Direct comparison of polyethylene wear in cemented and uncemented acetabular cups.
BACKGROUND
It has been indicated that, in the long term, the rate of wear and the degree of osteolysis observed with uncemented acetabular components are greater than those associated with cemented cups, but most studies which compare the wear characteristics of cementless with cemented cups have used historical controls. We report a direct comparison of wear of a cemented and an uncemented cup with similar design, polyethylene, and sterilization method.


METHODS
The study cohort includes 92 patients who were operated in 1997 with primary total hip replacement and have been followed for a period of 9-10 years. All patients were operated by posterolateral approach. In patients 70 years or older we used a cemented cup, in those 60 years or younger we used an uncemented cup, and in patients between 60 and 70 years we used either a cemented or uncemented cup as decided by the surgeon. At follow-up, radiographic imaging was obtained as standard anterioposterior view of the pelvis, and mean wear was determined as described by Livermore et al.


RESULTS
The overall wear of the cemented acetabular components was 1.07 ± 0.78 mm, and that of the uncemented cups was 1.18 ± 0.61 mm (P = 0.529). Wear was significantly associated with male sex (P = 0.003), younger age (P = 0.003), and degree of inclination (P < 0.001), but wear was not significantly associated with cemented versus uncemented cup (P = 0.437).


CONCLUSIONS
Our findings in this 9-10-year follow-up study suggest that cementless cups wear no more than cemented cups of similar design.
Bjerkholt
Håvard
H
Department of Orthopaedic Surgery, Lovisenberg Deaconal Hospital, Oslo, Norway.
Høvik
Oystein
O
Reikerås
Olav
O
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D001843:Bone Cements / Q000494:pharmacology; D002484:Cementation / Q000379:methods*; D015331:Cohort Studies; D016001:Confidence Intervals; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010014:Osteolysis / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D018570:Risk Assessment; D013997:Time Factors
D001843:Bone Cements; D020959:Polyethylene
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