Nationwide review of mixed and non-mixed components from different manufacturers in total hip arthroplasty

I read with great interest the recent paper by Peters et al. (2016) “Nationwide review of mixed and non-mixed compo- nents from different manufacturers in total hip arthroplasty: a Dutch Arthroplasty Register study.” In this study the authors used the data of a nationwide database to compare the revision rate of primary total hip arthroplasty (THA) with components of the same or different manufacturers. Overall, they found similar medium-term revision rates for both groups. Currently, surgeons implanting not approved mixed combi- nations do so under their own liability (Michel 2009). How- ever, some mixed combinations used in high numbers have a similar revision rate compared with matched combinations. In cemented THA, the overall implant survivorship is even better in the mixed group than in the matched group (Tucker et al. 2015). The hip implant in the National Joint Registry for England, Wales and Northern Ireland that has the best perfor- mance is the Exeter stem (Stryker) in combination the Elite Plus Cemented Cup (DePuy Synthes) (National Joint Registry - Annual Report 2014).