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 The Frank Stinchfield Award: Dislocation in Revision THA: Do Large Heads (36 and 40 mm) Result in Reduced Dislocation Rates in a Randomized Clinical Trial? A Dual-mobility Cup Reduces Risk of Dislocation in Isolated Acetabular Revisions Comparison of dual-mobility cup and unipolar cup for prevention of dislocation after revision total hip arthroplasty 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. Midterm Survivorship of the Lefèvre Constrained Liner: A Consecutive Multisurgeon Series of 166 Cases. Clinical and radiographic outcomes of total hip arthroplasty with insertion of an anatomically designed femoral component without cement for the treatment of primary osteoarthritis. A study with a minimum of six years of follow-up. Results of Charnley total hip arthroplasty with use of improved femoral cementing techniques. a concise follow-up, at a minimum of twenty-five years, of a previous report. Early complications of anterior supine intermuscular total hip arthroplasty. Dual-Mobility Cup and Cemented Femoral Component: 6 Year Follow-Up Results Influence of preoperative patient education on the risk of dislocation after primary total hip arthroplasty. Large femoral heads decrease the incidence of dislocation after total hip arthroplasty: a randomized controlled trial. Staged bilateral mobile-bearing and fixed-bearing total knee arthroplasty in the same patients: a prospective comparison of a posterior-stabilized prosthesis Conventional versus computer-navigated TKA: a prospective randomized study Custom stems for femoral deformity in patients less than 40 years of age Comparison of Fixed-Bearing and Mobile-Bearing Total Knee Arthroplasties A randomized trial of ceramic-on-ceramic bearing versus ceramic-on-crossfire-polyethylene bearing in total hip arthroplasty: five-year outcomes.
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 Background Dislocation after revision THA is a common complication . Large heads have the potential to decrease dislocation rate , but it is unclear whether they do so in revision THA . Questions / purpose sWe therefore determined whether a large femoral head ( 36 and 40 mm ) result ed in a decreased dislocation rate compared to a st and ard head ( 32 mm ) . Methods We r and omized 184 patients undergoing revision THA to receive either a 32-mm head ( 92 patients ) or 36- and 40-mm head ( 92 patients ) and stratified patients by surgeon . The two groups had similar baseline demographics . The primary end point was dislocation . Quality -of-life ( QOL ) measures were WOMAC and SF-36 . The mean followup for dislocation was 5 years ( range , 2–7 years ) ; the mean followup for QOL was 2.2 years ( range , 1.6–4 years ) . Results In the 36- and 40-mm head group , the dislocation rate was 1.1 % ( one of 92 ) versus 8.7 % ( eight of 92 ) for the 32-mm head . There was no difference in QOL outcomes between the two groups . Conclusions Our observations confirm a large femoral head ( 36 or 40 mm ) reduces dislocation rates in patients undergoing revision THA at short-term followup . We now routinely use large heads with a highly crosslinked polyethylene acetabular liner in all revision THAs . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence 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 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 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 Constrained liners are used as part of a salvage procedure to provide stability for patients at high risk for dislocation after a total hip arthroplasty . However , no recent studies exist highlighting their effectiveness and /or limitations . METHOD This prospect i ve review included 166 consecutive hip arthroplasties , either primary ( 27 % ) or revision ( 73 % ) , with a unique design of a constrained liner : Lefèvre retentive cup . There were 113 females ( 69 % ) , and the average age at index surgery was 75.9 years ( range , 35 - 94 ) . The mean follow-up was 6.2 years ( range , 0.3 - 11 ) . RESULTS Twenty patients had a reoperation ; 10 for infection ( 4 acute and 6 chronic joint infection ) and 10 for cup failure ( 5 fixation failure , 3 aseptic loosening , and 2 dislocation ) . Ten-year survivals for cup revision were 89 % ( CI , 83 - 94 ) and 92 % ( CI , 89 - 97 ) for all revision and revision for noninfectious reasons , respectively . When solely evaluating for dislocation , the survival at 10 years was 99 % ( CI , 97 - 100 ) . Considering primary and revision cases , 10-year survivals cup revision for