Knee pain: symptoms, causes and treatment options

Knee pain can be caused by an accident during sport or minor trauma. However, it can also occur gradually due to chronic overuse and signs of wear and tear. Immediately after an accident, the injury should be examined by a specialist anyway to avoid the risk of permanent damage. To prevent chronic, gradually developing pain from permanently reducing your quality of life, you should also consult a doctor who can identify the cause at an early stage and provide suitable treatment.

Structure of the knee joint

In order to better understand knee pain and its cause and to learn to localize it better, it helps to familiarize yourself with the structure of the knee joint. As the largest joint in the human body, the knee joint has a very complicated structure. It is a hinge joint that can alternate between flexion, extension and slight rotation. The knee joint consists of the patellofemoral joint (= joint between the femur and patella) and the actual knee joint (between the femur and tibia). There are two cartilage discs called menisci between the femur and tibia. Articular cartilage surrounds the ends of the femur and tibia to enable friction-free movement. There is also cartilage on the back of the kneecap. The entire knee joint is surrounded by a joint capsule made of connective tissue, which is lined with mucous membrane on the inside. This mucous membrane produces the synovial fluid, which in turn contributes to better friction quality and nourishes the cartilage.

A complex interplay of ligaments, muscle attachments and tendons stabilize the joint under load. In simple terms, there are 4 main ligaments that protect the joint against major axial deviations and rotational movements:

Symptoms of knee pain

Knee pain manifests itself with different symptoms that occur in different areas of the knee and can give an indication of the cause. Depending on the cause, the pain can occur at rest or during exercise, suddenly or gradually, temporarily or chronically. It can be felt at the beginning of a movement as start-up pain or permanently during movement. The pain can be dull, stabbing or burning. It is sometimes accompanied by swelling or overheating of the joint. In individual cases, movement restrictions may occur, which can be very unpleasant, especially if the joint is not fully extended.

Knee pain symptoms

Causes of internal (medial) knee pain

Knee pain can occur suddenly during exertion, but also at rest. The knee may hurt when pressure is applied to the inside.

Knee pain in the hollow of the knee

Knee pain in the hollow of the knee is often caused by a Baker’s cyst, which is a fluid-filled cavity. The cyst is usually associated with a knee joint effusion and can be felt in the hollow of the knee once it reaches a certain size. When bending the knee , this cyst can cause a feeling of pressure. The rupture of the cyst causes severe pain. Other causes of pain in the hollow of the knee include

Inflammation as a cause of knee pain

Knee pain can be caused by non-bacterial inflammation, which includes rheumatic diseases and various metabolic disorders. Bacterial inflammation can also cause knee pain.

Rheumatoid arthritis is chronic and usually occurs in episodes. Immune cells attack the synovial membrane. The resulting inflammatory substances can destroy joint cartilage and connective tissue.
Osteoarthritis is an inflammatory wear and tear of the joint in which the cartilage cover and the meniscus gradually wear away and the bones rub against each other without protection.
Ankylosing spondylitis is a rheumatoid disease that causes inflammation and curvature of the spine. As patients try to compensate for the pain by bending their knees, this results in knee pain.
Psoriatic arthritis is also a rheumatoid disease. This chronic joint inflammation is associated with psoriasis. If the knee joint is affected, the pain intensifies in phases.
Rheumatoid diseases include reactive arthritis, which can lead to inflammation of the knee joint following a bacterial infection of the urinary tract, genitals or intestines.
Systemic lupus erythematosus is an autoimmune disease. The body's own cells are attacked by the immune system. Painful inflammation of the synovial membrane in the knee joint occurs due to deposits of immune complexes consisting of antibodies and attacked cell structures.
Rheumatic fever is caused by streptococci (bacteria) and can affect the knee joint, other joints and even the heart.
Gout is caused by an increased uric acid content in the blood. The excess uric acid is deposited in various joints, including the knee joint, and leads to severe pain.
Pseudogout is caused by calcium salt crystals deposited in the cartilage, which cause symptoms similar to gout.
Bursitis can be triggered by overuse, injuries, but also by gout, diabetes mellitus, infections and immune disorders.

Risky sports that promote knee pain

The knee joints are subject to particularly intense strain in various sports that are characterized by abrupt stopping movements and changes of direction, such as tennis, handball, soccer, martial arts, field hockey or alpine skiing. Damage to the anterior cruciate ligament, meniscus tears, ligament injuries, kneecap dislocations and chronic overuse syndromes are known problems in these sports. Swimming can also cause knee problems due to the twisting movements.

How knee pain can affect you

Knee pain can severely restrict quality of life, especially if it has already become chronic. If movement is severely restricted, prolonged absence from work can be the result. Everyday activities and sporting activities are only possible to a limited extent or not at all. Depending on the individual demands on the joints, the threshold of suffering is reached sooner or later.

Knee pain in runners

Runners are often affected by knee pain as it can lead to overloading. A tendon sheath guides and supports the thigh and hip muscles. During the strain of bending and stretching while running, this tendon sheath slides over a bump on the outside of the knee. This causes irritation, which can often extend to the bursa. With runner’s knee, pain occurs on the front and outside of the knee. Long-distance runners are most affected , but soccer and tennis players are also affected. Runner’s knee can be understood as an overuse syndrome, which can also be a warning sign of possible overtraining. It is important that the adjacent joints are always examined as well, as e.g. a weakness of the hip muscles or a fallen arches due to excessive running training can be the cause of runner’s knee.

Exercises designed to preventively protect the knee joint:

You can use various exercises to prevent knee problems and prevent injuries. Squats on both legs, standing on one leg with a slightly bent knee, lunges backwards and forwards or one-legged stands in a stepping position are all suitable. To prevent incorrect postures during the exercises, ask a physiotherapist to show you the exercises beforehand and do them at home in front of a mirror.

Do the exercises every day, but don’t put too much strain on your knees. A good indicator of overloading is the occurrence of knee joint effusion after training. You should then reduce your training a little and cool the joint again.

When should you consult a doctor if you have knee pain?

After a traumatic injury, you should definitely have your knee pain checked out by a specialist. Redness, swelling, restricted movement and pain when climbing stairs should definitely be examined by a specialist. You should also see a doctor if your pain has come on slowly and gradually and persists for several days despite rest. Once overuse syndromes have become chronic, rehabilitation usually takes much longer than if they are discovered at an early stage.