The joint consists of the hip socket (acetabulum) as part of the pelvis and the hip joint head (femoral head) as part of the thighbone. Both joint parts are covered in a sliding cartilaginous layer.

The joint capsule seals the joint and produces joint fluid for the alimentation of the cartilage and enables smooth movement.

The most frequent cause of hip joint illness is the wear of the joint cartilage (hip arthrosis, coxarthrosis). In addition, the replacement of the hip joint can be necessary due to rheumatism, an innate erroneous trend of the joint, a break in the femoral neck, or in the context of arthritis caused by an accident. The wear it exerts on the cartilage leads to the progressive destruction of the hip socket and the femoral head.

The joint becomes increasingly more painful, putting weight on it is painful and the feasible walking distance is reduced. Eventually there comes a point where resting provides no relief from the pain.

The evaluation of the extent to which arthrosis has affected the hip and the subsequent operational planning are done using a radiograph, or X-Ray. The interference is totally pain free both under full anaesthetic and under spinal-cord anaesthesia and lasts between 50-120 minutes.  In the operating room, firstly the joint is opened. The joint cap, bone deformities and destroyed femoral head are removed. Subsequently, a metal or polyethylene hip cup is used. The metal cup also includes an inlay made of ceramic or plastic. In order to anchor the hip stem, the thigh bone is reamed. The hip stem is anchored in the created bone space and is either cemented or cementless. A metal or ceramic head is subsequently put on the stem, and the tension is then examined, as well as the mobility of the new joint. Afterwards, the tissue is closed and a drain for the wound secretions is inserted, which is removed 2-4 days later. The skin stitches or staples are removed after 12 to 14 days.

Apart from the general operation risks such as bleeding, postoperative haemorrhaging and infection, there are also special complications that can occur during and after the operation. In addition, as with most meticulous surgical techniques the risk of damage to large blood vessels and nerves must not be ignored. The endoprostheses can loosen in the process, the leg length can differ, and in very rare cases there is also the possibility of dislocation. Sometimes blood transfusions can be a necessity. Usually however, blood salvaging surgical techniques and systems are implemented for re-infusion (Cellsaver method). Any lost blood is collected, cleaned and returned to the patient after the operation. In this way, foreign blood transfusions, and thus the dangers of becoming infected with hepatitis or HIV (AIDS) can be significantly decreased. For the patients who initially cannot be fully mobilized after an operation, a greater risk of deep vein thrombosis (DVT) exists. This danger is reduced with the implementation of patient physiotherapy, as well as with the regulation of antithrombotic stockings and blood-thinning medication.