During prosthesis implantation, the surgeon can choose from replacements of a wide variety of manufacturers and sizes. So far, no specific coefficient has been introduced that determines the suitability, or goodness of these prostheses. In this paper an apparatus is presented for the qualification of knee prostheses. This apparatus is able to measure the rotation of any prosthesis, therefore the obtained results can be compared with the measured values on human cadaver knees. The prostheses are classified by the rate of their conformity. In addition, the first experimental results are reported as well.

The necessity for the knee prosthesis is confirmed by the large increase in the number of patients suffering from arthrosis, which is a present-day disease. Despite this need, there doesn’t exist an optimal knee prosthesis. Nowadays the development of the knee prostheses is progressing. It is very difficult to define the required geometry with traditional methods, because the movement conditions to be created by the prostheses should be similar to the movements of the human knee. During previous research the biomechanical research team of the Szent István University occupied with experimental measurements of the healthy human knee joint movement. In this paper I would like to introduce a method of prosthesis geometry development. As a result, a knee prosthesis geometry has been created which is approaching the movement form of the real human knee joint.

The necessity of the knee prosthesis confirmed by the large increase in the number of patients suffering from arthrosis, which is a present-day disease. Despite of the need doesn't exist optimal knee prosthesis. Nowadays the development of the knee prostheses are takes place. It is very difficult to define the geometry with traditional methods, because the movement conditions that created by the prostheses should be similar of the movements of the human knee. During previous researches the biomechanical research team of the Szent Istvan University is defined with experimental measurements the healthy human knee joint movement. In this paper I would like to introduce a method of prosthesis geometry development. As a result a knee prosthesis geometry was created which is approaching the movement form of the real human knee joint.

AbsztraktA jelen tanulmány azt a kérdéskört vizsgálja, hogy a teljes felszínpótló térdprotézisek beültetése során alkalmazott beültetési protokoll jellemzői miként vannak hatással a létrejövő új ízületi kinematikára. A protézis beültetések száma egyre nő, azonban az operáló orvos csak a gyártót és a méretet választhatja meg a gyártó által ajánlott protokollal. A jó protézis elvárt tulajdonsága, hogy jól beépíthető és tartós legyen, illetve javítsa a páciens életminőségét az által, hogy megfelelő rotációt biztosít a térd behajlítása során. Ennek eredményeként a protézis által létrehozott mozgás mindinkább megfeleljen a térd természetes kinematikájának. Az operáló orvos számára a protézis beültetési protokoll az egyes beültetési szögbeállításokra (a továbbiakban faktorokra) tartományo-kat, adott esetben javasolt értékeket ajánl. E beültetési tényezők rotációra gyakorolt együttes hatá-sát mérjük fel és keressük az optimális beültetési értékeket annak érdekében, hogy a rotáció-flexió mozgás mindinkább közelítse az ízület valós mozgását. Kulcsszavak: biomechanika, térd, protézis Effects of TKR implantation methods on the kinematics of the knee joint AbstractThe following study examines the issues that how the implanting protocol's features of TKR knee prosthesis affect the new knee kinematics. The number of implanted prostheses are increasing, but surgeons can only chose the manufacturer and the size of the prostheses with the recommended implanting protocol. From a good prosthesis it is required to be well implantable and durable, on the other side it should improve the patient's quality of life by ensuring the required knee rotation during the flexion movement. The movement, which is allowed by the knee prosthesis, should meet even more the human knee movement. For the surgeon the prosthesis implanting protocol offers angle ranges (further factors) or optionally recommended values to each implanting factors. Our aim is evaluate the common effect of the implanting factors to the rotation, and we are trying to determine the optimal implanting factors to the rotation-flexion movement that should approach the original movement of the knee joint.

The biomechanics is a relatively new topic; it describes the behaviour of living organisms which is developed by the synergy of biology and mechanics. The Biomechanical Research Team of the Szent István University is working for a long time with the human knee joint which is the most complex joint of the human body. The research team designed an experimental apparatus for the measurement of cadaver knee movements. The designing of new generation of prosthesis is based on the measurements made on the apparatus. A new part was designed to the experimental apparatus to make it suitable for testing and qualifying the new prosthesis. Hereby we made the apparatus suitable for knee prosthesis movement measurement and for qualification as well. Under the prosthesis certification process we compare the results with the rotation -flexion and force graphs which are measured on the cadaver knee. We make the prosthesis movement the help of a stepper motor, because it allows us to measure in the whole flexion range (120°).