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 .
Early results of primary Birmingham hip resurfacings. An independent prospective study of the first 230 hips.
We describe the experience with the first consecutive 230 Birmingham hip resurfacings at our centre . At a mean follow-up of three years ( 25 to 52 months ) survivorship was 99.14 % with revision in one patient for a loose acetabular component and one death from unrelated causes . One patient developed a fracture of the femoral neck at six weeks which united unremarkably after a period of non-weight-bearing . The Harris hip score improved from a mean of 62.54 ( 8 to 92 ) to 97.74 ( 61 to 100 ) . The mean flexion improved from 91.52 degrees ( 25 to 140 ) to 110.41 degrees ( 80 to 145 ) . Most patients ( 97 % ) considered the outcome to be good or excellent . Our preliminary experience with this implant is encouraging and the results are superior to the earlier generation of resurfacings for the same length of follow-up
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 .