Conclusion Based on the current data , the use of DM acetabular components are effective in minimising the risk of instability after both primary and revision THA .
This benefit must be balanced against continuing concerns about the additional modularity , and the new mode of failure of intraprosthetic dislocation .
Aims The aim of this systematic review was to report the rate of dislocation following the use of dual mobility ( DM ) acetabular components in primary and revision total hip arthroplasty ( THA ) .
Relationship of Femoral Head and Acetabular Size to the Prevalence of Dislocation
Two clinical studies , one prospect i ve r and omized and one retrospective , were performed to evaluate the relationship of femoral head size and acetabular component outer diameter to the prevalence of dislocation of the  modular total hip replacement . Between October 1995 and April 1996 , 31 primary total hip arthroplasties in 30 patients were r and omized to a femoral head diameter of 22 mm or 28 mm , for two groups of acetabular components of outer diameters of 56 mm or larger and 54 mm or smaller . Head size ( 22 mm ) and acetabular component outer diameter ( ≥ 56 mm ) were found to increase the risk of dislocation . From December 1984 to January 1994 , 308 primary total hip arthroplasties were performed through a posterior approach by one surgeon using a modular 28 mm femoral head and one type of uncemented acetabular component .  The rate of dislocation for acetabular components with an outer diameter of 62 mm or larger was increased significantly ( five of 36 hips , 14 % ) compared with those with an outer diameter of 60 mm or smaller ( 11 of 272 hips , 4 % )
Conclusion Based on the current data , the use of DM acetabular components are effective in minimising the risk of instability after both primary and revision THA .
This benefit must be balanced against continuing concerns about the additional modularity , and the new mode of failure of intraprosthetic dislocation .
Aims The aim of this systematic review was to report the rate of dislocation following the use of dual mobility ( DM ) acetabular components in primary and revision total hip arthroplasty ( THA ) .