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 .
Birmingham Hip Resurfacing in Patients who are Seventy Years of Age or Older
There is no published literature to support mid to long term results of hip resurfacing ( HR ) arthroplasty in patients over the age of 70 years . The purpose of our study was to evaluate the function HR in this age group ( 70 or older at the time of surgery ) at medium to long term follow-up . Between July 1997 and November 2002 , the Oswestry Outcome Centre independently and prospect ively collected data on 5000 Birmingham Hip Resurfacings ( BHRs ) . 106 had been implanted in elderly patients who were 70 years of age or older . The post-operative Harris and Merle D'Aubigné and Postel ( MDP ) hip scores and causes for revision were used to ascertain function and implant survival . Hip scores for the older BHR patients were compared with those from younger patients . The average age at surgery of the elderly BHR cohort was 73.2 years ( range , 70.0 to 87.9 years ) with a mean follow-up of 7.1 years ( range , 0.5 to 10.9 years ) . Four patients had a femoral neck fracture and required conversion to a conventional total hip replacement . There were no patients lost to follow-up and no dislocations in this series . The median Harris hip score ( HHS ) was significantly better in the younger BHR group compared with the elderly BHR group , ( 96 vs. 94 p=0.008 ) . There was no significant difference in recovery rates after surgery . There was a significantly higher rate of revision in women than men among the elderly patients ( male= 1 of 65 ( 1.5 % ) ; women = 3 of 19 ( 15.8 % ) , p=0.03 ) . At latest follow-up the elderly patients continued to function well when compared with the younger BHR patients . There was a high mid to long term success rate after HR in patients who were 70 years of age or older , without the failure burden possibly anticipated . Elderly patients had a poorer functional outcome , but a difference in HHS of two points may be of only minor clinical significance
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 .