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 .
Arthopor 2 acetabular component with screw fixation in primary hip arthroplasty: a 7- to 9-year follow-up study.
The first 100 consecutive primary hip arthroplasties with the Arthopor 2 acetabular component ( Joint Medical Products , Stamford , CT ) with supplemental screw fixation performed by the senior author were prospect ively studied . The mean patient age was 57 years . Seventy-seven cemented and 23 cementless stems were placed , with 32-mm femoral heads used in most of the patients . Eighty-six hips were review ed at 7 - 8.8 years ( mean , 7.8 years ) . The mean Harris hip score at final follow-up evaluation was 94 points . No cups have been revised , although 2 cups in patients with radiation osteonecrosis were loose radiographically . One patient underwent revision of a severely worn liner . Despite a relatively high mean linear wear rate of 0.27 mm/y ( range , 0.13 - 0.57 mm/y ) , no radiographic evidence of pelvic osteolysis was seen . The Arthopor 2 cup performed well with respect to pelvic osteolysis , despite the presence of substantial polyethylene debris . The relatively high polyethylene wear rate is attributed in part to the younger patient population and the use of 32-mm femoral heads paired with thin polyethylene liners
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 .