aseptic reasons were 92.4 % ( CI , 84 - 100 ) and 92.5 % ( CI , 87 - 98 ) , respectively . CONCLUSIONS The Lefèvre retentive cup demonstrated excellent 10-year 's survivorship . With the rate of aseptic loosening around 2 % and a dislocation rate around 1 % , the cup is as effective as other available devices and is therefore a cost-effective tool to reduce the risk of dislocation in at-risk patients undergoing hip arthroplasty We evaluated the clinical and radiographic outcomes of 100 consecutive primary total hip arthroplasties in which a proximally coated anatomically design ed femoral component was fixed without cement for the treatment of primary osteoarthritis . The minimum duration of follow-up was six years ( average , 7.1 years ) . The eighty-eight patients who had the arthroplasties were followed prospect ively with a st and ard clinical evaluation that involved use of the Harris hip score and a radiographic evaluation based on the criteria of the Hip Society . Bone ingrowth was evaluated with the method of Engh et al. The average age of the patients at the time of the operation was 62.6 years ( range , thirty-nine to eighty-four years ) . Fifty-one patients were men and thirty-seven were women . The average preoperative Harris hip score was 48 points , with an average pain score of 15 points and an average function score of 26 points . Nonmechanical complications that necessitated a revision operation included one deep hematogenous infection , one late periprosthetic fracture , and a 0.5-inch ( 1.27-centimeter ) limb-length discrepancy . At the time of the most recent follow-up , the average Harris hip score was 96 points , with an average pain score of 42 points and an average function score of 45 points . The prevalence of pain in the anterior part of the thigh was 5 percent ( five hips ) . One patient had a revision of the femoral component because of aseptic loosening , and one had a revision of the acetabular component because of recurrent dislocations . Radiographic assessment revealed consistent evidence of proximal bone ingrowth . No complete radiolucent line was identified , except around the stem that had loosened . Twenty-seven femoral components were associated with slight pedestal formation . No osteolytic lesion of the femur was identified . Nonprogressive pelvic osteolysis was identified in four hips , but none of the lesions were more than two millimeters in diameter . None of the acetabular components migrated , and no radiolucent line of more than two millimeters in thickness was seen around any acetabular cup . The data from this study , in which the minimum duration of follow-up was six years , indicate that the anatomically design ed prosthesis can provide good results , with low prevalences of pain in the thigh and loosening of the component , in younger , active patients UNLABELLED The current study was performed to determine the status , at a minimum of twenty-five years , of a prospect i ve , single-surgeon series of patients treated with primary Charnley total hip arthroplasty with a contemporary femoral cementing technique that included use of a distal cement plug and a retro grade cement-delivery system . Since our review at a minimum of twenty years postoperatively , two primary total hip prostheses were revised ( one because of acetabular loosening , and one because of femoral loosening ) . Of the original cohort of 357 hips ( 320 patients ) , ten ( 2.8 % ) had revision of the femoral stem because of aseptic loosening . Forty-nine patients ( fifty-two hips , 14.6 % ) who had been in the initial study group were still living at the time of the present review . Five hips ( 10 % ) in living patients had required a femoral revision because of aseptic loosening . Including those that were revised , eight femoral components ( 17 % ) in living patients were seen to be loose radiographically . Although this study demonstrates the remarkable durability of the femoral fixation obtained with the polished flatback Charnley prosthesis and the contemporary cementing technique , there was some deterioration of the results with time . These results provide a st and ard for comparison with cementless fixation after hips treated with that technique have been followed for a similar duration . LEVEL OF EVIDENCE Therapeutic Level IV . See Instructions to Authors for a complete description of levels of evidence Anterior supine intermuscular total hip arthroplasty ( THA ) performed on a fracture table has been increasingly used for primary THA . Accurate cup placement , low