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Different loss of BMD using uncemented press-fit and whole polyethylene cups fixed with cement : repeated DXA studies in 96 hips randomized to 3 types of fixation . BACKGROUND In cemented THA , aseptic loosening of the cup is more common than loosening of the stem , while periprosthetic osteolysis of the socket resulting in difficult reconstruction problems has emerged as the most significant problem with cementless cup fixation . PATIENTS AND METHODS 90 patients ( 96 hips ) scheduled for THA were stratified in three groups according to the method of fixation of the acetabular component : acrylic bone cement with fluoride ( Cemex-F ) , porous-coated press-fit cup with ceramic coating ( Trilogy , uncemented ) and acrylic cement with gentamicin ( Palacos ) . All patients received the Spectron EF stem . Acetabular bone mineral density was measured with dual-energy X-ray absorptiometry ( DXA ) 1 week postoperatively , and after 12 and 24 months . The periprosthetic BMD was evaluated in 5 ROIs positioned around the acetabular component . RESULTS In the uncemented sockets , the BMD had decreased proximally and medially to the cup after 2 years . The difference was significant in the proximal region as compared to the control group ( Palacos ) . No difference was noted between the 2 groups with cemented components after 2 years . Stepwise linear regression analysis showed that loss of periprosthetic BMD in the proximal high-pressure region after 2 years increased with higher postoperative BMD and when the uncemented design had been used . INTERPRETATION Contrary to previous studies of cemented stems , the use of fluoride cement did not influence the periprosthetic BMD 2 years after the examination . Increased loss of BMD with use of uncemented press-fit cups in the region in which osteolytic lesions are commonly found suggests that stress shielding may initiate the development of this complication . Longer follow-up will , however , be necessary to substantiate this hypothesis .
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Intervention_Surgical
uncemented press-fit and whole polyethylene cups fixed with cement
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Intervention_Surgical
acrylic bone cement with fluoride ( Cemex-F )
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Intervention_Surgical
porous-coated press-fit cup with ceramic coating ( Trilogy
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Intervention_Surgical
acrylic cement with gentamicin ( Palacos )
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Intervention_Surgical
Spectron EF stem
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Intervention_Control
control group ( Palacos
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Intervention_Surgical
fluoride cement
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Outcome_Physical
Different loss of BMD
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Outcome_Physical
Acetabular bone mineral density
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Outcome_Physical
periprosthetic BMD
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Outcome_Physical
BMD
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Outcome_Physical
BMD
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Outcome_Physical
postoperative BMD