee’s tendons and ligaments, and taking supplements like glucosamine and chondroitin (believed to help build up or protect cartilage). 

People who are overweight can also reduce pressure on the knee joint by losing weight. Each pound lost works out to four pounds less pressure on the knee.


Though the severity of pain and discomfort is not necessarily consistent with the severity of the injury, a knee has a few specific ways of letting a person know there is some kind of injury.

As the Mayo Clinic notes, there are a few common symptoms that people experience due to a knee injury. Those include:

  • Swelling or stiffness in the knee
  • Redness and warmth to the touch
  • A feeling of weakness or instability
  • Noises (including crunching and popping)
  • Not being able to fully straighten the knee

More serious symptoms, which should be indicators of needing medical attention, include:

  • Not being able to bear weight on the knee
  • A feeling of the knee “giving out” or otherwise being significantly unstable
  • Significant and noticeable knee swelling
  • Not being able to fully extend or even flex the knee
  • Obvious deformity in the leg or knee
  • A fever accompanying redness, pain, and swelling in the knee
  • A known injury resulting in severe knee pain


Knee Arthritis

For some people, knee pain is caused by arthritis, though there are many different types, ranging from treatable, acute conditions to more chronic types of arthritis that might require longer-term management.

The most common types of arthritis leading to knee pain — out of, remarkably, more than 100 varieties, include:

  • Osteoarthritis, described by the Mayo Clinic as a “wear-and-tear condition that occurs when the cartilage in your knee deteriorates with use and age,
  • Rheumatoid arthritis, an autoimmune condition that can affect the knees and other joints in the body — while it is chronic, it can vary in severity and range from intense flare-ups to being virtually unnoticeable,
  • Gout, an arthritic condition that happens when uric acid crystals build up in the knee joint,
  • Pseudogout, caused by calcium crystals in the knee joint fluid, and as its name suggests, is often mistaken for gout, and
  • Septic arthritis is a condition resulting from an infection that can cause swelling, pain and redness — and, if unchecked, can quickly cause extensive damage to the knee cartilage. If a fever accompanies those common knee pain symptoms, it is wise to rule out septic arthritis.

Knee Ligament Injuries

An injury to one of the ligaments can lead to long recovery times. As sports fans know, tears to the ACL or MCL can sideline athletes for months as they undergo the needed recovery and rehab process. 

As the Johns Hopkins site notes, a “sudden twisting motion (when the feet stay planted one way, but the knees turn the other way)” can result in an ACL tear. 

A PCL injury is more commonly associated with direct contact injuries, like a car accident or being tackled in a football game. 

As that site points out, it is also notable that a cruciate ligament injury does not cause pain. Instead, the person may hear a popping sound as the injury occurs. 

That can then be followed by the leg buckling when trying to stand on it and then swelling. It is important to get an MRI if you suspect you have suffered a ligament injury.

Torn Knee Cartilage (Meniscus)

Meniscus tears are among the most common of all knee injuries, often caused by putting weight on the knee and then twisting or rotating it. 

The Mayo Clinic site advises that while you might feel pain, stiffness, swelling, and might have issues extending it fully, at-home measures might be enough to address the issue. 

“Conservative treatment — such as rest, ice and medication — is sometimes enough to relieve the pain of a torn meniscus and give the injury time to heal on its own In other cases, however, a torn meniscus requires surgery.”

Patellar Tendonitis and Tear

The patellar tendon connects the kneecap to the shinbone, and overuse can lead to this common variant of knee tendonitis. 

The tendon helps muscles at the front of the thigh in running or other athletic activities, so it is something that fit people can experience following exercise. (Its common name is jumper’s knee, to suggest fitness.) 

It can also impact people who are simply engaged in more common daily activities, and as it gets worse, it can impede people as they walk up stairs or even rise to a standing position. Ice and rest can be enough to take care of a bout of tendonitis.

However, it is important to take care of tendonitis before it worsens. As a Mayo Clinic article notes, repeated instances of stress on the patellar tendon cause tendonitis. 

“The stress results in tiny tears in the tendon, which your body attempts to repair,” the article notes, before clarifying that “as the tears in the tendon multiply, they cause pain from inflammation and weakening of the tendon.” 

When this tendon damage persists for more than a few weeks, it graduates to a condition known as tendinopathy.

If you try to “play through it,” whether engaging in your usual athletic activity or just trying to get around normally, you might make it worse.

Patellofemoral Pain Syndrome

Patellofemoral pain syndrome is another condition that gets labeled “runner’s knee” or “jumper’s knee,” broadly defined as pain in the front of the knee (the kneecap or patella). 

According to Cleveland Clinic, there are a range of causes for this syndrome, including “overuse of the knee joint, problems with kneecap alignment, weak muscles surrounding the knee, improper equipment use or sports training techniques, changes to footwear, and hard playing surfaces.”

If you are experiencing a dull pain or an ache in the front of the knee, or you are experiencing pain associated with bending the knee, you might be experiencing this particular syndrome.

Non Injury Knee Pain

Of course, pain does not have to be attributable to just injury: The variety of arthritis-related ailments afflicting some knee pain sufferers are not injury-related yet cause issues.

