Knee pain (synonyms: Gonalgia; ICD-10-GM M25.56: Joint pain, lower leg, knee joint) in the knee joint area is usually due to functional or morphologic changes:
- Bony & cartilaginous compartment (femoral condyles/femoral rolls, tibial head/tibial head, fibular head/calf head, patella/patella).
- Ligamentous apparatus (anterior and posterior cruciate ligaments/ligamenta cruciata genus, medial and lateral collateral ligaments/lateral collateral ligament, patellar tendon/ligamentum patellae).
- Inner and outer meniscus
- Synovia (“synovial fluid”)
- Periarticular tendon and muscle apparatus, bursa.
- Connective tissue and skin
The knee joint is the largest joint in the human body and is particularly stressed.
Gonalgia describes a painful knee (knee pain); gonarthralgia describes a painful knee joint (knee joint pain).
The following forms of gonalgia are distinguished:
- Start-up pain – manifested at the onset of activity; typical in degenerative joint disease.
- Night pain or pain at rest – especially in inflammatory diseases of the joints or when overloaded degeneratively altered joints.
- Strain pain – only when the respective joint is loaded, at rest no pain is felt; in traumatic lesions of a joint, inflammatory or degenerative changes.
Knee pain can occur acutely or be chronic.
Knee pain can be a symptom of many conditions (see under “Differential Diagnoses” [knee joint pain in different age groups]). The most common cause of knee joint pain – especially in older patients – is gonarthrosis (osteoarthritis of the knee joint).
Frequency peak: With increasing age, the number of people affected by knee pain also increases. Here, the cause is usually a degenerative (wear-related) joint disease. Younger people also suffer from knee pain. This is then usually due to trauma (e.g. sports injuries).
The prevalence (disease frequency) of working people for knee pain is given as 54% (Germany).According to a study by the Robert Koch Institute, 17.3% of women and 15.1% of men in Germany stated that they had experienced knee pain within the past 12 months.
Course and prognosis: If knee pain is recurrent (recurring) or sudden and massive, a doctor should be consulted. The prognosis depends on the underlying condition and is more effective the sooner a painful knee is treated.When adolescents complain of knee pain, it was still present in one in two after two years, according to a Danish study. Often, the pain was persistent patellofemoral pain (PFS; patellofemoral pain syndrome; anterior knee pain, anterior knee pain). Patellofemoral pain syndrome affects the joint between the thigh bone (os femoris, or the femur for short) and the kneecap (patella; kneecap joint) and refers to pain that occurs between the two bones (esp. in the lateral region). The pain is associated with a risk of chronicity that was 26% higher than for knee pain of other locations. Note: In children and adolescents with knee pain, it is essential to also consider diseases of the hip or pelvis!Possible causes of knee pain are esp. meniscus lesions (meniscus injuries), tendinopathies (diseases of the tendons/s. u. “Enthesopathies (lower extremity excl. foot”) or bursitis (inflammation of the bursa).
