Knee Pain
Knee pain affects people of all ages and can make everyday activities difficult. Injuries, overuse, and conditions like arthritis most often cause knee pain. Simple actions such as walking, running, or even standing can become uncomfortable because of these issues.
Sports or physical work often injure the ligaments, muscles, or cartilage in the knee. Repetitive movements can also cause pain and swelling. Health conditions like osteoarthritis and rheumatoid arthritis can cause knee pain for both younger and older adults.
Definition of Symptom
Knee pain means feeling discomfort or soreness in one or both knees. It can feel sharp, dull, aching, or burning. The pain may appear suddenly or develop over time. Common signs and symptoms include:
- Swelling
- Stiffness
- Redness or warmth
- Weakness or instability
- Popping or crunching noises
- Difficulty straightening the knee
These symptoms can vary in intensity and duration. Some people experience pain only during certain movements, while others feel it even at rest. Where you feel pain can help point to possible causes. For example, pain in the front of the knee may come from the kneecap, while pain on the sides could be from ligament or meniscus problems.
Knee pain itself is not a disease. It is a sign that something may be wrong inside or around the knee joint. Causes can range from injuries, such as sprains or tears, to long-term problems like arthritis.
Possible Causes/Diseases Condition
Many things can cause knee pain. Sports or very active people often tear a ligament or cartilage, leading to swelling, pain, or trouble moving the knee. Arthritis is a frequent cause of knee pain. There are different kinds, including:
- Osteoarthritis: The most common type, happens from wear and tear over time.
- Rheumatoid Arthritis: The immune system attacks the joints.
Other conditions can also affect the knee. Patellofemoral pain syndrome causes pain in the front of the knee, especially when climbing stairs or sitting for a long time. Sprains, strains, or fractures from falls, accidents, or sudden movements can cause knee pain. Tendonitis means the tendons become swollen, usually from overuse. People who run or jump a lot may get this problem.
Bursitis means the small fluid-filled sacs in the knee become swollen, causing discomfort, especially after kneeling for a long time. Iliotibial band syndrome affects the outer part of the knee. Runners and cyclists often get this when the band becomes tight or irritated. Below is a table showing some causes and their main features:
| Cause | Main Feature |
|---|---|
| Osteoarthritis | Wear and tear, stiffness |
| Rheumatoid arthritis | Swelling, joint pain |
| Torn cartilage | Clicking, locked knee, pain |
| Patellofemoral pain syndrome | Pain in front of knee, with activity |
| Tendonitis | Soreness, swelling |
| Bursitis | Swelling, tender to touch |
| Iliotibial band syndrome | Pain on outer knee, worsens with use |
Other Non-Disease Causes
Knee pain does not always come from diseases like arthritis. Several non-disease causes can lead to knee discomfort.
| Cause | Example Activities | Possible Symptoms |
|---|---|---|
| Overuse/Repetitive Motion | Running, jumping | Soreness, stiffness |
| Mechanical Problems | Flat feet, leg alignment | Pain during movement |
| Obesity | Everyday movement | Aching, swelling |
| Lack of Flexibility | Inactivity | Tightness, discomfort |
- Overuse and Repetitive Motion: Doing activities that put repeated stress on the knee, like running or jumping, can cause pain. This often leads to problems like tendinitis or bursitis. People who start a new workout routine without proper conditioning are at higher risk.
- Mechanical or Structural Issues: The way a person moves or the shape of their legs can create extra pressure on the knee. Problems like flat feet or misaligned joints change how weight is spread out and may lead to pain during normal activity.
- Obesity: Carrying extra weight puts more strain on the knee with every step. Over time, this can cause pain even without injury or disease.
- Lack of Flexibility or Muscle Imbalance: Weak thigh or hip muscles make the knee work harder. Not stretching or having tight muscles may also lead to soreness or discomfort during daily activities.
How It Causes The Symptom
Knee pain can start when tissues inside or around the joint are damaged or stressed. Injuries, overuse, or disease can cause this. Common ways knee problems cause pain:
- Injury: Tearing a ligament, like the ACL, or damaging cartilage can make the knee hurt. Swelling often follows, making it hard to move.
- Overuse: Repeating the same motions, such as running or kneeling, can irritate tendons and other soft tissues.
- Arthritis: Conditions like osteoarthritis break down the cartilage that cushions the bones, causing joint pain and stiffness.
- Inflammation: Infections or diseases can lead to swollen tissues and more discomfort.
| Cause | How It Produces Pain |
|---|---|
| Ligament Tear | Unstable joint, swelling, pain |
| Cartilage Tear | Sharp pain, locking or catching |
| Overuse | Dull ache, tingling, soreness |
| Arthritis | Stiffness, aching, swelling |
Swelling and heat in the knee show that the body is reacting to injury or irritation. Fluid can build up, pressing on nerves and adding to the pain. If the knee joint is out of position or wears down, bone may rub on bone.
This leads to more pain and can limit movement. Even small problems, like mild inflammation, may cause aches or make the area feel tender. Sometimes, pain comes only with movement, but it can also be there when resting.
Possible Complications
If people do not manage knee pain, it can lead to long-term problems. Chronic pain can make it hard to move, work, or do daily activities. Untreated knee problems may cause joint instability, raising the risk of falls and more injuries. Swelling or redness that does not go away could mean there is an infection or inflammation that needs medical attention right away.
Some people lose movement in their knee. The joint may become stiff and lose flexibility over time. Weak muscles around the knee can develop because pain keeps people from being active. This weakness can make walking or climbing stairs difficult. When bone or cartilage damage is not fixed, the joint may wear down. Over time, this may lead to osteoarthritis or the need for knee replacement surgery.
| Complication | Possible Result |
|---|---|
| Chronic pain | Reduced activity, poor sleep |
| Stiffness | Trouble bending or straightening |
| Swelling/infection | Fever, pain, joint damage |
| Instability | Risk of falls, more injuries |
| Weakness | Trouble walking, poor balance |
| Arthritis progression | Joint damage, possible surgery |
When to Seek Medical Attention
Knee pain can sometimes be managed at home, but there are signs when seeing a doctor is important. Don’t ignore these warning signals, as waiting may make things worse. See a doctor if any of these happen:
- The knee looks deformed or bent in an unusual way.
- Abrupt and intense swelling manifests.
- You hear or feel a popping sound at the time of injury.
- You cannot put weight on the knee.
- Pain is very intense and does not get better with rest.
- The knee feels unstable or gives out.
- You notice signs of infection like fever, redness, or warmth.
- The pain lasts for more than a few days.
| Symptom | What It Might Mean |
|---|---|
| Severe swelling | Possible ligament injury |
| Cannot bear weight | Serious sprain or fracture |
| Deformity | Dislocation or fracture |
| Redness/fever | Possible infection |
If pain interferes with daily activities, see a doctor. Ongoing or worsening pain means you should talk to a healthcare provider to get the right care.