incidence of dislocation , shorter hospital stay , and faster return of function are potential benefits of the technique . However , a high complication rate , particularly during a surgeon 's learning curve , has been reported . A retrospective analysis of 61 consecutive anterior supine intermuscular primary THAs with at least 6-month follow-up was performed . All procedures were performed using the anterior supine intermuscular approach with cementless implants under fluoroscopic guidance on a fracture table . Prospect ively collected data were retrospectively review ed to evaluate the early complication rate and radiographic accuracy of implant placement . Five ( 8.2 % ) intraoperative complications were observed : including 3 trochanteric fractures and 2 calcar fractures , 4 of which required cable fixation during the index procedure . One nondisplaced trochanteric fracture was treated conservatively . One patient sustained an injury of the lateral femoral cutaneous nerve . Postoperative complications included 1 anterior dislocation , 1 infected superficial hematoma , 1 stem subsidence , and 1 loose stem , with the latter 2 presenting as increasing thigh pain postoperatively and requiring stem revision . The overall complication rate was 16.4 % ( 10/61 ) . Overall , 3 patients ( 4 hips ; 6.5 % ) required reoperation . No femoral or sciatic nerve injuries occurred , and no patient was diagnosed with venous thromboembolism . All intraoperative fractures occurred during the first 32 cases , and none during the last 29 cases . A potentially high incidence of complications with the anterior supine intermuscular THA exists during a surgeon 's learning curve in an academic setting 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 OBJECTIVE Dislocation is a well-known complication after  total hip arthroplasty ( THA ) , and is the second-highest cause of revision surgery . Our objective was to assess the effect of preoperative patient education on the occurrence of  hip dislocation  within 6 months after primary THA . METHODS Between 1998 and 2007 , we conducted a prospect i ve cohort study at the Geneva University Hospital Department of Orthopaedic Surgery , including all primary THAs performed via an anterolateral transgluteal approach with the use of a 28-mm diameter head .  The preoperative education session was introduced in June 2002 and included advice on muscle strengthening exercises and postoperative restrictions of range of motion as a means of preventing dislocation . The main outcome was the incidence of dislocation within 6 months of surgery . RESULTS A total of 597 patients who underwent 656 THAs between June 2002 and June 2007 participated in the education session , whereas 1,641 patients who underwent 1,945 procedures did not . Forty-six dislocations occurred over the study period , 5 ( 0.8 % ) in participants and 41 ( 2.1 % ) in non participants ( absolute risk reduction 1.3 % ; 95 % confidence interval [ 95 % CI ] 0.4 , 2.3 ) , with the time interval between surgery and dislocation being significantly shorter among participants ( 0.2 versus 1.2 months ) . Non participants had a 2.8 times higher risk of dislocation than participants ( unadjusted odds ratio [ OR ] 2.80 ; 95 % CI 1.10 , 7.13 ) . Adjustment for age , sex , comorbidities , and prior surgery did not change the results ( adjusted OR 2.79 ; 95 % CI 1.09 , 7.15 ) . CONCLUSION Our findings suggest that participation in a preoperative patient education session may reduce the risk of dislocation within 6 months after THA BACKGROUND The use of larger femoral heads has been proposed to reduce the risk of dislocation after total hip arthroplasty , but there is a lack of evidence to support this proposal . The aim of this multicenter r and omized controlled trial was to determine whether the incidence of dislocation one year after total hip arthroplasty is significantly lower in association with the use of a 36-mm femoral head articulation as compared with a 28-mm articulation . METHODS Six hundred and forty-four middle-aged and elderly patients undergoing primary or revision arthroplasty were r and omized intraoperatively to receive either a 36 or 28-mm metal femoral head on highly cross-linked polyethylene .  