Causes for revision of dual-mobility and standard primary total hip arthroplasty The dual-mobility POLARCUP: first results from a multicenter study. Results of Charnley total hip arthroplasty at a minimum of thirty years. A concise follow-up of a previous report. Can Dual Mobility Cups prevent Dislocation in All Situations After Revision Total Hip Arthroplasty? Cementless dual-mobility cup in total hip arthroplasty revision Early experience with dual mobility acetabular systems featuring highly cross-linked polyethylene liners for primary hip arthroplasty in patients under fifty five years of age: an international multi-centre preliminary study Dislocation of Primary Total Hip Arthroplasty with 36 and 40-mm Femoral Heads
Introduction The causes for revision of primary total hip arthroplasty ( THA ) are various and quite well known . The developing use of dual-mobility THA ( DM-THA ) seems a relevant option to decrease the risk of instability . Due to lack of long-term follow-up , this innovative retentive concept is suspected to increase the risk of polyethylene ( PE ) wear . the aim of the study was to analyse the causes for  DM-THA revision and assess whether or not its occurrence is different from that of fixed-st and ard ( FS ) THA , particularly for aseptic loosening or wear and /or osteolysis . Material s and methods The SoFCOT group conducted an observational prospect i ve multicentre study from 1 January 2010 to 31 December 2011 . Inclusion criteria comprised an exhaustive collection of 2044 first-revision THAs with 251 DM-THAs and 1793 FS-THAs . After excluding complications linked to patient factors ( infection and periprosthetic fractures ) , we performed a matched case – control study ( matching ratio 1:1 ) comparing two groups of 133 THAs . Results Revisions for aseptic loosening or osteolysis/wear were as frequent in DM-THA ( 58.7 % ) as in FS-THA ( 57.1 % ) ( p 0.32 ) ; 7.5 % of DM-THA were revised for dislocation versus 19.5 % of FS-THA ( p 0.007 ) . Discussion Revision for osteolysis/wear and aseptic loosening were as frequent in DM-THA as in FS-THA ;  revision for dislocation was less frequent in DM-THA . This confirms the efficiency of the DM concept regarding the risk of dislocation . Causes for revision were different between groups , and revisions for dislocation were less frequent in DM-THA . Only prospect i ve comparative studies could provide reliable information that may support broader use of the DM concept Dislocation is a leading cause of revision after  total hip arthroplasty ( THA ) . To address this risk , dual-mobility technology was developed , which features a mobile polyethylene liner locked onto a femoral head and articulating in a metallic acetabular shell . This study reports clinical outcome data after implantation of the third-generation POLARCUP Dual-Mobility System ( Smith & Nephew Orthopaedics AG , Rotkreuz , Switzerl and ) .  Primary THA procedures were performed in 150 patients . At 7.1 years , cumulative cup survival according to Kaplan-Meier was 97.4 % . The mean Postel-Merle d'Aubigne score improved from 8.9 to 17.1 during the investigation . Two cups were revised at 5.4 and 6.4 years because of aseptic loosening . No dislocations were observed during follow-up . The current results confirm excellent early to midterm clinical outcomes for the POLARCUP Dual-Mobility System The purpose of the current study was to up date the results of a prospect i ve , single-surgeon series of primary Charnley total hip arthroplasties performed with cement . This investigation is one of the first studies in which hips treated with total hip arthroplasty with cement  were followed for a minimum of thirty years . Twenty-seven patients ( thirty-four [ 10.3 % ] of the hips in the initial study group ) were alive at a minimum of thirty years postoperatively . These patients served as the focus of the present study .  Revision because of aseptic loosening of the acetabular component was performed in 7.3 % ( twenty-three ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 26 % ( eight ) of the hips in the living cohort .  Revision  because of aseptic loosening of the femoral component was performed in 3.2 % ( ten ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 10 % ( three ) of the hips in the living patients . Since the twenty-five-year review , three hips were revised ( one because of acetabular loosening , one because of femoral loosening , and one because of instability ) . This end- result study demonstrated the remarkable durability of cemented Charnley total hip replacements over a span of three decades , with 88 % of the original prostheses intact at the time of the final follow-up or at the patient 's death UNLABELLED The outcome of a single design of dual mobility cup was prospect ively evaluated in a continuous series of 994 revision THAs with respect to dislocation and intra-prosthetic dislocation ( IPD ) . At a 7.3-year mean follow-up , the dislocation rate was 1.5 % and the IPD rate was 0.2 % . The 2 IPD occurred in acetabular-only revisions and were related to a poor head-to-neck ratio with early impingement and wear at the polyethylene mobile component chamfer . Dual mobility cups demonstrated a low dislocation rate in revision THA but did not compensate for potential perioperative technical errors . In addition , IPD did not appear to be a concern with respect to the benefit in term of instability prevention though caution