Knee pain

The knee joint represents the largest joint in the human body. This joint is made up of the femur, tibia and patella, the inner and outer meniscus, as well as the cruciate ligaments, collateral ligaments, patellar ligament as well as the joint capsule. In addition, there are several bursae that provide smooth gliding of the tendons and the so-called Hoffa fat pad for cushioning the patella and patellar ligament.

These structures can all be impacted by trauma (injury), inflammation, or degenerative processes, causing painful sensations ranging from load-dependent mild pain to severe pain-induced restricted range of motion. Knee pain can be treated with physical measures, medication or surgery, all depending on the cause and severity of symptoms. 

What are common causes of knee pain?

Among the most common causes of knee pain, particularly in individuals who are active in sports or physical labor, is functional pain from overuse. Children and adolescents often experience growing pains in the knee area.

Further potential causes can be divided into three groups.

Traumatic knee pain

This type of knee pain is brought on by an injury and usually begins suddenly at the moment of the injury. This group includes:

• Strained or torn ligaments

• Contusion (injury of connective tissue and small vessels by blunt force, such as a fall or blow) 

• Meniscus injury 

• Dislocation (displacement of the bones of a joint against one another. Especially the kneecap is often affected).

• Fracture (broken bone) 

Knee pain caused by inflammation 

A number of conditions can result in an inflammatory response in the knee. Mild, short-term inflammatory reactions are harmless, however, severe and chronic inflammation can progressively destroy the knee joint. The triggering pathologies include, for example:

• Tendinitis, or inflammation of the tendon insertion (mostly due to incorrect or excessive strain; for the knee joint, the pes anserinus syndrome in particular, which affects several tendon insertions on the inner aspect of the shinbone).

• Bursitis (e.g. due to incorrect or excessive loading, but also as part of other inflammatory processes) 

• Bacterial arthritis or reactive arthritis caused by infections in the gastrointestinal or urogenital tract 

• Autoimmune diseaseslike rheumatic diseases or psoriasis 

• Gout 

Degenerative knee pain 

Osteoarthritis is a degenerative disease and a common cause of knee pain, in particular in older age. However, it can also affect younger people, especially in the case of past trauma or years of heavy (incorrect) loading.  

It involves a slowly advancing process related to age, which is generally of a non-inflammatory nature but can be worsened by additional inflammation (activated osteoarthritis) and leads to gradual destruction of joint cartilage and more joint structures. 

Typical symptoms of knee injuries or wear and tear

Knee joint injuries can give rise to bruising or external bleeding, redness, swelling as well as pain and swelling which restrict movement. Upon visual inspection, the shape of the knee joint and leg may be changed due to fractures or dislocations. If a fracture occurs, the skin may also be visibly pierced and there may be palpable crepitations (friction of bone fragments). 

Inflammatory diseases are mostly characterized by pain, redness, swelling, warmth and functional limitations. 

Such symptoms of inflammation are only present in degenerative knee pain in the case of activated arthritis. Aside from load-dependent pain, the main symptoms here are limited range of motion and a sense of instability.

How do knee specialists diagnose knee pain?

The diagnosis of knee pain starts with a medical history. Questions address the location, duration and dynamics of the pain, potential injuries, exertion, prior illnesses and accompanying symptoms. In most cases, a comprehensive medical history allows a rough classification of the underlying disease.

Next, the knee joint is inspected and palpated and compared with the other knee. Should there be any suspicion, other tests can be run.

Joint effusions, such as those related to rheumatic diseases, can be detected by an ultrasound examination. If a fracture is suspected, an x-ray examination is performed, whereas soft tissue injuries, like torn ligaments or damage to the meniscus, as well as degenerative changes are best diagnosed with an MRI examination.

A laboratory assessment of certain blood values may also be included. For instance, if there is concern about an inflammatory cause, a number of inflammatory parameters and rheumatoid factors are tested for, and if gout is suspected, uric acid levels are analyzed.

In case of a potential bacterial arthritis, a puncture of the knee joint has to be made with a sterile needle for microbiological examination of the joint fluid and targeted treatment of the germs. Without treatment, joint infections can rapidly result in a destruction of the knee joint.

If non-invasive diagnostics yield no results, arthroscopy, meaning that a small camera and potential instruments are guided into the knee joint, may be necessary. This can visualize damage which could not be shown by imaging. Samples can be taken and, if necessary, treatment can be provided under arthroscopy in one sitting. 

How can knee pain be treated?

Various treatments are needed for knee pain, depending on the cause.

Rest 

Particularly for functional pain due to overuse, as well as for acute injuries or during phases of high inflammatory activity, like bacterial arthritis, an acute rheumatic flare-up or a gout attack, it is important to rest the affected joint, as stress can worsen the pain and possibly damage the joint. With chronic diseases like rheumatoid arthritis, however, long-term rest is actually contrary to the goal. Moderate exercise in phases with low disease activity is recommended.

Physical therapy

Measures of physical therapy such as applying heat, cold or electricity, as well as massages, can provide relief for most forms of knee pain. For acute injuries, the knee should be cooled to reduce swelling, which would lead to more pain.

Medication 

On the one hand, pain killers can be administered to relieve the symptoms of knee pain. For example, for growth pain or mild degenerative changes, painkillers are usually enough. 

On the other hand, some underlying diseases which trigger knee pain can be treated with medication. Examples include rheumatic diseases, gout or bacterial arthritis.

Surgical treatment

Knee injuries in particular may sometimes require surgical treatment, for example by repairing a ligament or meniscus or repositioning and fixing a dislocated broken bone.

Even in the case of bacterial arthritis, surgical repair is recommended due to the dangerous nature of the disease.

In cases of severe destruction of the knee joint as a result of osteoarthritis or a rheumatic disease, the joint can be partially or completely replaced by a joint prosthesis, which will usually improve both pain and functional restrictions significantly.

Can you prevent knee pain?

Any person can be suffering from one of the many causes of knee pain. But there are a few things you can do to avoid some of the underlying conditions. 

Maintaining a normal body weight will ensure that your knees are not subjected to additional weight during daily movements. While exercising and stretching the leg muscles stabilize the knee and physical activity is essential for normal joint function, some sports, like swimming or cycling, are gentle on the joints, whereas others, such as football, carry a higher risk of excessive strain or injury to the knee joint owing to sudden movements. Prolonged sitting and in particular prolonged kneeling should be avoided.

Which doctors and clinics specialize in knee pain?

For most causes of knee pain, orthopedists and trauma surgeons are the appropriate specialists. While in the past they used to be two distinct specializations, nowadays they form part of one residency.

If pain is due to diseases that fall within the spectrum of internal medicine, for example rheumatic diseases or gout, they are treated by an internal medicine practice or clinic.

If you're in need of a doctor, you expect the best medical care possible. So of course patients are curious to find out what clinic to go to. As there is no objective way to answer this question and a legitimate doctor would never claim to be the best, patients must rely on a doctor's experience.

Let us help you find an expert for your condition. All listed doctors and clinics have been reviewed by us for their outstanding specialization in the field of knee pain and are looking forward to your inquiry or wish for treatment.

Sources:  

• Wolfgang Miehle: Rheumatologie in Praxis und Klinik. Georg Thieme Verlag 2000, ISBN: 978-3-137-01102-6 

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