The knee joints are the largest in your body and play a crucial role in your mobility. The knee is a complex structure, consisting of bones, tendons, two types of ligaments, and two types of cartilage. This complexity means that the knee is also susceptible to a variety of medical issues. Common injuries include fractures, dislocations, tendon tears, and ligament tears. Many of these occur due to physical activity, especially participation in sports, though lifelong wear and tear is also a factor. Knee problems are a prevalent medical issue; one study found that roughly one in four adults suffers from significant knee pain, most frequently in persons 50 years or older.

The defining symptom of a knee condition is pain. The source of pain can vary, depending on the location of the cause and whether it is constant or intermittent (typically movement-specific). Other symptoms associated with knee conditions are:

• Crunching or popping noises

• Feelings of instability

• Grating or grinding sensations

• Inability to straighten your leg

• Inflammation

• Stiffness