is advised in acetabular-only revision associated with a poor head-to-neck ratio . LEVEL OF EVIDENCE Therapeutic study -Level IV Purpose Dislocation is a frequent complication in total hip arthroplasty ( THA ) revision . Cup fixation is the second concern . In order to know outcomes at two years , we prospect ively followed a continuous series of 78 patients to demonstrate that  cementless dual-mobility cup ( DMC ) used in revision THA  is safe as regards dislocation risk and bone fixation . Method We enrolled 78 consecutive patients ( 79 cases ) in a prospect i ve study . Mean interval between index surgery and revision was 12.9 years . Mean age at revision was 75.5 years . Two types of cementless DMC were used : a st and ard DMC in 68 cases with low- grade bone defect ( Paprosky grade 1 and 2 ) , and a specific design reconstruction DMC in 11 cases with severe bone loss ( Paprosky grade 3 ) . Results At two years of follow-up , 68 patients were review ed ; four were lost to follow-up . , and six patients were deceased . We identified three types of situations at risk : st and ard risk ( 33 cases ) , Paprosky grade 1 or 2 ; medium risk ( 37 cases ) , revision for recurrent instability ( 21 ) , periprosthetic fractures ( 14 ) or severe loosening Paprosky grade 3 without femorotomy ( 2 ) ; high risk ( nine cases ) , revision for severe loosening with a femorotomy . One ( 1.3 % ) patient dislocated her hip at one month without recurrence . Revision rate for dislocation was 0 % ; two ( 2.7 % ) early mechanical failures occurred . Conclusion Considering outcomes of this series , cementless DMC can be suggested in THA revision surgery Purpose To evaluate early performance of contemporary dual mobility acetabular systems with second generation annealed highly cross-linked polyethylene for primary hip arthroplasty of patients under 55 years of age . Methods A prospect i ve observational five years study across five centers in Europe and the USA of 321 patients with a mean age of 48.1 years was performed . Patients were assessed for  causes of revision , hip instability , intra-prosthetic dissociation , Harris hip score and radiological signs of osteolysis .  Results There were no dislocations and no intra-prosthetic dissociations . Kaplan Meier analysis demonstrated 97.51 % survivorship for all cause revision and 99.68 % survivorship for acetabular component revision at five years . Mean Harris hip score was 93.6 . Two acetabular shells were revised for neck-rim implant impingement without dislocation and ten femoral stems were revised for causes unrelated to dual mobility implants . Conclusion Contemporary highly cross-linked polyethylene dual mobility systems demonstrate excellent early clinical , radiological , and survivorship results in a cohort of patients that dem and high performance from their implants . It is envisaged that DM and second generation annealed HXLPE may reduce THA instability and wear , the two most common causes of THA revision in hip arthroplasty Some authors suggest the use of larger ( 36 and 40 mm ) femoral heads against highly cross-linked polyethylene acetabular liners will reduce the prevalence of early dislocation after primary total hip arthroplasty ( THA ) . We prospect ively followed 61 consecutive patients at high risk for dislocation to determine the prevalence of early dislocation after primary THA with 36 and 40 mm femoral heads .  We established specific indications for the use of these larger heads in primary arthroplasty . There were 65 hips in 61 patients with a minimum followup of 1 year ( mean 2 years , range 1 - 4 years ) . There were 55 36 mm heads and 10 40 mm heads . All arthroplasties were performed by the posterior approach with capsular repair . The prevalence of early dislocation was 4.6 % ( 3 of 65 ) . There was one patient with an anterior dislocation and two with posterior dislocation . No patient underwent reoperation for dislocation . There was no dislocation in the 10 hips that had a 40 mm head . We identified no complications related to the larger femoral heads . The use of larger femoral heads did not notably reduce the prevalence of early dislocation after primary THA in high risk patients compared to historical controls . Therapeutic study : Level IV , case series . See Guidelines for Authors for a complete description of levels of evidence
In short-term outcomes ( 5 years or less , with follow-up of 0–5 years ) , the best implant of choice that has lowest risk of revision and dislocation after THA is DMTHA follow by BTHA .
Abstract Postoperative dislocation is a challenging complication after  total hip arthroplasty ( THA ) that affects patient outcome worldwide .
Instability is one of the main complications with rates exceeding 20 % in some series .
Currently , alternative acetabular components are available with dual mobility ( DMTHA ) bearing surfaces and larger femoral head size that may reduce the risk of dislocation , yet provide the functional benefit of st and ard single mobility ( STHA ) bearing surface THA .
However , whether STHA , big femoral head ( BTHA ) and DMTHA should be used is still controversial .
This systematic review and meta- analysis aim to compare postoperative dislocation and revision ( aseptic loosening and infection ) of BTHA , STHA and DMTHA in primary or revision THA .
These clinical outcomes consist of postoperative dislocation and revision ( aseptic loosening and infection ) .