There are a number of potential causes of pain when bending the knee. One of the most common is patellofemoral pain, which is inflammation or irritation of the tissue around the knee joint. An acute injury, such as a ligament sprain, is another common cause. Overuse injuries such as patella tendinitis may result in pain when bending the knee, although most people find these conditions most painful when a force is put through the joint. Arthritis of the knee joint is another common cause.
Knee pain, especially when bending the knee, is often caused by irritation of the tissue around the joint. This can be caused by overuse or a direct impact and is often referred to as patellofemoral pain. The underlying causes of this discomfort can be overloading the joint while playing sports, weak quadriceps muscles, and even frail hip muscles. This sort of pain is usually treatable by a physiotherapist as long as the underlying cause can be determined.
There are a number of acute injuries that can cause pain when bending the knee. The ligaments that keep the knee stable, for example, can become sprained or ruptured. This results in pain, swelling, and sometimes instability in the joint. Acute knee injuries are often caused by twisting movements during sports, and treatment depends on the severity of the problem. If a ligament has been severely damaged, surgery may be required, but minor injuries can be treated with rest and physiotherapy.
Overuse injuries are common in and around the knee joint because the area is placed under a lot of stress during most activities. Aside from patellofemoral syndrome, the two most common forms of overuse injury are patella tendinitis and iliotibial band syndrome (ITBS). Both can cause pain when the knee is bent. Treatment for these types of conditions usually starts with time off from any activity that causes pain as well as a rehabilitation program to strengthen weak muscles.
Knee arthritis can also cause pain. Both osteoarthritis, which is the result of long term damage to cartilage, and rheumatoid arthritis, which is an inflammatory condition, can both adversely affect the knee. Symptoms of this condition include pain when bending the knee, stiffness that gets worse in the morning, and locking of the joint. There is no cure for arthritis, but the condition can be managed by strengthening and stretching the muscles that support the joint.