Other Common Causes

Bursitis is a fairly common knee ailment that does not involve injury or even overuse. Bursa are tiny sacs filled with fluid inside the knees that help cushion the bones in the knee joint. 

If bursa becomes infected or otherwise irritated, they can become inflamed. Bursitis can be extremely painful; if you are experiencing any redness in the knee joint or tenderness or even a fever, bursitis might be the cause.

A Baker’s cyst is another ailment that affects the knee though it is not technically an injury. According to the Orthopaedic & Spine Center of the Rockies, a Baker’s cyst is also known as a popliteal cyst. It is located at the back of the knee and filled with fluid. 

The swelling it causes can restrict movement. It can actually accompany an undiagnosed knee injury. However, in many cases, it will go away of its own accord. In some cases, though, it might require draining to resolve it.

If you are experiencing hip or foot pain, compensating for that might cause you to move or even just hold your leg in a way that causes a knee issue.

Less Common Causes of Knee Pain

Osgood-Schlatter disease is caused by irritation of the bone growth plate. As the John Hopkins site points out, it is a condition that will typically resolve with time, ice, and rest, and surgery is not usually needed to address it. Some kinds of cancer may result in knee pain, such as osteosarcoma.

Managing and Relieving Symptoms

If you have knee pain, you will be very interested in trying to resolve it. Here are some recommendations for managing symptoms as they first come up, and then eventually finding relief.

Balancing Rest and Exercise

A number of knee ailments are related to overuse and irritation, and just getting off it can be a huge help. You have likely heard the acronym R.I.C.E. in injury treatment, and the first word in that, of course, is rest. While you might need to keep entirely off it, depending on the nature of what you are dealing with, initially staying off your knee and getting some rest can help you take a beat and keep yourself from exacerbating the injury or pain.

While you might be able to mix in some exercise along the way, you might consider doing low-impact exercises while you are recovering from a knee injury. Taking a few laps in a pool will put far less stress on your knee joints than pulling on your running shoes and pounding the pavement.

Weight Management

Losing weight can be extremely helpful in managing your knee joints over time – though it is admittedly hard to exercise when you are experiencing knee pain, which is where those low-impact exercises can come in. 

Each pound of body weight you lose takes four pounds of force off your knees. That puts you at less risk for a knee injury and allows you to move more.

Heat and Ice Packs

There is a debate between those who favor ice and heat. The authors of the site for OrthoCarolina — which works with pro football players — recommend ice in most situations, including recent injuries. They do note, however, that it is possible to over-ice a part of the body, and people need to be careful. 

They recommend not more than 20 minutes of ice applied, as the narrowing of blood vessels that initially happens with icing will then actually lead to “reactive vasodilation, or widening, of the vessels as the body tries to make sure the tissues get the blood supply they need.”

Heat, on the other hand, can ease spasms in larger muscle groups, but will not typically be helpful for knee issues — especially acute injuries.

Support and Suitable Footwear

It may be helpful to have good support, especially with footwear, to help prevent knee injuries. Experts suggest that flexible and comfortable shoes are best, whereas more rigid shoes with thicker soles billed as “walking shoes” might actually put more of a load on the knees than more comfortable shoes.

Depending on the knee pain – particularly one in which stability is a concern, you might consider a knee brace or a neoprene sleeve worn over the knee to support it.


Paracetamol, also known as acetaminophen — though many refer to it by the Tylenol brand name — is one of the most widely used analgesics in the market. It might have a role in your treatment of knee pain.

Non-steroidal Anti-inflammatory Drugs — Tablets

Many doctors treating knee pain recommend over-the-counter non-steroidal anti-inflammatory drugs (or NSAIDs) for treatment.

Ibuprofen (the active ingredient in Advil) and naproxen (most commonly known by the Aleve brand name) are two typical go-to choices for people trying to resolve knee pain.

Non-steroidal Anti-inflammatory Drugs — Rub-On Painkillers

NSAIDs also come in a topical form. Diclofenac is the active ingredient found in both Voltaren and Pennsaid, and those medicines can be applied directly to the knee to offer potential relief.

Risk Factors

If you have experienced a previous knee injury, you could be at risk for a future knee injury, depending on the nature of your injury and the rehab program you embarked upon. 

Being overweight can also make you more susceptible to knee issues, as can not being active enough to build up the muscles in your legs and around your knees.


It is quite possible, without getting the immediate medical attention or taking the proper precautions required of knee injuries, that what starts as a minor issue can get much worse. 

For example, tendonitis that affects the patella can turn into severe tendinopathy if the tears in the tendon become larger and more pronounced over time. While some knee injuries can be treated at home, others require surgical intervention.

Which Types of Doctors Treat Knee Pain?

While a general practitioner or a family practice doctor will be able to make a basic diagnosis, you will want to see an orthopedic doctor or even a knee surgeon if it is a knee injury that steps up to the level of needing surgical intervention.

How Do I Know if My Knee Pain Is Serious?

The Mayo Clinic advises that if your knee pain is the result of a “particularly forceful impact,” or if your injury is accompanied by fever, significant pain, redness, warmth around the knee joint, or tenderness, those are all signs of injuries that likely require medical treatment. 

However, it also notes, “If you [have] had minor knee pain for some time, make an appointment with your doctor or health care provider if the pain worsens to the point that it interferes with your usual activities or sleep.” 

Remember that some knee injuries, like an ACL tear, might not immediately hurt. Hearing a popping sound with a painless injury is a sign that you might have suffered a significant injury like an ACL tear.

When to Contact a Medical Professional

Certainly, any of the advice above can guide you. Simply, if you do not feel that what you can do at home is enough to sufficiently address the pain you are experiencing, make an appointment with a doctor just to make sure.

What to Expect at Your Office Visit

Your doctor will ask you about your knee pain and try to ascertain when, where, and how it happened. Also, expect the doctor to visually and physically examine your knee to try to determine more about the pain you are experiencing.


Medical History

Your medical history might figure into what is causing your knee pain, including past injuries, whether or not you have had past surgeries, or whether or not you have had cancer.

Physical Examination

Aside from the localized look at your knee, expect the doctor to at least take vital signs and do a cursory check to make sure you are not feverish, have a high pulse rate, or are otherwise experiencing distress.

Imaging or Radiologic Tests

It is possible that your doctor will want to get a quick x-ray of your knee to rule out any major issues. 

However, to get a really good look at what is going on with your knee, an MRI is the gold standard. It is likely your doctor will want one, especially if the doctor thinks a ligament or meniscus injury is involved.

Blood Tests

Blood tests might be necessary — including testing your uric acid levels if your doctor suspects that gout might be the culprit.

Removal of Joint Fluid (Arthrocentesis)

If there is joint fluid that needs to be drained (for lab testing, to relieve pain, or both), your doctor might do an in-office procedure called an arthrocentesis, using a needle to remove fluid. 

It is also possible that in this procedure, the doctor will inject corticosteroids into the joint to address knee pain — though, for some types of knee issues, steroid injections might not be the answer.

Differential Diagnoses

It is possible that your symptoms match more than one diagnosis, so doctors might start with differential diagnoses and then aim to narrow it down to the diagnosis that appears correct.


Stronger Painkillers or Medication

It is possible that you might need medication not available over-the-counter. This may stronger pain medications, muscle relaxants, or even allopurinol to reduce the uric acid levels in your blood.

Physiotherapy or Physical Therapy

It is possible that physical therapy, with the guidance of a professional leading you through various stretches and exercises, can help you resolve your knee pain issues.

Talking Therapies and Pain Management Programs

It is possible that talking therapy or other types of pain management programs are appropriate for your situation. If so, your doctor might point you to resources that will allow you to pursue those avenues.

Complementary and Alternative Therapies

Similarly, there might be additional therapies, like acupuncture, chiropractic treatment, massage, and yoga, that can go a long way toward addressing your knee pain.


Corticosteroid injections are not indicated for all types of knee pain. They can provide pain relief and even healing in some instances.


Some knee injuries, most notably ligament tears, will require surgery as a step toward overall healing. While the surgery itself will not take a great amount of time, the recovery process can be significant. 

An ACL replacement, for example, requires about nine months for recovery. It employs a significant course of physical therapy in order to help a patient return to a full range of motion in the injured knee.

Can Knee Pain Come Back After Treatment?

There is always a chance that knee pain can return after an injury — or that the same knee can be reinjured following recovery. However, medical professionals can help set people on a course for recovery that heals the knee while strengthening the joint and the muscles around it. 

Knee pain, in all its forms, can be intensely painful or insistently nagging at first. However, with treatment and time, a number of people find relief from the pain that ails them. Those people are typically able to resume all their activities.


The best way to prevent knee pain, aside from maintaining a healthy weight to keep stress off your knee joints, is maintaining a healthy level of exercise. This includes low-impact exercise, with plenty of stretching before and after to keep your muscles limber and responsive.

Some people swear by glucosamine and chondroitin, especially people who are getting older. A supplement should be just that, though – a supplement to healthy and principled choices.

Working With Knee Pain

Some people have to try to carry out their daily duties while dealing with knee pain. If you are in that boat, make sure that you are taking the proper precautions to try not to make your injury worse. 

Rest and elevate your leg as much as you can, try not to directly put pressure on your knee joint, and avoid activities that cause you discomfort. It can be challenging, though: Sometimes, the simple act of driving a car can cause you to bend or flex your knee in a way that troubles you.

Research and New Developments

New gains are being made in knee pain therapy as research continues to be funded and carried out. The latest innovations around ultrasound and genicular nerve blocks might not be common in doctors’ offices yet. 

They do, however, represent new frontiers and great possibilities for the future of knee pain treatment.

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Sean Byers, MD

Sean Byers, MD

Sean Byers is currently a Resident in the Internal Medicine program at UTMB. He studied at the University of Queensland School of Medicine as well as received his Master’s in Public Health with a focus in epidemiology and biostatistics at the University of Southern California. His background is in biology, computer science, public health, and internal medicine.

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