Diseases of the knee joint

Here you will find the most important anatomical basics of a healthy knee joint and an overview of all major knee joint diseases with a short definition of the disease.
For more detailed information just follow the link to the appropriate disease.

Classification of diseases of the knee joint

The following is an overview of the most common diseases of the knee joint ordered by:

  1. Injuries to the ligaments of the knee joint
  2. Injuries to the bony structures of the knee joint
  3. Illnesses due to overloading and wear
  4. Inflammation in the knee
  5. Specific diseases of the knee joint

If you are not sure what your knee pain is causing, we recommend our self-test to find out the cause and treatment options.

Injuries to the ligaments of the knee joint

meniscus damage

A meniscus damage is the injury or tear of one of the two cartilage discs located between the femur and tibial bone. Thigh and tibia do not match with their articular surfaces. To compensate for this "asymmetry" we have "cartilage disks" in the joint, an inner and an outer meniscus.
For more information, see our topic: Meniscus Damage

Anterior cruciate ligament tear

A fresh anterior cruciate ligament tear is the complete or partial continuity break ( tear ) of the ligament after the overstretch reserve has been exceeded by external trauma. An old anterior cruciate ligament rupture is a permanent, usually accidental ligament injury. Typically, such injuries may occur while the calf is down or skiing.

Posterior cruciate ligament tear

A fresh posterior cruciate ligament rupture is the complete or partial continuity discontinuity (tear) of the ligament after exceeding the overexpansion reserve due to external trauma. An old posterior cruciate ligament rupture is the permanent, mostly accidental ligament damage.

Outside ligament

External ligament injuries are usually a tear of the same. Usually the crack is complete - there are hardly any incomplete band breaks. The cause is usually a trauma (rotation, dislocation). Depending on the extent of the injury (outer ligament tear), the therapy is aimed, which can range from the immobilization of several days to the operation. The prognosis is usually good.

Interior ligament

Internal ligament injuries are usually a tear of the same. Usually the crack is complete - there are hardly any incomplete band breaks. The inner band usually tears only as a result of trauma. This can be a kinking, a rotational trauma or a knee joint displacement, as they occur, for example, when skiing or football. The therapy of the inner ligament tear depends on the extent of the injury.

ligament strain

Ligament strain ( syn. Ligament strain) of the knee is caused by a violent movement of the knee joint beyond normal, and may affect both the inner ligament and the outer ligament. It is one of the most common sports injuries and can be caused for example by a sudden rotational movement of the knee.


Patellar tendon rupture is when the tendon tears partially or completely between the anterior thigh muscles and the lower portion of the kneecap. The term patellar tendon rupture is also used synonymously for patellar tendon rupture . Patellar tendon tears usually occur spontaneously due to excessive overstretching of the leg against resistance or when the knee is strained in flexion. Affected people usually express a sudden pain.

Injuries of the bony structures of the knee

Patella fracture

In a patellar fracture breaks the kneecap in several parts. This can create longitudinal, transverse or mixed fractures. The therapy of the patella fracture / patellar fracture depends decisively on the respective fracture form. For further diagnostics, a doctor should be consulted.
For more information, see our topic: Patellar fracture

Shin splints

Tibial nerve syndrome is a chronic pain syndrome in the area of ​​one or more fascial compartments of the lower leg due to sport-related miscarriage between muscle and fascia. The main symptoms of the tibiasus syndrome are primarily pain, initially during movement, later also possible at rest. In the treatment of tibial nerve syndrome, conservative treatment is to be distinguished from surgical treatment.

Shin contusion

Reasons for a tibia bruise are very catchy. Usually, a bone bruise is contracted on the tibia by striking the tibia or striking a rigid or solid object that can not yield. The classic symptoms of tibia bruising are pain, swelling, bruising and some movement restriction.

Illnesses due to overload and wear

Cartilage damage in the knee

Cartilage damage in the knee is quite common. Most of the damage is caused by signs of wear and tear. This wear occurs on the one hand in the context of a very natural aging process. The result of this is called the specialist as osteoarthritis. First of all, it is important that all risk factors are eliminated or reduced as much as possible.

jumper's knee

Jumpers knee is a chronic, painful, degenerative congestion disorder of the patellar extensor at the bony / tendinous junction of the patella. It is also called "patellar tendon syndrome". Patients report stress-related pain in the area of ​​the patella.
For more information, see our topic: Springknee

knee osteoarthritis

Osteoarthritis of the knee joint is understood to mean all degenerative (wear-related) diseases of the knee joint, which are characterized by an increasing destruction of the articular cartilage with involvement of joint structures such as bone, joint capsule and joint-near musculature. It can have several causes and is usually initially characterized by a pain onset, and swelling.
For more information, see our topic: Gonarthrosis / knee joint arthrosis


