Forms

Since the knee joint is composed of three sections, different forms of gonarthrosis are distinguished depending on their localization. Each group can be affected individually or together with the others. One group represents the femoropatellar joint, i.e. the joint surface between the thigh bone (femur) and the kneecap (patella).

Retropatellar arthrosis occurring in this area manifests itself mainly in sitting, when climbing stairs or in the transition from squatting to standing with pain. The joint between the femur and tibia (femorotibial joint) can be divided into two further groups. A distinction is made between medial gonarthrosis, i.e. the inner side of the femorotibial joint, and lateral gonarthrosis (outer side).

If all three areas are affected by the arthrosis, it is called pangon arthrosis. If the lateral gonarthrosis occurs with a x-leg malposition (valgus), it is called valgus gonarthrosis. Varus gonarthrosis summarizes medial gonarthrosis with bowleg malposition (varus).

Here, the arthrosis is of a secondary nature and is promoted by the uneven strain on the knee joint resulting from the malposition. Pain in the knee joint can have various causes. First, the doctor will make a tentative diagnosis by talking to the patient and carefully examining the characteristics of the pain.

This diagnosis will be confirmed in the course of the clinical examination. During the examination, the doctor will pay attention to the appearance of the legs and knees. The leg axes, musculature and gait pattern are particularly important.

The shape of the knee can also be used to determine whether there is any swelling or the like. The physician then manually examines the knee and checks whether there is any swelling due to an effusion, checks mobility and tests whether crepitation can be heard when the knee joint is moved. Some specific tests enable the examiner to determine whether gonarthrosis is responsible for the pain.

However, imaging techniques are also part of the diagnostic process. Above all, x-rays of the knee joint are a quick and inexpensive way to diagnose osteoarthritis. The knee is imaged in two planes, which can be supplemented by special images if necessary.

The x-ray image can show signs typical of osteoarthritis. These include the narrowing of the joint space, which is the first visible sign of arthrosis in radiological images. As a result of the increasing load on the bone in the case of arthrosis, the bone is strengthened, so to speak, and the bone tissue becomes denser (subchondral sclerotherapy) under the former or remaining cartilage layer of the joint.

In the course of the bone changes, new bone tissue is also formed, especially in the marginal area of the joint; this is called osteophytic marginal tissue. In advanced stages of osteoarthritis, cysts of debris form. These cysts are caused by the undamped contact of the bone surfaces in osteoarthritis.

The resulting small traumas trigger the death of small regions in the bone. These regions show up in the X-ray image as recesses in the bone. In summary, the X-rays provide a very good overview of the processes in the joint. The ultrasound examination can mainly detect knee joint effusion. Other possible examinations are computer tomography, magnetic resonance imaging or skeletal scintigraphy.