FIXATION OF THE ACETABULAR COMPONENT - THE CASE FOR CEMENT

The long term success rate of cemented sockets in total hip arthroplas ty has been well documented in patients who are 60 years of age and ol der and who have had a followup of as many as 16 years, The failures w ith cemented sockets have been observed in young patients, patients wi th poor bone stock (rheumatoid and dysplastic hips) with metal backed components, and in revision surgery with loss of acetabular bone, Rana wat et al have shown that most mechanical failures of cemented socket fixation within 10 years of primary operation is attributable to failu re to achieve a good fixation initially of the cement and bone, Volume tric wear of the polyethylene of a cemented socket against a 22- or 28 -mm femoral head is compared with the metal backed cemented and noncem ented cups, The increase in volumetric polyethylene particles with met al backed cemented sockets and noncemented sockets will induce histioc ytic response, The mechanism of histiocytic invasion should be similar for cemented all polyethylene sockets and noncemented sockets, It man ifests itself in the cemented socket as global radiolucency when the s ocket is loose and as osteolysis when it is well fixed for noncemented and cemented sockets, If the number of particles coming out in a nonc emented and hybrid total hip replacement are greater, osteolysis would be expected to increase with longer followup, The technique of cement ed polyethylene sockets requires organization of the surgical team and hypotensive epidural anesthesia, Under these conditions the procedure is very reproducible, As far as cost is concerned, the all polyethyle ne socket is significantly less expensive, It seems that cemented tota l hip replacement is most suitable and perhaps is the right kind of op eration for treating osteoarthritis of the hip for patients who are 60 years of age and older because the procedure is reproducible, the qua lity of arthroplasty is excellent, and it is durable, lasting as many as 15 years in 90% to 95% of the cases.