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 .
Is the Charnley evolution working? A five-year outcome study.
Two hundred consecutive primary total hip arthroplasties ( 196 patients ) carried out between January 1994 and May 1995 using the Elite Plus cemented femoral components ( DePuy International , Leeds , UK ) were enrolled in a prospect i ve study . Fifteen patients were lost to follow-up . The patients were evaluated clinical ly using the Harris Hip Score ( HHS ) and radiographically . The mean HHS was raised from 39.3 preoperatively to 89.6 at 5 years . Radiologically the mean femoral subsidence was 1.40 mm at 5 years . The mean annual rate of re-operation was 0.2 % . There were no revisions for aseptic loosening . In the present series , the Elite Plus hip arthroplasty has produced clinical and radiological results , which are comparable with the Charnley hip at five years
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 .