A randomised, controlled clinical study on total hip arthroplasty using 4 different bearings: results after 10 years.
OBJECTIVE
To compare 4 different bearings in total hip arthroplasty (THA) in a randomised controlled clinical study on clinical performance.


METHODS
393 patients with osteoarthritis of the hip or avascular necrosis were included and allocated to 1 of the head-and-cup couples zirconia-on-polyethylene (group A), metal-on-metal (group B), zirconia-on-polyethylene with the liner moulded into the shell (group C), or alumina-on-alumina (group D). In the individual case the surgeon could choose other implants if indicated.


RESULTS
299 patients were operated with the allocated prosthesis. The estimated cumulated prosthesis survival percentages and 95% confidence interval after 10 years were: group A 84.6 (75.8-93.4); group B 95.0 (89.5-100); group C 93.2 (86.7-99.7); group D 66.1 (54.5-77.7). The patients' physical function was significantly improved and remained equally good in all 4 groups, however slightly declining with ageing. The luxation rate was initially high, and equal between the groups, but was reduced by improving the surgical procedure introducing capsule repair by reinsertion of the short external hip rotators.


CONCLUSIONS
The metal-on-metal or zirconia-on-polyethylene prostheses had high 10-year survival percentages. The longevity of these bearing couples by themselves was not related to the combination of materials. The zirconia-on-polyethylene prosthesis with the liner mounted peroperatively possibly exhibited cases of backside wear which the corresponding bearing couple with moulded polyethylene (Asian) did not. The alumina-on-alumina bearing performed poorly - it was redesigned after our study initiation and later withdrawn from the market.
 Department of Orthopaedic Surgery, Bispebjerg and Frederiksberg University Hospital, Frederiksberg - Denmark.
Arne
A
Borgwardt
 Department of Clinical Physiology and Nuclear Medicine, Herlev University Hospital, Herlev - Denmark.
Bo
B
Zerahn
 Department of Orthopaedic Surgery, Bispebjerg and Frederiksberg University Hospital, Frederiksberg - Denmark.
Sandra D
SD
Fabricius
 Department of Orthopaedic Surgery, Bispebjerg and Frederiksberg University Hospital, Frederiksberg - Denmark.
Tine H
TH
Bertelsen
 Department of Orthopaedic Surgery, Bispebjerg and Frederiksberg University Hospital, Frederiksberg - Denmark.
Henrik
H
Daugaard
 Department of Orthopaedic Surgery, Bispebjerg and Frederiksberg University Hospital, Frederiksberg - Denmark.
Søren
S
Ribel-Madsen
D000368:Aged; D000537:Aluminum Oxide / Q000737:chemistry; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods; D002858:Chromium Alloys / Q000737:chemistry; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000601:surgery*; D011379:Prognosis; D011474:Prosthesis Design / Q000379:methods*; D011475:Prosthesis Failure; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome; D015040:Zirconium / Q000737:chemistry
D002858:Chromium Alloys; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide