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 .
Changes in Proximal Femoral Bone Mineral Density around a Hydroxyapatite-Coated Hip Joint Arthroplasty
Objective . To present the results of a prospect i ve analysis of proximal femoral bone mineral density changes around a hydroxyapatite-coated total hip joint replacement . Methods . 14 patients with osteoarthritis of the hip were enrolled in the study and treated with an uncemented ABG prosthesis . Dual energy X-ray absorptiometry scanning was performed in 9 patients preoperatively , and at 3 , 6 , 12 , and 24 months postoperatively . An orthopaedic software program was used to determine the bone mineral density in the proximal femur , expressed as a percentage of the preoperative value . Results . The values of Gruen zones 1 to 6 averaged between 96.0 % and 113.8 % of the preoperative value by 24 months ( overall average , 104.1 % ) . In zone 7 , however , there was a gradual decline in bone mineral density to an average of 72.1 % of the preoperative value by 24 months . This represented ongoing loss of bone from the calcar ; although this may not pose a problem to the prosthetic 's short-term stability , it may render potential revision surgery more difficult . Conclusion . The initial outcome of uncemented total hip replacement appears to be promising . There was excellent maintenance of bone around the femoral component in all regions other than the calcar and lesser trochanter . Further scans are required to see if these trends continue in the long term
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 .