Patients who were at high risk of dislocation ( including those with dementia and neuromuscular disease ) and those undergoing revision for the treatment of recurrent hip dislocation or infection were excluded . Patients were stratified according to other potential risk factors for dislocation , including diagnosis and age . Diagnosis of hip dislocation required confirmation by a physician and radiographic evidence of a dislocation . RESULTS Overall , at one year of follow-up , hips with a 36-mm femoral head articulation had a significantly lower incidence of dislocation than did those with a 28-mm articulation ( 1.3 % [ four of 299 ] compared with 5.4 % [ seventeen of 316 ] ; difference , 4.1 % [ 95 % confidence interval , 1.2 % to 7.2 % ] ) when controlling for the type of procedure ( primary or revision ) ( p = 0.012 ) . The incidence of dislocation following primary arthroplasty was also significantly lower for hips with a 36-mm femoral head articulation than for those with a 28-mm articulation ( 0.8 % [ two of 258 ] compared with 4.4 % [ twelve of 275 ] ; difference , 3.6 % [ 95 % confidence interval , 0.9 % to 6.8 % ] ) ( p = 0.024 ) . The incidence of dislocation following revision arthroplasty was 4.9 % ( two of forty-one ) for hips with a 36-mm articulation and 12.2 % ( five of forty-one ) for hips with a 28-mm articulation ; this difference was not significant with the relatively small sample size of the revision group ( difference , 7.3 % [ 95 % confidence interval , -5.9 % to 21.1 % ] ) ( p = 0.273 ) . CONCLUSIONS Compared with a 28-mm femoral head articulation , a larger 36-mm articulation result ed in a significantly decreased incidence of dislocation in the first year following primary total hip arthroplasty . However , before a 36-mm metal-on-highly cross-linked polyethylene articulation is widely recommended , the incidence of late dislocation , wear , periprosthetic osteolysis , and liner fracture should be established Mobile-bearing total knee arthroplasty ( TKA ) has several theoretical advantages over fixed-bearing TKA . We conducted a prospect i ve r and omized trial to compare the results of mobile-bearing and fixed-bearing posterior-stabilized TKA in the same patients using the same femoral component design of a mobile-bearing prosthesis in one knee and a fixed-bearing prosthesis in the other knee in 25 patients with osteoarthritis . The mean follow-up was 40 months . No significant differences were found in the mobile-bearing and fixed-bearing knees in terms of clinical and radiographic results . No osteolysis , loosening , or revision occurred . One knee with a mobile-bearing prosthesis had a dislocation of the rotating bearing ; however , spontaneous reduction occurred and the dislocation did not recur . Satisfactory early results can be achieved in both mobile-bearing and fixed-bearing knees . We could not demonstrate an advantage of a mobile-bearing TKA Purpose The purpose of this study was to assess the midterm results of total knee arthroplasty ( TKA ) implanted with  a specific computer navigation system in a group of patients ( NAV ) and to assess the same prosthesis implanted with the conventional technique in another group ( CON ) ; we hypothesized that computer navigation surgery would improve implant alignment , functional scores and survival of the implant compared to the conventional technique . Methods From 2008 to 2009 , 225 patients were enrolled in the study and r and omly assigned in CON and NAV groups ; 240 consecutive mobile-bearing ultra-congruent score ( Amplitude , Valence , France ) TKAs were performed by a single surgeon , 117 using the conventional method and 123 using the computer-navigated approach .  Clinical outcome assessment was based on the Knee Society Score ( KSS ) , the Hospital for Special Surgery Knee Score and the Western Ontario Mac Master University Index score . Component survival was calculated by Kaplan – Meier analysis . Results Median follow-up was 6.4 years ( range 6–7 years ) . Two patients were lost to follow-up . No differences were seen between the two groups in age , sex , BMI and side of implantation . Three patients of CON group referred feelings of instability during walking , but clinical tests were all negative . NAV group showed statistical significant better KSS Score and wider ROM and fewer outliers from neutral mechanical axis , lateral distal femoral angle , medial proximal tibial angle and tibial slope in post-operative radiographic assessment . There was one case of early post-operative superficial infection ( caused by Staph . Aureus ) successfully treated with antibiotics . No mechanical loosening , mobile-bearing dislocation or patellofemoral complication was seen . At 7 years of follow-up , component survival in relation to the risk of aseptic loosening or other complications was 100 % . There were no implant