Knee pain is a pretty common complaint that affects people in all different age groups. There are many causes of knee pain. Pain can be the result of an injury or it can be from different medical conditions such as gout, arthritis and infections. Minor knee pain responds very well to different self-care methods. A person with this type of injury might benefit from physical therapy and perhaps a knee brace to help relieve some of the pain. In more extreme cases, an individual might require some type of knee surgery to repair the injury.

Although the severity and location of the knee pain might be different from person to person, the signs and symptoms are usually fairly consistent. For example, one might experience:

  • Swelling
  • Stiffness
  • Redness
  • Warmth to the touch
  • Instability or weakness
  • Noises that sound like crunching or popping
  • Inability to fully straighten the knee

You should consider seeing a doctor if:

  • You can’t bear weight on your knee
  • Have marked knee swelling
  • You cannot fully extend or bend your knee
  • Notice a significant deformity in your leg or knee
  • Have a fever along with redness, pain and swelling of your knee
  • You feel as though your knee is unstable or “gives out”

Common injuries include:

  • ACL injury: a tear of the anterior cruciate ligament (ACL) which is one of the four ligaments that connects your shinbone to your thighbone. This injury is failry common in people who play sport that require quick changes in direction
  • Torn meniscus: the meniscus is a type of cartilage that acts as a shock absorber between your shinbone and thighbone. If you suddenly twist your knee, you might tear the meniscus.
  • Patellar tendinitis: this is an irritation and inflammation of the tendons which attach muscles to bones. Individuals involved in sports where a lot of jumping takes place are prone to develop patellar tendinitis.

Sometimes, knee pain isn’t due to an injury. Instead, it is due to mechanical problems of your body. These mechanical problems include:

  • Loose body: Occasionally, injury or degeneration of cartilage or bone causes a small fragment of cartilage or bone to break off and float in space. This usually does not create any problems. However, if it interferes with the movement of the knee joint, it can cause pain.
  • Iliotibial band syndrome: The iliotibial band is the ligament that extends from the outside of your pelvic bone to the outside of your tibia. When it becomes too tight, it rubs against the outer portion of the femur and causes pain.
  • Dislocated kneecap: This occurs when the patella, the bone that covers the front of the knee, slips out of place. It usually goes to the outside of your knee and you are sometimes even able to see the dislocation.
  • Hip or foot pain: When someone struggles with hip or foot pain, it may cause a change in the way they walk in order to take weight off of these painful joints. However, problems in the hip or foot can actually cause pain to the knee because of the added stress that is put on the knee when trying to take weight off of the hip or foot.

You are at an increased risk of experiencing knee problems if you have:

  • Excess weight: Being obese or overweight puts extra stress on the knee joints and during seemingly ordinary activities, like walking or taking the stairs, can do damage to the knees. It also increases your risk of osteoarthritis.
  • Biomechanical problems: Structural issues can put you at an increased risk for knee problems. For example, having one leg shorter than the other, misaligned knees or flat feet can cause knee issues.
  • Lack of muscle flexibility or strength: One of the leading causes of knee injuries include: lack of strength and flexibility. Tight or weak muscles give less support to the knee as they aren’t able to absorb enough of the stress that is put onto the joint.
  • Play certain sports: Certain sports put more stress on your knees than others and can increase your risk of an injury to the knee.
  • Previous injury: Having had a previous knee injury makes you more susceptible to future knee pain.

Mayo Clinic (2014). Knee Pain.