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Often times, because the femur is part of the knee joint, an injury to the femur can result in knee pain. The most common injury to the femur that will cause knee pain is a distal femur fracture. Distal femur fractures are fractures that occur at the base of the femur, where it connects to the knee. This kind of fracture is common in older people, as well as those who experience high energy injuries. This type of injury can cause a misshapen knee, tenderness, swelling, bruising, and pain when pressure is put on the knee.

Quadriceps Tendon

Quadriceps tendon tears often occur in older people who engage in running or jumping sports. These tears can be either partial or complete and often happen to people who have weakened tendons. Weakened tendons can result from tendonitis or chronic diseases like rheumatoid arthritis or chronic renal failure.

Quadriceps tendon tears can lead to tenderness, swelling, cramping, inability to straighten the knee, weakness when walking, or a depression above the knee where the tendon was torn.


Patellar dislocation, or unstable kneecap, occurs when the patella slips out of place and becomes partially or completely dislocated, causing pain. Patellar dislocations are most often caused by blows to the knee or falls. Anyone who has suffered from a patellar dislocation may experience pain in the knee, feeling the patella slip out of place, swelling, or a distorted shape of the knee.

Runner’s knee or patellofemoral pain is a common injury with athletes who regularly put stress on their knees. This injury causes soreness under the kneecap which can increase when the knee bends during everyday activities like walking up stairs or sitting for extended periods of time.


Cartilage is an elastic tissue that covers the ends of the long bones at the knee joint, protecting the joints and serving as a shock absorber. Although it is flexible and tough, it is still relatively easy to damage. Typically, damage to the knee cartilage is caused by direct trauma or twisting of the knee, such as from a bad fall, auto accident or direct blow to the knee during sports activities. Age-related wear and tear as well as a lack of mobility can also cause damage, as our joints need regular movement to remain fluid and healthy.

Symptoms of cartilage damage in the knee may include joint pain, inflammation, and joint stiffness or “locking of the knee,” especially after rest.

Patellar Ligament

The patellar tendon extends down from the patella bone to the tibia. Patellar tendon tears can be either partial or complete and are often caused by jumping or falling injuries, patellar tendon weakness (caused by patellar tendonitis or chronic diseases that disrupt blood supply), or previous surgery around the tendon. Symptoms may include an indentation at the bottom of the kneecap, difficulty walking, tenderness, mobility of the patella (which is no longer secured to the tibia).


The meniscus are the two pieces of cartilage between the femur and tibia (singularly pronounced menisci). They cushion the bones from the impact that accompanies exercises such as walking, running and jumping. Meniscus tears are often the result of high impact athletic injuries. People who experience a menisci tear may feel a pop when the tear actually occurs. Afterwards there may be pain, swelling, or immobility of the knee.


Knee ligament injuries are extremely common, especially amongst athletes involved in contact sports like football and basketball. However, these injuries can happen to anyone at any age. Often times, ligament tears occur from changing direction suddenly or twisting while engaged in physical activity.

The ligaments of the knee are divided into two groups, collateral ligaments and cruciate ligaments. The collateral ligaments include the medial collateral ligament (MCL) and the lateral collateral ligament (LCL). The anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) make up the cruciate ligaments.

There are three grades of ligament sprains.

  • Grade 1: The ligament is stretched, but still able to support the knee.
  • Grade 2: The ligament is stretched to the point that it is loose and cannot completely support the knee. This sprain can be considered a partial tear.
  • Grade 3: The ligament is completely torn and is unable to provide any support for the knee.

It is possible to injure more than one ligament at a time. With multiple ligaments torn, partially torn, or stretched, blood supply to the knee and nerves will be affected.

Injuries to the ligaments may result in pain, swelling, inability to walk properly, or an unstable feeling in the knee.

Diagram Your Pain.

Knee Pain Diagram Knee Pain Diagram 2