revisions . Conclusion This study demonstrates superior accuracy in implant positioning and statistical significant better functional outcomes of computer-navigated TKA . Computer navigation for TKAs should be used routinely in primary implants . Level of evidence II Background and purpose Femoral deformity associated with osteoarthritis is a challenge for both the surgeon and the implant . Many of the patients with these deformities are young . St and ard implants can be difficult to fit into these femurs . We prospect ively evaluated the outcome of custom uncemented femoral stems in young patients . Methods 61 consecutive patients ( 72 hips ) underwent surgery for osteoarthritis because of femoral deformity at a mean age of 35 ( 22–40 ) years . The patients received a CT3D-A custom-made femoral stem and an uncemented cup . The mean follow-up time was 14 ( 10–16 ) years . 2 patients died at 7 and 8 years after surgery , otherwise , none of the patients were lost to follow-up . Results At follow-up , the femoral prosthesis had not been revised in 59 patients ( 70 hips ) . 3 patients ( 3 hips ) had required revision surgery due to loosening of the acetabular component ; 2 hips were awaiting revision surgery for loosening of the acetabular cup . There were no cases of dislocation or infection . At review , all stems were considered stable according to the radiographic criteria . No migration or subsidence was observed on plain radiographs . Interpretation Our results are comparable to published results of custom stems regarding survival and outcome . Considering the young age and the deformities in this series of uncemented custom femoral stems , and the fact that there was follow-up of up to 16 years , the survival is remarkable . This technique appears to be a reasonable alternative in younger patients with femoral deformities The purpose of the current study was to directly compare the results of fixed-bearing and mobile-bearing total knee arthroplasties in the same patient who had bilateral simultaneous total knee replacements . A fixed-bearing total knee prosthesis ( AMK ) was implanted in one knee and a mobile-bearing total knee prosthesis ( LCS ) was implanted in the other knee in 116 patients . The average age of the patients was 65 years ( range , 33–70 years ) . The average followup was 7.4 years ( range , 6–8 years ) .  Clinical and radiographic followup was done using Knee Society and Hospital for Special Surgery knee rating systems at 6 weeks , 3 months , 6 months , 1 year after surgery , and yearly thereafter . Total knee score , pain score , mean functional score , and range of motion were comparable in both groups . Two knee replacements ( 2 % ) in one patient with AMK prostheses were revised because of complete wear of tibial bearing polyethylene . One knee replacement ( 1 % ) in one patient with an LCS prosthesis was revised because of dislocation of the medial tibial bearing polyethylene and one knee replacement ( 1 % ) in one patient with an LCS prosthesis was revised because of complete wear of the medial tibial bearing polyethylene . No knee had aseptic loosening or osteolysis in either group . After a minimum followup of 6 years , the results of fixed- and mobile-bearing total knee prostheses in the current series are favorable . However , there is no evidence to prove the superiority of the mobile-bearing total knee design This study determined how ceramic-on-ceramic bearing THA affected joint-specific pain , function and stiffness in the first five postoperative years compared with ceramic-on-highly-crosslinked-polyethylene bearing THA .  Subjects less than 61 years of age were r and omized  to ceramic-on-ceramic ( CERAMIC ) [ n = 48 ] or ceramic-on-highly-crosslinked-polyethylene ( POLYETHYLENE ) [ n = 44 ] bearing THA . Subjects were assessed using the Western Ontario McMaster Osteoarthritis Index ( WOMAC ) and the R AND 12-Item Health Survey ( R AND -12 ) preoperatively , and at one and five years postoperatively . 92 subjects(50 ( 54 % ) males ; average age = 52 ( SD 6.6 ) years ) were enrolled . 78 ( 85 % ) subjects returned five years postoperatively . All subjects reported improvements at one and five years in all measured indices with no group differences detected . Seven ( 8 % ) subjects experienced postoperative THA complications , none related to bearing surfaces ; two subjects ( POLYETHYLENE ) required revision for instability . Both bearing surfaces provided excellent short-term results in younger subjects
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 ) .