Short-term survival of the trabecular metal cup is similar to that of standard cups used in acetabular revision surgery.
OBJECTIVE
The use of trabecular metal (TM) cups in revision surgery has increased worldwide during the last decade. Since the introduction of the TM cup in Sweden in 2006, this design has gradually replaced other uncemented designs used in Sweden. According to data from the Swedish Hip Arthroplasty Register (SHAR) in 2012, one-third of all uncemented first-time cup revisions were performed using a TM cup. We compared the risk of reoperation and re-revision for TM cups and the 2 other most frequently used cup designs in acetabular revisions reported to the SHAR. The hypothesis was that the performance of TM cups is as good as that of established designs in the short term.


METHODS
The study population consisted of 2,384 patients who underwent 2,460 revisions during the period 2006 through 2012. The most commonly used cup designs were the press-fit porous-coated cup (n = 870), the trabecular metal cup (n = 805), and the cemented all-polyethylene cup (n = 785). 54% of the patients were female, and the median age at index revision was 72 (19-95) years. Reoperation was defined as a second surgical intervention, and re-revision-meaning exchange or removal of the cup-was used as endpoint. The mean follow-up time was 3.3 (0-7) years.


RESULTS
There were 215 reoperations, 132 of which were re-revisions. The unadjusted and adjusted risk of reoperation or re-revision was not significantly different for the TM cup and the other 2 cup designs.


CONCLUSIONS
Our data support continued use of TM cups in acetabular revisions. Further follow-up is necessary to determine whether trabecular metal cups can reduce the re-revision rate in the long term, compared to the less costly porous press-fit and cemented designs.
Department of Orthopedics , Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg; the Swedish Hip Arthroplasty Register, Gothenburg , Sweden.
Maziar
M
Mohaddes
Ola
O
Rolfson
Johan
J
Kärrholm
D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001168:Arthritis / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D016016:Proportional Hazards Models; D011475:Prosthesis Failure; D012042:Registries; D012086:Reoperation / Q000295:instrumentation / Q000706:statistics & numerical data; D013548:Sweden; D016896:Treatment Outcome; D055815:Young Adult
D008670:Metals