The knee is not only our largest joint, it is also often described as the most complicated joint in the body. The sophisticated interplay between the kneecap, meniscus, ligaments, muscles, capsule and tendons makes the knee incredibly resilient: with every step our knees bear a load three times our own body weight.

Going weak at the knees is only a good thing if we’re in love. From a medical point of view, weak knees are a sign of instability.

Read on to learn more about the knees and the most common problems and diseases. You can also find the right contact person to assist with your enquiry.


The knee joint is the largest – and most complicated – joint in the human body. This hinge joint connects the thigh bone (femur) with the shin bone (tibia) and enables us to extend and bend our legs. The knee also permits a certain degree of sideways rotation of the foot and shin bone. These movements are limited by the inner and outer lateral ligaments. The two cruciate ligaments also play a central role. They provide stability at the front and back of the knee.

Between the surfaces of the upper and lower leg bones there is a layer of meniscal tissue. It acts as a buffer and plays a key role in the transmission of force. Like cartilage, the inner and outer meniscus can be damaged. For example, if it slips between the joints during fast rotary movements it can tear or even separate from the bone.

The kneecap, which you can easily feel and move with your fingers, is connected to the femur. The force from the thigh muscles is transmitted via the kneecap to the lower leg.

The knee capsule surrounds the entire knee joint. When the leg is fully extended (straight), the capsule is taut and stable. The tendons are protected by various bursae, which are positioned in places subjected to large amounts of friction.  

Hirslanden Orthopädie, Anatomie des Knies.


1. Femur
2. Patellar ligament
3. Kneecap
4. Cartilage
5. Cruciate ligaments
6. Intra-articular ligaments
7. Meniscus
8. Tibia

Common problems & diseases

Here are some of the common problems and diseases that can affect the knees.

This is not a comprehensive list.

Osteoarthritis of the knee

Osteoarthritis of the knee refers to signs of wear and tear in the knee joint, particularly on the cartilage. The treatment depends on the severity of the pain and includes everything from resting the joint to cortisone injections and surgery.

For more information, see the clinical picture of osteoarthritis and rheumatoid arthritis, chronic polyarthritis


Dislocated kneecap (luxating patella)

If the kneecap becomes dislocated from its usual position, this is known as a luxating patella. Often it moves back into place by itself. However, the more frequently the knee becomes dislocated, the more harm it does – because each time the cartilage gets slightly damaged. And damaged cartilage can later lead to osteoarthritis. A dislocated kneecap can be caused by a fall or a congenital defect. Women are more frequently affected by a luxating patella than men, because women tend to have less pronounced muscles that stabilise the knee joint and hold the kneecap in place. Weak connective tissue can also increase the risk of a dislocated kneecap.

Strengthening specific muscle groups through physiotherapy can help to increase the stability of the joint. If a person has suffered from multiple dislocations then it is worth considering surgery, such as an operation to tighten the ligaments that hold the kneecap securely in its channel of movement.

You can find more information in the clinical picture Patellar dislocation.

Torn cruciate ligament

When the knee twists or buckles, the front or rear cruciate ligaments can tear. Although the cruciate ligaments play an important role in stabilising the knee joint, a torn cruciate ligament does not always require surgery. Depending on the injury and the patient’s needs, sometimes physiotherapy exercises [link] may be enough to sufficiently stabilise the knee joint. Often it takes a while before the patient and the orthopaedic specialist can establish whether the knee joint will remain stable during everyday activities and sport and meet the patient’s individual needs.

If the patient is also suffering from related injuries, such as a pinched meniscus or other ligament injury, then it is usually advisable to undergo surgery – particularly to prevent additional damage to the joint cartilage. Top athletes often get their cruciate ligaments reconstructed using plastic surgery in order to regain full use of the joint.

Further information can be found in the clinical picture Cruciate Ligament Rupture, Rupture of the Anterior Cruciate Ligament.

Patient Q&A

Our medical specialists regularly answer readers’ questions in newspapers, magazines and online. We have put together a few of these questions and answers for you here. Please note that the Q&A is purely informative. The advice provided is not comprehensive and does not substitute a consultation with a medical professional. 

Knee pain after jogging

«For at least a year I have been experiencing pain in my left knee when I jog. The pain comes directly from the front, below the kneecap in my left knee. When I stop jogging, the pain immediately disappears. I also regularly play very competitive tennis, but I never have any pain. And when I’m just walking normally I don’t feel anything. If I jog several times a week then the pain isn’t as bad.»

There are many reasons why people’s knees hurt while they’re jogging. Runner’s knee is very common, however that tends to cause pain on the outside of the knee, which can then spread to the lower front part of the knee. Runner’s knee is caused by inflammation of the bursa and is often related to problems with the structure of the feet. Incorrect foot posture can cause the knees to start hurting. Considering that you only experience pain when you’re running, I suggest you undergo an analysis of your running technique to check the posture of your feet and your shoes. If that doesn’t lead to any improvement, then you should have your knees examined by an orthopaedic specialist or a sports physician.
Dr. med. Toni Held, Sportklinik Basel, Hirslanden Klinik Birshof, Münchenstein

Knee pain after hiking downhill

«Ever since I went on a hike in October that involved a steep descent (around 2 hours), I can’t walk downhill any more without feeling pain in my knees. I have the feeling there is a foreign object pushing into my left knee, on the left side below the kneecap, which nearly blocks the movement, or at least makes it very painful. After a period of rest (e.g. overnight), the pain is gone again. All other kinds of walking don’t cause me any pain, even cycling is not a problem. What could be causing this and what do you suggest I do?»

You strained your kneecap during that downhill hike. Putting a load on your knee joint when it is bent, which primarily occurs when walking downhill or standing up from a chair, can cause the kind of pain you have described. It would be advisable to complete some form of physiotherapy or physical treatment, particularly to strengthen the thigh muscles and lessen the strain on the kneecap. In general, this approach has a good success rate and surgical intervention is not necessary. I would also recommend wearing MBT shoes.
Dr. med. Ulrich Steiger, Endoclinic Zurich, Klinik Hirslanden, Zurich 

Our services for a healthy knees

Health and prevention

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Emergency department and primary care

With a widespread orthopaedic network of hospitals, centres and emergency departments, we are here for you around the clock.

Diagnostics and treatment

In orthopaedics, a diagnosis that is as precise and comprehensive as possible provides the basis for suitable, individual treatment. Learn more about the different diagnosis procedures and the possible conservative and surgical treatments.


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