In typical patellar luxation, the kneecap springs out of the intended slideway to the outside. This often leads to injuries of ligaments, cartilage and bones. The symptoms of knee dislocation are usually so typical that they allow the skilled physician to diagnose the gaze. In most cases, a patellar dislocation does not require any treatment, as it usually springs back into its slide bearing by itself

Shelf Syndrome

The Shelf syndrome occurs after overuse, muscle dysbalance or injury to the knee. It is caused by inflammation and swelling of the mucosal folds (synovial folds, plicae) in the knee joint. This can lead to pain and restricted mobility in the knee joint.
Three mucosal folds of the knee may be affected: the plica suprapatellaris, the plica mediopatellaris and the plica infrapatellaris. By far the most common is plica mediopatellaris .

Inflammation in the knee

Inflammation of the kneecap

Like almost every other organ, the kneecap can also inflame. This can lead to considerable pain and restricted mobility in the knee joint. The main symptom of inflammation of the knee joint is knee pain, especially in the anterior region of the knee joint and above / below the kneecap. The most common cause of inflammation of the patella is overuse.

Inflammation of the patellar tendon

An overuse or overload of the knee can easily lead to irritation and inflammation of the patellar tendon, which is associated with severe knee pain and restricted mobility. Typical are pain at the lower end of the kneecap. The most important measure in the treatment of inflammation of the patellar tendon is the protection.

Inflammation of the quadriceps tendon

In most cases, inflammation of the quadriceps tendon is caused by chronic overstressing of the tendon and all its associated structures. It becomes aware of the affected person above all by a point-like tenderness of pressure exactly over corresponding tendon section. To treat inflammation of the quadriceps tendon, conservative therapy may be considered in the beginning.

Specific diseases of the knee joint

Ahlbäck's disease

The term M. Ahlbäck is understood in the medical jargon as a disease in which it comes to extensive, not caused by an infection death of the bone (aseptic osteonecrosis) in the region of the lower femoral component (femoral condyle). The reasons for the occurrence of M. Ahlbäck are in most cases due to inferior blood flow to the lower thighs.

Sinding-Larsen's disease

The disease known as Sinding-Larsen disease is an extremely painful inflammatory reaction in the knee joint. The majority of affected patients are young people. Sinding-Larsen's disease is increasingly affecting athletes. The treatment of Sinding-Larsen's disease is divided into non-operative and operative measures.


Arthrofibrosis is a dreaded, largely unexplained joint disease after surgery or injury, resulting in a more or less strong, sometimes painful restriction of joint mobility. A distinction is made between primary arthrofibrosis, which is characterized by generalized scarring in the joint, and secondary arthrofibrosis, in which local mechanical irritants are the cause of restricted movement.

Osgood's disease - Schlatter

Osgood-Schlatter's disease is a painful irritation to the approach of the patellar tendon (patellar tendon) on the anterior tibia. This can lead to detachment and death (necrosis) of pieces of bone from the tibia. It creates a dead bone area. Since this osteonecrosis is not infectious (not caused by bacteria, viruses or others, it is included in the group of aseptic osteonecrosis.

Baker's cyst

A Baker cyst is a protuberance of the posterior capsule associated with knee joint disease with chronic knee joint effusion. A baker's cyst is particularly common in the elderly due to wear of the knee joint and in children (usually without a clear cause). The diagnosis of a baker's cyst can generally be made by the doctor.
For more information, see our topic: Baker Cyst

Osteochondritis dissecans

Osteochondrosis dissecans (OD) is a disease that often occurs in growing age and adulthood, affecting about 85% of the knee joint. In the course of this disease, cartilage-related bone death occurs, with a cartilage piece located above the affected bone area being able to detach from its composite.
For more information, see our topic: Osteochondrosis dissecans

Patellofemoral pain syndrome

Pain in the patella is also known as femoropatellar pain syndrome (PFFS). The PFFS is one of the most common complaints in the front knee area. Behind the PFSS hides no uniform clinical picture, but a very complex symptoms, which is discussed in terms of definition, diagnosis and aetiology (causes) very different.

General information about the knee joint

Here you will find more information about the structure and function of the knee joint as well as common symptoms.

