Knee pain includes pain in or around the knee, suggesting an issue of the knee joint itself or the soft tissue around the knee. The knee joint consists of the femur (thigh bone), the tibia (shin bone), the fibula (smaller bone alongside the tibia), and the patella (knee cap). There are two pieces of cartilage called the medial and lateral menisci in the knee joint meant to absorb shock and cushion the bones involved. Then there are ligaments that provide stability, which includes the anterior cruciate ligament, the posterior cruciate ligament, lateral collateral ligament and medial collateral ligament. Finally there’s the tendons that connect the bones of the knee to all the muscles that cross it, to include most of the hamstring, quad, and calf muscles. Damage to any of these components of the knee joint can lead to knee pain.

Depending on the cause of the knee pain, it can feel a variety of different ways, and where the pain is coming from can point to the cause. Knee pain can be chronic, acute, or activity related. In some cases, proper movement will alleviate the pain or by contrast only certain movements bring it on. The pain can also be accompanied by stiffness, soreness, bruising, and inflammation. It is a common complaint that affects people of all ages, and being inactive or overweight increases the risk of knee problems.

The symptoms will depend on the cause of the pain, and the pain can come on suddenly, especially if it’s from an injury, or slowly and over time. It can be felt deep in the knee joint, meaning it may be due to wearing down of cartilage and from bone on bone grinding, and be accompanied by stiffness and gait abnormalities. Some people even notice popping or crunching noises during certain activities. These sounds can be heard in a healthy joint, too, but when it is coupled with pain then there is a deeper issue that needs to be addressed. More symptoms include soreness, bruising, inflammation, redness, warmth to the touch, weakness, instability, and even joint destruction if left untreated. Pain and swelling can be worse in the morning or after sitting for long periods of time. Injuries to the knee can cause bleeding or lead to infection, which can come with a fever.

Knee pain can worsen with improper movement such as exercising with poor form, improper stretching, or not warming up and cooling down when performing physical activities. Improper form leads to an uneven wear of the cartilage in the knee joint. The pain can result in a sedentary lifestyle, which can lead to a further weakening of the joint, limited range of motion, less-than smooth movement of the joint, an inability to fully straighten or bend the leg, and imbalances in the structure of the knee.