Polimers are being used as biomaterials for quite a long time now in broad fields of use in orthopedic surgery. Bioabsorbable polymers have a very important advantage of not requiring an implant removal surgery after fracture union is obtained. The human body absorbs these materials in time. However, these materials still do not provide a bone fixation as reliable as with the metal materials. Because of this weakness, they are preferred for fixation of small, non-weight bearing bones such as malleolus, condyle, metacarpal bones and phalanx. Besides the weakness of fixation, sterile sinus formation they cause in the surgical area represents the second problem with these materials. Ultra high molecular weight polyethylene is the most important plastic polymer that is being used for a very long time in weight bearing parts of the joint prostheses bearing surfaces. The sterilization method is important due to its effect on the physical and chemical properties of this material. Sterilization with gamma radiation under vacuum is the most accepted technique. Osteolysis between bone and stem caused by polyethylene wear debris and the resulting pain represents one of the most important problems with these materials.