[Surface structures and bone ingrowth in cement-free fixed prostheses]

Non-cemented implants are used primarily for hip and knee arthroplasties. Bone ingrowth into porous surfaces of different materials is required. Criteria of long-term success are primary stable fixation and the achievement of intimate bone contact by press-fit. However, animal experiments show that interdigitation with porous coating induces osteoporosis of the surrounding cortex. It appears that bony fixation gives rise to fewer problems in the acetabulum than in the femur. The results of animal experiments and follow-up studies in humans are used to compare potential problems of fixation without cement with the results obtained with bone cement.