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 .
Resurfacing is Comparable to Total Hip Arthroplasty at Short-term Followup
Abstract Metal-on-metal total hip resurfacing arthroplasty has had excellent reported results at early to midterm followup , and some studies suggest that outcomes are comparable to conventional THA . We compared the clinical and radiographic outcomes of two closely matched groups of 54 patients who underwent resurfacing and conventional THA , respectively . Each group consisted of 36 men and 18 women who had a mean age of 52 years and a mean body mass index of 29 kg/m2 . At a minimum followup of 24 months ( mean , 40 months ; range , 24–60 months ) , the mean Harris hip scores increased similarly in both groups ( from 52 to 90 points and from 50 to 91 points for the resurfacing and conventional groups , respectively ) . Radiographic outcomes , revision rates , complications , pain scores , and satisfaction ratings of the two groups were similar . The patients who underwent resurfacing had higher postoperative weighted activity scores than the patients who underwent conventional THA , although they had higher preoperative weighted activity scores as well . The early outcomes of resurfacing are comparable to those of conventional THA . Level of Evidence : Level III , therapeutic study . See the Guidelines for Authors for a complete description of levels of evidence
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 .