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Study links age, gender, OA with higher risk for MoM THA revision
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Data from a registry study indicates that cementless metal-on-metal total hip arthroplasty is associated with higher risk of revision at mid-term follow-up compared to the same procedure performed with metal-on-polyethylene bearings.
“At 10-years follow-up, we found a higher relative risk for any revision of cementless stemmed metal-on-metal [MoM] total hip arthroplasty [THA] in general, and for certain groups of patients compared to metal-on-poly THA,” Claus Varnum, MD, of the University of Southern Denmark, said during a presentation at a recent meeting.
Using data from the Nordic Arthroplasty Register Association, investigators reviewed data for 85,371 primary cementless THAs performed from 2002 to 2010. Data for patients who underwent bilateral THA only included information for the first hip. Exclusion criteria included diagnosis of hip fracture, another additional diagnosis, and patients with other bearing types or patients with incomplete information on their diagnosis, bearing type or femoral size used. The investigators included data on 33,067 patients for their study, of which 11,574 patients (35%) received MoM constructs and 21,493 (65%) received metal-on-polyethylene combinations.
Varnum and his colleagues found a larger number of younger and male patients in the MoM cohort compared with the metal-on-polyethylene group. Patients in the MoM group also had a slightly longer follow-up. In addition, at both 6-year and 10-year follow-up, the overall relative risk for revision was higher among MoM recipients.
“When performing a stratified analysis, we found that the adjusted risk ratio at 10-years follow-up was higher for men younger than 60 years, for women aged 60 years or older, for patients with osteoarthritis as a diagnosis, and for revisions due to aseptic loosening, but the adjusted risk ratio at 10 years was lower for MoM bearings for revision due to dislocation,” Varnum said.
In addition, cup and stem component combinations correlated with outcomes. Stratified analysis on these groups compared particular component bearing pairings against all possible metal-on-polyethylene components. According to Varnum, “the combination of ASR/Summit [DePuy], ASR/Corail [DePuy] and ‘other’ combinations had higher adjusted relative risks at 6-years follow-up.”– by Katie Pfaff
Reference:
Varnum C. Risk for revision of metal-on-metal cementless stemmed total hip arthroplasty: Data from the Nordic Arthroplasty Registry Association. Presented at: EFORT Congress; June 4-6, 2014; London.
For more information:
Claus Varnum, MD, can be reached at University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark; email: claus.varnum@rsyd.dk.
Disclosure: Varnum has no relevant financial disclosures.