The anatomical structure of the knee joint

The anatomy of the healthy knee joint

The knee joint is the largest joint of the human and represents the movable connection between thigh (femur) and lower leg (tibia) dar. Three bones together with a complex capsular and ligamentous apparatus ( side and cruciate ligaments ), the framework of the knee joint.

These are:

  • the femoral rolls ( femoral condyles )
  • the tibial head ( Tibiaplateau )
  • the kneecap ( patella )

Illustration of the knee joint

Figure right knee joint

A - Right knee joint from the left
B - Right knee joint from the front
C - Right knee joint from the back

  1. Patella - patella
  2. Thighbone - femur
  3. Shin - Tibia
  4. Fibula - fibula
  5. Inner meniscus -
    Meniscus medialis
  6. Outer meniscus -
    Lateral meniscus
  7. Patella Ribbon -
    Ligamentum patellae
  8. Outer band -
    Ligamentum collateral fibular
  9. Inner band -
    Ligamentum collateral tibiale
  10. Posterior cruciate ligament -
    Ligamentum cruciatum posterius
  11. Anterior cruciate ligament -
    Ligamentum cruciatum anterius

The illustration above shows that the bones are in close contact with each other. So that a pain-free and undisturbed mobility of the knee joint can also take place at the contact surfaces, the bones at the respective contact surfaces are coated with a very smooth, whitish cartilage layer, the so-called hyaline cartilage.
Only through them is a painless and undisturbed mobility of the knee joint possible. The hyaline cartilage is composed of cartilage cells and matrix tissue. While the cartilage cells of the adult have lost the ability to divide and thus heal, cartilage wounds can be repaired by proliferation of cartilaginous cartilage cells.
The cartilage cells are embedded in the matrix tissue they produce themselves. This consists largely of water and supporting tissue and gives the cartilage tissue both stability and elasticity.

In the knee joint itself, a distinction is made between the joint of the femur and the kneecap ( femoropatellar joint ) as well as the femoral roll and the tibial bone. The connection between the femoral roll and the patella is the most heavily loaded part of the knee joint. When climbing stairs, this joint is burdened, for example, with more than three times the body weight.

The most important tendon of the knee joint is the patellar tendon (patellar tendon), which pulls from the kneecap at the front of the knee as a strong strand to the tibia ( tuberosity tibiae ).

The knee joint is surrounded by the knee joint capsule, whose inner part is called the synovium. It forms the synovial fluid important for the nutrition of the cartilage. In adulthood, the cartilage tissue is mainly fed by diffusion (passive transport) from the synovial fluid, because cartilage tissue, in contrast to other types of tissue of the body (muscles, bone skin, etc.) is not supplied with blood.

The usual diet on the bloodstream does not work therefore.
Movements of the knee joint mix the synovial fluid and thereby improve the uptake of nutrients through the cartilage cell ( chondrocyte ).
The correct amount and composition of the synovial fluid is also crucial for the lubrication of the knee joint. They minimize the friction of the corresponding cartilage surfaces during movement. Hyaline cartilage has an extremely low frictional resistance, lower than any known artificial material pairings.

Between the femoral roll and the lower leg there are two fibrocartilage discs (meniscus), which serve as a buffer between the cartilage surfaces and are important for an even pressure distribution in the knee joint under load. The cruciate ligaments pass through the knee joint and connect the thigh to the lower leg. The main task of the cruciate ligaments is to ensure a stable knee joint and thus to enable a harmonious, smooth, low-friction movement.
The two cruciate ligaments prevent the knee from shifting to the front (anterior cruciate ligament) or posterior (posterior cruciate ligament) when loaded. In their stabilizing effect, they are supported by the lateral ligaments (collateral ligaments), the knee joint capsule and the knee-spanning muscles.

The knee-spanning muscles make up the function of the knee joint. Only through them does movement become possible. In addition, they support the passive joint stabilizers of the capsular ligament apparatus. The extensor muscles of the knee joint (quadriceps muscles) on the front of the thigh are very strong. Involuntarily, the muscles are activated when the knee joint flexes to avoid buckling when walking. The most important flexors of the knee joint are the hamstrings on the back of the thigh, which also has an active stabilizing effect on the knee joint. The ischiukrurale musculature supports in particular the anterior cruciate ligament, which is why their training after a cruciate ligament rupture is particularly important.

knee pain

Knee pain can be subdivided depending on where in the knee they occur.
Knee pain on the inside may indicate a lesion of the inner meniscus or inner ligament. In addition, they often occur in the context of signs of wear, for example in a knee joint arthrosis on the inside of the knee joint. Improper loading when walking through inappropriate footwear, misalignment of the feet or leg axis, and a leg length difference can cause pain on the inside of the knee.

