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 Can Dual Mobility Cups prevent Dislocation in All Situations After Revision Total Hip Arthroplasty? Causes for revision of dual-mobility and standard primary total hip arthroplasty The dual-mobility POLARCUP: first results from a multicenter study. Comparison of dual-mobility cup and unipolar cup for prevention of dislocation after revision total hip arthroplasty Dual-Mobility Cup and Cemented Femoral Component: 6 Year Follow-Up Results Cementless dual-mobility cup in total hip arthroplasty revision A Dual-mobility Cup Reduces Risk of Dislocation in Isolated Acetabular Revisions Results of Charnley total hip arthroplasty at a minimum of thirty years. A concise follow-up of a previous report. Dual mobility cups hip arthroplasty as a treatment for displaced fracture of the femoral neck in the elderly. A prospective, systematic, multicenter study with specific focus on postoperative dislocation. Total hip arthroplasty and hemiarthroplasty in mobile, independent patients with a displaced intracapsular fracture of the femoral neck. A randomized, controlled trial. Are Hip Precautions Necessary Post Total Hip Arthroplasty? A Systematic Review Second-Generation Cementless Total Hip Arthroplasty: Eight to Eleven-Year Results Acetabular reconstruction using a Kerboull cross-plate, structural allograft and cemented dual-mobility cup in revision THA at a minimum 5-year follow-up. Dislocation of Primary Total Hip Arthroplasty with 36 and 40-mm Femoral Heads Clinical outcomes, survivorship and adverse events with mobile-bearings versus fixed-bearings in hip arthroplasty-a prospective comparative cohort study of 143 ADM versus 130 trident cups at 2 to 6-year follow-up.
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 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 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 Background and purpose — Revision total hip arthroplasty ( THA ) is associated with higher dislocation rates than primary THA . We compared the risk of dislocation within 6 months and all-cause re-revision during the whole study period using either the dual-mobility cup or the unipolar cup . Methods — We used a prospect i ve hospital registry-based cohort including all total and cup-only revision THAs performed between 2003 and 2013 . The cups used were either dual-mobility or unipolar ; the choice was made according to the preference of the surgeon . 316 revision THAs were included . The mean age of the cohort was 69 ( 25–98 ) years and 160 THAs ( 51 % ) were performed in women . The dual-mobility group ( group 1 ) included 150 THAs ( 48 % ) and the mean length of follow-up was 31 ( 0–128 ) months . The unipolar group ( group 2 ) included 166 THAs ( 53 % ) and the mean length of follow-up was 52 ( 0–136 ) months . Results — The incidence of dislocation within 6 months was significantly lower with the dual-mobility cup than with the unipolar cup ( 2.7 % vs. 7.8 % ) . The unadjusted risk ratio ( RR ) was 0.34 ( 95 % CI : 0.11–1.02 ) and the adjusted RR was 0.28 ( 95 % CI : 0.09–0.87 ) . The number of patients needed to treat with a  dual-mobility cup in order to prevent 1 case of dislocation was 19 . The unadjusted incidence rate ratio for all-cause re-revision in the dual-mobility group compared to the unipolar group was 0.6 ( 95 % CI : 0.3–1.4 ) . Interpretation — Use of a dual-mobility rather than a unipolar cup in revision THA reduced the risk of dislocation within 6 months Use of a dual-mobility acetabular cup is associated with a lower risk of dislocation compared with conventional hip implants . The seleXys ® DS acetabular cup combines the advantages of Charnley low-friction arthroplasty with those of dual mobility . We performed a non-r and omised , prospect i ve study of patients receiving primary hip arthroplasty , including an uncemented seleXys ® DS dual-mobility acetabular cup with hydroxyapatite coating ( Mathys AG , Bettlach , Switzerl and ) and a cemented femoral component ( Stallion femoral stem Groupe Lepine , Lyon , France ) . The objective of the study was to evaluate longevity of the implant and the risk of dislocation . All operations were performed by a single surgeon using a posterior approach , with patients lying in the lateral decubitus position . The stem had a modular head diameter of 22.2 mm and was cemented in all patients . A total of 53 patients were studied , and the median duration of follow-up was 78.9 months . Implant survival 6 years after surgery was 98.4 % ( n=47 ; 95 % CI : 89.3–99.8 ) . There was one revision for sepsis 29 months after surgery , and one dislocation . The results of this study appear to demonstrate excellent implant survival and a low rate of dislocation using the chosen implants 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 Background Isolated acetabular revisions using st and ard cups are at risk of dislocation . The introduction of a nonconstrained dual-mobility cup was design ed to improve prosthetic stability without increasing loosening rates , but it is unclear whether the risk of dislocation is reduced . Questions / purpose sWe therefore determined : ( 1 ) if the rate of dislocation in isolated acetabular revisions is lower with a dual-mobility cup , ( 2 ) implant survival , ( 3 ) patient function , and ( 4 ) radiographic incidence of migration , loosening , and osteolysis . Methods We prospect ively followed 33 selected patients who underwent isolated acetabular revisions with a minimum of 2 years ’ followup ( mean , 3 years ; range , 2–5 years ) . In 24 patients a stainless steel dual-mobility cup was cemented into an antiprotrusio cage , whereas in nine we used a hyaluronan dual-mobility revision cup with a foramen hook and superior and posterior flanges screw fixations . We determined Harris hip ( HHS ) and WOMAC scores and examined radiographs for migration , loosening , and osteolysis . Results There were no dislocations . Survivorship rates of the femoral and acetabular components were 97 % at 5 years ; the rerevision rate for any reason was 3 % . At last followup , the mean HHS increased from 48 points preoperatively to 86 points . No patients had progressive osteolysis , component migration , or loosening on radiographs . Conclusion In this select group of isolated acetabular revisions , our data suggest the use of a dual-mobility cup reduced the risk of dislocation without increasing loosening from 2 to 5 years . Level of Evidence Level IV , therapeutic study . See the Guidelines for Authors for a complete description of levels of evidence 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 INTRODUCTION Displaced fractures of the femoral neck in the elderly are best treated with arthroplasty . The type of arthroplasty to be used , either hemi- or total hip arthroplasty , remains controversial as total hip replacements potentially have a higher rate of dislocation . HYPOTHESIS Dual mobility cups have a low dislocation rate when used to manage acute fractures of the femoral neck . PATIENTS AND METHODS In a multicenter prospect i ve study conducted in France over an inclusion time of 3 months , all displaced fractures of the femoral neck treated with arthroplasty  were operated on with insertion of a dual mobility cup . Patients had clinical and radiological assessment at 3 , 6 , and 9 months postoperative . RESULTS Two hundred and fourteen hips in 214 patients with a mean age of 83 years ( range , 70 - 103 years ) were included . None of the patients was lost to follow-up . The mortality rate after 9 months was 19 % . Two patients ( 1 % ) had early postoperative infection successfully treated with lavage and antibiotics . Three patients ( 1.4 % ) , operated through a posterior approach , presented one postoperative dislocation , all of which were posterior . Reduction was performed through closed external manipulation under general anesthesia . There was no recurrence of dislocation . DISCUSSION This low rate of dislocation after acute total hip replacement using dual mobility design cups favorably compares with hemiarthroplasties . Dual mobility cups might therefore be considered a valuable option to prevent postoperative dislocation when treating displaced intracapsular fractures of the proximal femur in elderly patients if a total hip replacement is recommended . Further study is needed before extending the indications for total hip arthroplasty following a fracture of the femoral neck , to assess the potential cost and complications of a longer procedure with its potential acetabular complication , and weigh them against the potential benefits BACKGROUND Hemiarthroplasty and total hip arthroplasty are commonly used to treat displaced intracapsular fractures of the femoral neck , but each has disadvantages and the optimal treatment of these fractures remains controversial . METHODS In the present prospect ively r and omized study , eighty-one patients who had been mobile and lived independently before they had sustained a displaced fracture of the femoral neck were r and omized to receive either a total hip arthroplasty or a hemiarthroplasty .  The mean age of the patients was seventy-five years . Outcome was assessed with use of the Oxford hip score , and final radiographs were assessed . RESULTS After a mean duration of follow-up of three years , the mean walking distance was 1.17 mi ( 1.9 km ) for the hemiarthroplasty group and 2.23 mi ( 3.6 km ) for the total hip arthroplasty group , and the mean Oxford hip score was 22.3 for the hemiarthroplasty group and 18.8 for the total hip arthroplasty group . Patients in the total hip arthroplasty group walked farther ( p=0.039 ) and had a lower ( better ) Oxford hip score ( p=0.033 ) than those in the hemiarthroplasty group . Twenty of thirty-two living patients in the hemiarthroplasty group had radiographic evidence of acetabular erosion at the time of the final follow-up . None of the hips in the hemiarthroplasty group dislocated , whereas three hips in the total hip arthroplasty group dislocated . In the hemiarthroplasty group , two hips were revised to total hip arthroplasty and three additional hips had acetabular erosion severe enough to indicate revision . In the total hip arthroplasty group , one hip was revised because of subsidence of the femoral component . CONCLUSIONS Total hip arthroplasty conferred superior short-term clinical results and fewer complications when compared with hemiarthroplasty in this prospect ively r and omized study of mobile , independent patients who had sustained a displaced fracture of the femoral neck Purpose : Total hip arthroplasty ( THA ) is a common and effective treatment of hip osteoarthritis . Activity restrictions known as hip pre caution s are widely practice d in rehabilitation post THA , aim ing to foster healing and prevent hip dislocation . The focused clinical question was : Does the application of hip pre caution s in patients post THA versus unrestricted activities significantly decrease the risk of prosthetic dislocation ? Methods : A comprehensive literature search was conducted for r and omized controlled trials or cohort studies with a comparative group and minimum 6 months follow-up , with dislocation as an end point . Retrieved titles were assessed independently by 2 review ers for inclusion and underwent st and ardized data extraction . Results : Title search produced 80 potentially relevant articles . Five articles were retrieved for data extraction of which 2 met a prior eligibility criteria . No eligible studies were found that concerned posterior approaches to hip arthroplasty , so the results of this review concern only anterolateral approaches . Neither included study showed any benefit of hip pre caution s in preventing dislocation . Conclusion : The rate of dislocation after anterolateral THA is low and is not improved by hip pre caution s. Hip pre caution s are associated with a slower return to activities , significant expense , and decreased patient satisfaction . Existing studies risk being compromised by a type II error , but a definitive study may be prohibitively large and expensive Background : Second-generation cementless femoral components were design ed to provide more reliable ingrowth and to limit distal osteolysis by incorporating circumferential proximal ingrowth surfaces . We examined the eight to eleven-year results of total hip arthroplasty with a cementless , anatomically design ed femoral component and a cementless hemispheric acetabular component . Methods : Ninety-two consecutive primary total hip arthroplasties with implantation of a femoral component with a circumferential proximal porous coating ( Anatomic Hip ) and a cementless hemispheric porous-coated acetabular component ( Harris-Galante II ) were performed in eighty-five patients . These patients were prospect ively followed clinical ly and radiographically . Six patients ( seven hips ) died and five patients ( seven hips ) were lost to follow-up , leaving seventy-four patients ( seventy-eight hips ) who had been followed for a mean of ten years ( range , eight to eleven years ) . The mean age at the time of the arthroplasty was fifty-two years . Results : The mean preoperative Harris hip score of 51 points improved to 94 points at the time of final follow-up ; 86 % of the hips had a good or excellent result . Thigh pain was reported as mild to severe after seven hip arthroplasties . No femoral component was revised for any reason , and none were loose radiographically at the time of the last follow-up . Two hips underwent acetabular revision ( one because of dislocation and one because of loosening ) . Kaplan-Meier survivorship analysis was performed with revision or loosening of any component as the end point . The ten-year survival rate was 96.4 % ± 2.1 % for the total hip prosthesis , 100 % for the femoral component , and 96.4 % ± 2.1 % for the acetabular component . Radiolucencies adjacent to the nonporous portion of the femoral component were seen in sixty-eight ( 93 % ) of the -seventy-three hips with complete radiographic follow-up . Femoral osteolysis proximal to the lesser trochanter was noted in four hips ( 5 % ) . No osteolysis was identified distal to the lesser trochanter . Periacetabular osteolysis was identified in twelve hips ( 16 % ) . Five patients underwent exchange of the acetabular liner because of polyethylene wear . Conclusions : This second-generation cementless , anatomically design ed femoral component provided excellent clinical and radiographic results with a 100 % survival rate at ten years . The circumferential porous coating of this implant improved ingrowth and prevented distal osteolysis at a mean of ten years after the arthroplasty The current study aim ed to evaluate the outcome of a continuous and prospect i ve series of 61 revision THAs with AAOS grade III and IV acetabular bone defect reconstruction using a Kerboull cross-plate , structural allograft and cemented dual mobility cup ( Saturne , Amplitude , Valence , France ) . At a 7.5-year mean follow-up , no instability was reported after revision . In addition , no failure of the acetabular reconstruction was observed in 98 % of the patients with complete allograft osseointegration and no evidence of mechanical rupture of the Kerboull cross-plate and /or loosening of the cemented dual mobility cup . In conclusion , such reconstruction technique demonstrated excellent results at mid-term follow-up in terms of prevention of instability after revision , restoration of the acetabular bone stock , and stable cemented fixation of the dual mobility cup 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 The principle of dual mobility cups , often called " tripolar " , has been developed to overcome the problem of instability following primary hip arthroplasty . We prospect ively compared two cohorts which differed only by the type of bearings , i.e. " mobile bearing hip " ( MBH ) in a 143- study cohort of ADM cups versus " fixed bearing hip " ( FBH ) of 130 Trident PSL cups  , at a follow-up at 2 - 6years . The survival rates at 4.13-years , with instability as endpoint was significantly ( P=0.0176 ) in favor of mobile bearings at 100 % with no dislocation reported , versus 94.8 % with fixed bearings . These mobile bearings , matching both " modern " dual mobility cups and annealed highly crossed polyethylene , would appear to offer at longer follow-up a valuable solution to clinical outcomes in acetabular arthroplasty
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 ) .