Conclusions Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing , except when discontinued devices are removed from the analyses .
Background Metal-on-metal hip resurfacing was developed for younger , active patients as an alternative to THA , but it remains controversial .
Study heterogeneity , inconsistent outcome definitions , and unst and ardized outcome measures challenge our ability to compare arthroplasty outcomes studies .
Questions / purpose sWe asked how early revisions or reoperations ( within 5 years of surgery ) and overall revisions , adverse events , and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA  among patients with hip osteoarthritis .
Secondarily , we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries .
Matched-pair analysis of cemented and cementless acetabular reconstruction in primary total hip arthroplasty.
In a matched-pair study of primary total hip arthroplasty , 45 all-polyethylene cemented acetabular components were compared with 45 cementless , hemispheric , titanium acetabular components .  At 9 to 12 years , 1 of the cemented acetabular components was revised for aseptic loosening , and 14 ( 31 % ) were radiographically loose . Nine ( 20 % ) cemented acetabular components had pelvic osteolysis . In the cementless acetabular component group , 2 well-fixed components were revised . No components were radiographically loose , and 3 ( 7 % ) had pelvic osteolysis . Thirty-eight ( 97 % ) of the patients in each group were satisfied with the surgery . The clinical results of the cemented and cementless components were excellent . The cementless components had less loosening ( P < .001 ) than the cemented components
Conclusions Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing , except when discontinued devices are removed from the analyses .
Background Metal-on-metal hip resurfacing was developed for younger , active patients as an alternative to THA , but it remains controversial .
Study heterogeneity , inconsistent outcome definitions , and unst and ardized outcome measures challenge our ability to compare arthroplasty outcomes studies .
Questions / purpose sWe asked how early revisions or reoperations ( within 5 years of surgery ) and overall revisions , adverse events , and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA  among patients with hip osteoarthritis .
Secondarily , we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries .