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 .
Causes of early failure in a multicenter clinical trial of hip resurfacing.
The purpose of this study was to evaluate the clinical outcomes and possible causes of early failure in a multicenter trial of metal-on-metal hip resurfacing . Two hundred patients were prospect ively enrolled and followed for an average of 31.2 months ( range , 12 - 54 months ) . Of 200 patients , 14 ( 7.0 % ) required revision surgery at a mean time of 19.5 months ( range , 3 - 47 months ) . Patients with failures were significantly younger and heavier than the nonfailures , and all were male . Patients who were revised did not differ from those who were not revised in terms of radiographic outcomes , but they did report lower functional outcome scores at all preoperative and postoperative testing intervals . Most failures ( 10/14 ) were related to early acetabular loosening . The learning curve was likely a factor in these cup failures . This report highlights the importance of patient selection and surgical technique in hip resurfacing arthroplasty . It is anticipated that further surgical experience will lead to a reduction in this high early failure rate
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 .