The same applies to the outside of the knee joint. Localized pain ( see : external knee pain), in contrast to the pain on the inside, rather indicates involvement of the outer ligament or the outer meniscus.
Knee joint arthrosis may also be the cause if it affects the outer knee joint area. In acute injuries of the menisci or ligaments, the pain is usually stinging, occurring suddenly and often accompanied by other symptoms such as swelling or overheating of the joint region and an articular effusion.
In degenerative processes, such as osteoarthritis, the pain usually develops over a longer period of time and occurs mostly when the joint is stressed.

Knee pain, which mainly focuses on the popliteal fossa ( see: popliteal pain), can also have different causes. Pain in the popliteal fossa may occur if the back of a meniscus is injured. Also, an inflammation or change of muscle tendons and a knee joint arthrosis in this area can explain the symptoms.
Osteoarthritis or meniscal damage in the joint can eventually lead to the development of a so-called Baker's cyst. This is a bulge of the joint capsule, which is filled with liquid. The Baker cyst can be felt from a certain size as swelling in the popliteal fossa and can also cause pain there.
For pain in the popliteal fossa must always be thought of a thrombosis - ie a blood clot - in the blood vessels of the lower leg.

Knee pain can also be localized behind the kneecap. This is typical of so-called retropatellar arthrosis, an arthrosis that develops directly behind the patella . Also, a muscular imbalance or congenital deformity of the kneecap can cause pain behind the patella, as this then can not slide in the intended for her bone gullet. It comes to friction and wear in the joint and secondarily to pain.

Figure knee pain on the inside

Picture knee pain in

A - Right knee joint from the front

  1. Inner thigh muscle -
    Musculus vastus medialis
  2. Thigh bone -
  3. Kneecap -
  4. Inner meniscus -
    Meniscus medialis
  5. Inner band -
    Ligamentum collateral tibiale
  6. Internal calf muscle
    Gastrocnemius muscle,
    Caput mediale
  7. Shin -
    a - Internal ligament injury
    (Inner ligament)
    b - inner meniscus tear
    c - medial
    (internal) knee osteoarthritis

Figure knee pain on the outside

Figure knee pain outside

A - Right knee joint from the front

  1. Outer thigh muscle -
    Musculus vastus lateralis
  2. Thigh bone -
  3. Kneecap -
  4. Outer meniscus -
    Lateral meniscus
  5. Outer band -
    Ligamentum collateral fibular
  6. Fibula -
  7. Shin -
  8. Outer calf muscle
    Gastrocnemius muscle,
    Caput lateral
    a - External ligament injury
    (Outer ligament)
    b - External meniscus tear
    c - Lateral
    (Outer) knee joint osteoarthritis

Tap the knee

To stabilize the knee, tap it with special ribbons.
These so-called kinesi tapes can be used in many ways and achieve a good effect. However, in order for the knee to be optimally relieved and stabilized, the right technique for taping is indispensable.

For this purpose, a Y-shaped incised tape is glued above the patella and then the two Y-legs outside and inside led around the patella so that they meet again below the kneecap. When sticking the knee should be bent. As an alternative to the Y-shaped cut of the tape, two individual tape strips can be wrapped around the outside of the kneecap in an arc shape on the outside and inside.
When adhering below the kneecap, no tension should be exerted on the tape. If the leg is now stretched out, the skin should wrinkle over the knees. The patella is then optimally stabilized in position and dislocation during exercise is prevented.

Knee twisted

A twisted knee causes severe pain immediately after the trauma.
The unnatural dislocation overstretches the ligaments in the joint area. Blood vessels can rupture and bruising in the skin and articular effusions may form.

This often manifests itself by a swelling of the joint. The joint capsule can also be damaged during the rotation. The exact extent of the injury can usually not be recognized by the clinical picture alone. This requires more precise diagnostic measures.
As an acute therapy of the twisted knee joint, it is advisable to raise and cool to prevent further swelling.
If there are no further injuries in or on the joint beyond the strain, no special therapy is necessary. The pain usually lapses within a few days.

Painkillers can be used to bridge the gap, as the twisted knee can still cause pain for a long time under stress. If ligaments or capsule have been damaged more, a more detailed diagnosis must be made.
In a twisted knee with swelling and / or instability, the diagnosis is usually done via an MRI from the knee. In knee MRI, soft tissue damage, as occurs especially on the capsule and ligaments, can be detected particularly well.

Many more information on what you can do and should see our topic: Knee twisted

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Stages of Knee Osteoarthritis (February 2020).

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