[Osteointegration of porous tantalum stems implanted in avascular necrosis of the hip].

Efficacy of osteointegration of tantalum porous systems has been demonstrated through animal experimentation. However, there is a lack of studies that evaluate osteointegration of implants retrieved after a period of implantation in humans. For this study, eight rod implants used for the treatment of avascular necrosis of the femoral head were retrieved following collapse of the femoral head and conversion to total hip arthroplasty. The time of implantation ranged between six weeks and twenty three months. Observation during this study has confirmed effectiveness of osseointegration within this period of time. New bone was observed around and within the porous system of the on rod devices at retrieval date. Bone in growth however, proved to be of a slower and less intense degree than that resulting within animal species during first months after implantation. Nevertheless, the results obtained in the quantitative evaluation of this process proved to be similar to those results achieved by other authors in previous experimental studies.