Osteoarthritis (OA)

What is OA?

Osteoarthritis of the knee joint is characterized by wear of the cartilage and associated synovitis. It is the most common joint disease and also called degenerative joint disease.


The patient suffering from OA of the knee complains about pain, limited range of motion, hyperthermia and swelling.The knee feels rusty and stiff, in particular in the morning. The pain increases with activity and sports. Here especially all high impact sports such as tennis, jogging, handball, soccer or other team sports are painful.

In the final stage sports and even walking is not possible even with pain killers.

From the healthy and happy knee joint to osteoarthritis....


On can distinguish between a varus (bowed leg) type OA from a valgus (x-shaped leg) and a all compartments affecting OA.

In the varus type OA the mechanical leg axis runs through the medial compartment, which then results in chronic overloading and OA of the medial compartment.

In the valgus type OA the mechanical leg axis runs through the lateral knee compartment, which then leads to chronic overloading and OA of the lateral compartment.

The patellofemoral joint as third compartment can also be affected.

When all knee compartments are affected by OA, it is called a complete OA of the knee joint.

Causes of OA

The cause of OA is multifactorial.


Mechanical overloading of the medial (bow-shaped leg axis) and lateral (x-shaped leg axis) joint compartment have been identified as causes for OA.


Another frequent cause for OA is a previous trauma to the knee joint (posttraumtic OA).


In a considerable number of patients the cause of OA remains unclear.


More information on OA can be found here: