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Avantage Cup has been widely used in dual mobility implants. However, in Swedish Registry, the outcome of the Avantage Cup is reported with higher implants revision compared to control. The aim of our study was to verify if the same results are present in the Registry of Prosthetic Orthopedic Implants (RIPO) of Emilia Romagna (ER, Italy), as the Avantage cup was the most implanted dual mobility cup for a long follow-up reported in this Registry (2000–2012). Furthermore, we assessed the survival rate of the implant over the time. We included all patients that underwent a primary THA using the Avantage cup during the period 2000–2020 in RIPO Registry. The survivorship of the primary THA implants was calculated and plotted according to Kaplan-Meier method. 886 Avantage cups were included in the analysis. During the observational period 44 hips were revised. The most common reasons for revision were: periprosthetic fractures (PPF) (n = 7, 0.8 %), deep infection (n = 7, 0.8 %), and cup aseptic loosening (n = 13, 1.5 %). The survival rate of the implant was 96.8 % (95.3–97.8) at 5 years, 95.7 at 10 years (94.0–97.0) and 92.1 at 15 years (88.5–94.6). In conclusion, this study has demonstrated that the Avantage cup in primary hip arthroplasty implanted with a "friendly" femoral stem granted satisfactory long-term survival. Therefore, in the Swedish Registry, the cause of the poor results presented for Avantage Cup could be the thick, rough neck stem of the widely used Lubinus stem. [ABSTRACT FROM AUTHOR]

Purpose: Templating is the first step in achieving a successful total hip arthroplasty. We hypothesize that native head size is highly correlated with implanted cup size. Therefore, the purpose of this study is to look for a correlation between sizes of the intra-operative measurement of the femoral head and the implanted cup. Methods: This is a monocentric observational study conducted from December 2018 till January 2023. All patients admitted for a primary total hip arthroplasty were included and retrospectively reviewed. Intra-operative femoral head measurement, radiographic femoral head diameter, templated (planned) cup size, and definitive implanted cup size were recorded. Results: The sample included 154 patients (85 female and 69 males) with a mean age of 66.2 ± 10.4 years. There were 157 THA cases; 82 on the right side and 75 on the left side. The native head size and acetate template on digital radiographs were the most significantly positively correlated with cup size (P < 0.0001) while the radiological head size was significantly negatively correlated with cup size (P = 0.009). The implanted cup was on average 2 ± 2 mm bigger than the native head size measured intra-operatively. Conclusion: The native femoral head diameter measured intra-operatively is a simple and reliable tool to help the surgeons choose the proper size of the acetabular cup, preventing complications during surgery hence optimizing results post operatively. This technique would contribute to a more ecofriendly orthopaedic reconstructive surgery. [ABSTRACT FROM AUTHOR]

The use of 3D-printed highly porous titanium acetabular cups in total hip arthroplasty (THA) is increasing. The porosity and mechanical properties of such highly porous titanium structures mimic those of natural cancellous bone, possibly allowing biological implant fixation to be improved. Recently, a 3D-printed highly porous Dual Mobility (DM) monobloc construct fully manufactured using Ti6Al4V alloy, with a titanium–niobium nitride (TiNbN) ceramic coating on the articular side to allow articulation against the mobile liner by improving the titanium vs. polyethylene tribological behavior, was introduced in THA. To the best of our knowledge, this is the first highly porous titanium monobloc DM implant on the market. The reasons for using a Ti alloy highly porous DM are multifarious: to prevent any possible adverse reactions due to the corrosion of Cobalt–Chromium–Molybdenum Alloy (CoCrMo) and Stainless Steel (SS) implants and to improve implant primary and secondary stability, particularly in cases of poor bone quality. Finally, with the introduction of an inner TiNbN ceramic coating surface, it was possible to overcome the poor tribological quality of titanium. Another interesting characteristic is this material's higher implant radiolucency, which might facilitate the radiographic assessment of cup orientation, which can, in turn, facilitate the detection of any intraprosthetic dislocation (IPD) and the measurement of polyethylene wear, which is very important in the study of the durability of THA. [ABSTRACT FROM AUTHOR]

Objective: The dual mobility cup (DMC) is designed to extend the longevity of the prosthesis by improving stability, enhancing the range of motion, and decreasing impingement without increasing wear. We hypothesized that DMC would reduce the risk of dislocation in elderly patients. This study aimed to investigate the clinical and radiographic outcomes of DMC‐total hip arthroplasty (THA) in elderly patients at high risk of dislocation. Methods: From June 2016 to March 2020, 94 patients with a mean age of 77.7 years (97 hips) who underwent a posterolateral approach for DMC‐THA in our department were followed up for at least one year. Preoperative and postoperative pelvic tilt angles (PTA) and DMC orientation were prospectively collected for all patients. Intraoperative and postoperative complications were recorded. A parametric test was used for normal distribution, and a non‐parametric test was used for non‐normal distribution. Results: Abduction and anteversion angles of the cup were 42.4 and 18.0° in the supine position immediately postoperative. The average PTA for patients in the supine and standing positions were 26.5 and 34.5°, respectively. When moving from the supine to the standing position, patients experienced a mean posterior pelvic tilt of 9°. No intraoperative acetabular‐related complications were recorded. Postoperative complications included early infection in one patient (1.0%) and dislocation in one patient (1.0%). Conclusion: Our study demonstrates that DMC‐THA provides satisfactory short‐term outcomes in elderly patients at a high risk of dislocation, regardless of the change in PTA resulting from postural transition. [ABSTRACT FROM AUTHOR]

Background: Instability is a common complication following total hip arthroplasty (THA). The dual mobility cup (DMC) allows a reduction in the dislocation rate. The goal of this systematic review was to clarify the different uses and outcomes according to the indications of the cemented DMC (C-DMC). Methods: A systematic review was performed using the keywords "Cemented Dual Mobility Cup" or "Cemented Tripolar Cup" without a publication year limit. Of the 465 studies identified, only 56 were eligible for the study. Results: The overall number of C-DMC was 3452 in 3426 patients. The mean follow-up was 45.9 months (range 12–98.4). In most of the cases (74.5%) C-DMC was used in a revision setting. In 57.5% DMC was cemented directly into the bone, in 39.6% into an acetabular reinforcement and in 3.2% into a pre-existing cup. The overall dislocation rate was 2.9%. The most frequent postoperative complications were periprosthetic infections (2%); aseptic loosening (1.1%) and mechanical failure (0.5%). The overall revision rate was 4.4%. The average survival rate of C-DMC at the last follow-up was 93.5%. Conclusions: C-DMC represents an effective treatment option to limit the risk of dislocations and complications for both primary and revision surgery. C-DMC has good clinical outcomes and a low complication rate. [ABSTRACT FROM AUTHOR]

Background: The use of dual mobility cups (DMC) has been shown to reduce hip instability after revision surgery. For severe acetabular bone loss, reconstruction with a Kerboull cross-plate and bone allograft would contribute to restoring native hip position and bone stock. Only two papers reported on the combination of Kerboull cross-plate with bone allograft and cemented DMC in revision total hip arthroplasty (THA).Methods: This is a monocentric retrospective study (28 cases) of first-time revision THA using such a construct in American Association of Orthopaedic Surgeons (AAOS) grade III and IV acetabular bone defect. Detailed demographic, clinical and radiographic results were recorded and evaluated.Results: With a mean follow-up of six ± 3.63 years, no case of instability was reported. The modified Harris Hip Score (mHHS) was 88.4 ± 10.1. No hook fracture or mechanical failure was observed. Non-progressive radiolucent lines were recorded. Osteointegration of the allografts was observed in all cases with a mean Grodet score of 7.9 ± 0.97.Conclusions: In first revision THA, the use of a Kerboull cross-plate with allograft and a cemented DMC in AAOS grade III and IV acetabular bone defects demonstrated excellent clinical and radiological outcomes with no recorded cases of dislocation or mechanical failure. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate polyethylene (PE) damage and wear lesions to the chamfer of mobile components under mobile and fixed femoral neck impingement at the third articulation, and to determine which femoral neck characteristics should be considered with a dual mobility cup to limit those lesions.Methods: Two femoral neck geometries (cylindrical and quadrangular) with two surface finishing roughness (rough and polished), and two head-to-neck ratios (28- and 22.2-mm diameter femoral heads) were evaluated in a hip simulator testing. For each characteristic, six femoral necks were tested with six dual mobility cups under fixed and mobile femoral neck impingement conditions. Chamfer PE damage and volumetric wear were evaluated and compared for each femoral neck characteristic and impingement condition.Results: Under mobile impingement condition, femoral neck characteristics did not significantly affect PE damage and wear lesions to the chamfer (p = 0.283 to 0.810). However, under fixed impingement condition, significantly higher PE damage and wear lesions to the chamfer were produced by the quadrangular geometry compared to the cylindrical geometry (p = 0.004 to 0.025). In addition, with the quadrangular geometry, rough surface finishing was demonstrated to increase volumetric wear of the chamfer (p = 0.009). No significant influence of head-to-neck ratio was observed on PE damage and wear lesions to the chamfer (p = 0.244 to 0.714).Discussion: This biomechanical study emphasized that femoral neck characteristics are critical with dual mobility cup and tend to favor a cylindrical geometry particularly whether fixed impingement at the third articulation occurs. [ABSTRACT FROM AUTHOR]

Although total hip arthroplasty (THA) has shown successful results, instability remains a major complication. In recent years, dual mobility cups (DMC) have gained interest among clinicians thanks to its low rate of dislocation and good clinical results. The main aim of this work was to describe the accuracy of data on DMC from national and regional joint registries (JRs) and the available worldwide literature. We identified topics on DMC among JRs to propose a new harmonized and standardized section for DMC with the aim to understand its surveillance over the time. We extracted survival and implant data for a separate analysis. After performing a critical exclusion process, nine JRs were considered eligible and included for final synthesis; these were the results from the available worldwide data from JRs. In our study, eight analyzed JRs reported a slight increase in DMC use in the last decade. In all the JRs evaluated and the available articles, dislocation remains one of the main reasons for revision and re‐revision in hip arthroplasties. DMC is considered to be a valid construct increasingly used worldwide in primary and revision THA with the primary aim of reducing dislocation rates. Annual reports from JRs collect heterogeneous and low‐quality information about outcomes and surveillance of DMC, creating a burden for clinicians to extract comparable data from different JRs. Longer follow‐up and a systematic registering of DMCs with international registry harmonization are needed to monitor DMC outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Concerns remain about potential increased wear with dual mobility cups related to the multiple articulations involved in this specific design of implant. This finite element analysis study aimed to compare polyethylene (PE) wear between dual mobility cup and conventional acetabular component, and between the use of conventional ultra-high molecular weight PE (UHMWPE) and highly cross-linked PE (XPLE).Methods: Patient-specific finite element modeling was developed for 15 patients undergoing primary total hip arthroplasty (THA). Five acetabular components were 3D modeled and compared in THA constructs replicating existing implants: a dual mobility cup with a 22.2-mm-diameter femoral head against UHMWPE or XLPE (DM22PE or DM22XL), a conventional cup with a 22.2-mm-diameter femoral head against UHMWPE (SD22PE) and a conventional cup with a 32-mm-diameter femoral head against UHMWPE or XLPE (SD32PE or SD32XL).Results: DM22PE produced 4.6 times and 5.1 times more volumetric wear than SD32XL and DM22XL (p < 0.0001, Cohen's d = 6.97 and 7.11; respectively). However, even if significant, the differences in volumetric wear between DM22XL and SD32XL as well as between DM22PE and SD22PE or SD32PE were small according to their effect size (p < 0.0001, Cohen's |d|= 0.48 to 0.65) and could be therefore considered as clinically negligible.Conclusion: When using XLPE instead of UHMWPE, dual mobility cup with a 22.2-mm-diameter femoral head produced a similar amount of volumetric wear than conventional acetabular component with a 32-mm-diameter femoral head against XLPE. Therefore, XLPE is advocated in dual mobility cup to improve its wear performance. [ABSTRACT FROM AUTHOR]

Background: The "cup-in-cup" technique allows for revision of failed total hip arthroplasty (THA) when the cementless cup is well fixed. Furthermore, it can be used for liner wear or mechanical failure where liner replacement may be impossible or impractical. Recently, the "cup-in-cup" technique in combination with dual mobility cups (DMC) has drawn increased attention. Our aim was to report on the clinical and radiographic outcomes following this surgery.Methods: From 2015 to 2020, 33 patients treated with the DMC- "cup in cup" technique were retrospectively reviewed. Fourteen patients had died while 19 were available for the final follow-up (FU), of which 15 underwent both a radiograph and a FU visit, 2 underwent a radiograph only and 2 underwent a telephone interview only. Patient-related outcome measures included the HHS and the WOMAC. Radiographs were assessed for implant loosening and positioning. Primary endpoint was revision of any cause and secondary endpoint was loosening of the DMC at the latest FU. The survival analysis was conducted using the Kaplan-Meier method.Results: The mean age at surgery was 78.6 ± 7.1 (63-93) years and the mean surgery duration was 124.4 ± 52.0 (60-245) minutes. Recurrent dislocation (42.4%), periprosthetic fracture (39.4%) and polyethylene wear (6.1%) were the most frequent reasons for surgery. The mean FU duration (n = 19) was 28.5 ± 17.3 (3-64) months. The mean HHS score at FU was 59.4 ± 22.2 (29-91) and the mean WOMAC score was 59.7 ± 25.6 (15.6-93.8). Two cups were revised due to instability and one revision was performed due to periprosthetic joint infection, accounting for an overall cup survival rate of 86.8% after a mean FU of 22.9 ± 18.0 (1.5-64.6) months. The survival rate free of loosening was 90.9% after a mean FU of 22.3 ± 18.5 (1.5-64.7) months.Conclusions: We found that the cementation of a DMC in a well-fixed cup is a promising short- to mid-term treatment addressing THA instability especially in elderly and frail patients, who benefit from a reduced operation time. Proper cementation technique, adequate cup positioning as well as selection of a sufficiently large DMC are crucial for treatment success. Longer FUs will be needed in the future in order to further prove the benefit of this technique. [ABSTRACT FROM AUTHOR]

Background: Proximal femoral fractures are considered a common problem in the elderly. Osteoporosis and the risk of fall especially in old age add to the complexity of management of these types of fractures. These fractures can be managed with different types of implants e.g. Dynamic hip screw, proximal femoral nail, proximal femoral plate, etc.. Aim of the Work: Prospective clinical trial study to assess the role of dual mobility unconstrained acetabular components in preventing and treating instability. Patients and Methods: In the period between December 2014 to April 2017 a prospective study was conducted involving 25 patients with high risk of dislocation underwent total hip replacement using dual mobility cup either as primary hip arthroplasty or revision hip arthroplasty. All cases were operated upon in Ain Shams University Hospitals and the follow up of the cases was 1 year. Results: There were no cases of prosthesis dislocation or loosening. There were only two cases of superficial wound infections who improved with wound debridement. Studies showed that the dual mobility cup did a great success in reduction in the risk of dislocation in specific conditions as patients with polio and other neuromuscular disorders and other risk factors for head dislocation. Conclusion: Conversion of a failed implant to a total hip implant is a good and safe option in treatment of such cases. Dual mobility cups decreased the risk of dislocation in such cases with increased longevity of the prosthesis and a considerably accepted range of motion of the hip joint. [ABSTRACT FROM AUTHOR]

Introduction: Dual-mobility cups (DMC) are currently used in patients having risk factors of instability. Most of the studies report the use of DMC in patients having a single high-risk variable. The aim of the study was to analyse a continuous series of patients treated with primary total hip arthroplasty (THA) and DMC with different high risk for dislocation. Methods: This is a retrospective study analysing the outcomes of primary THA with DMC in patients at high-risk of dislocation. The sample consisted of 215 patients having 1 of 3 aetiologies or risk factors: (1) young subjects (<55 years); (2) osteonecrosis of the femoral head (ONFH); and (3) femoral neck fracture (FNF). Results: With a mean follow-up duration of 70 ± 24.7 months, the findings showed the following: 2 patients had dislocated their hip following motor vehicle accidents; 1 patient had a traumatic femoral peri-prosthetic fracture; and 1 patient had an acute infection. No intra-prosthetic dislocation or aseptic loosening were encountered. No radiolucent lines were observed on the acetabular side. The mean modified Hip Harris Score was 96.6 ± 7.4%. Out of 186 patients, 170 (90.1%) would label their operated hip as a "forgotten hip". 78 out of the 84 patients (92.8%) who used to practice oriental sitting and/or ablution for prayers were able to return to their usual daily activities of extreme hip position and 74 out of the 84 patients (88%) described their operated hip as "a forgotten hip". No correlation was found between any of the studied variables. Discussion: The findings of this series of patients at high risk of dislocation showed excellent clinical and radiological results with very few complications. The use of DMC seems to counteract the impact of some aetiologies/risk factors that could lead to higher instability. Most patients practising extreme hip positions resumed their usual practices. [ABSTRACT FROM AUTHOR]

Purposes: Acetabular fractures are more and more common in the elderly. Open reduction and internal fixation (ORIF) may lead to poor outcomes and high revision rates. Primary total hip arthroplasty (THA) combined with internal fixation, also known as the combined hip procedure (CHP), associated with dual mobility cup (DM-CHP) could be an efficient procedure in selected elderly patients. The aim of this study is to compare functional and radiological outcomes between ORIF and DM-CHP. Methods: Between 2007 and 2018, 51 patients older than 65 years were surgically treated for acetabular fractures. Twenty-six patients were treated by DM-CHP and 25 by ORIF. Each group was divided into two subgroups regarding a single or combined approach. Hospital stay, surgical time, intraoperative blood loss, and complications were documented. The Harris Hip Score (HHS) was used for measuring the functional outcome. Radiological analysis was used to assess the centre of rotation in the DM-CHP group. Results: Median surgery time and intra-operative blood loss were higher in DM-CHP than those in ORIF. Early medical complication rate was higher for a combined approach as compared with a single posterior approach in DM-CHP (p = 0.003). Dislocation rate was 7.7% in DM-CHP. Revision rate was higher in ORIF (20% versus 7.7%). HHS was similar in both groups. Conclusions: DM-CHP leads to similar functional outcomes and less revision than ORIF. This study strengthens the practice of using only the posterior approach for primary THA in the elderly. Dual mobility is a valid therapeutic option for acetabular fractures in elderly patients. [ABSTRACT FROM AUTHOR]

Background: Limiting the risk of dislocation is one of the main aims of both dual mobility and Lefèvre retentive cups. However, these devices have never been compared. The goal of our study was to compare these devices in total hip arthroplasty revisions for instability. The judgement criterion was non-recurrence of dislocation in a follow-up period of eight years.Methods: This retrospective case-control study compared two continuous paired series of total hip arthroplasty revisions for instability. These series included 63 patients and 159 patients with implantation of a Lefèvre retentive cup and a dual mobility cup, respectively.Results: The success rate at eight years (i.e., no recurrence) was 91 ± 0.05% and 95 ± 0.02% in the Lefèvre retentive cup and dual mobility groups, respectively. The difference was not statistically significant (p = 0.6).Conclusion: It seems that the Lefèvre retentive cup provides comparable outcomes with the dual mobility cup in the total hip arthroplasty revisions for instability, avoiding recurrence in long term. [ABSTRACT FROM AUTHOR]

Background: Patients undergoing primary total hip arthroplasty (THA) with prior lumbar spine fusion (LSF) are a high-risk group for instability with reported incidence of dislocation as high as 8.3% using fixed bearing femoral heads. Purpose of this study was to determine risk of post-operative instability in patients undergoing primary THA with a history of prior LSF using dual mobility acetabular cups.Methods: This was a multicenter retrospective study with 93 patients undergoing primary THA using a dual mobility cup with a prior history of instrumented LSF. There were 56 females and 47 males with an average age of 66 years (46-87) and average BMI of 30 with mean follow-up of 2.7 years (range 12-124 months). Surgical approach included posterior (63), direct lateral (15), anterior (11), and direct superior (4). Forty-four percent had one level lumbar fusion, 29% with two levels, and 15% with three or more levels fused. The primary outcome investigated was instability.Results: There were no cases of instability or prosthetic joint infection in this group of patients with prior lumbar spine fusion undergoing primary THA using a dual mobility cup. There was one intra-operative periprosthetic femur fracture and one case of aseptic acetabular cup loosening.Conclusion: Patients undergoing THA with prior LSF are at increased risk for instability due to loss of normal spinopelvic relationship. The use of dual mobility cups in patients with prior LSF undergoing primary THA appears promising with no cases of instability in this high-risk group of patients. [ABSTRACT FROM AUTHOR]

Background: The aim of this retrospective study was to evaluate the clinical, radiologic, and survival results of dual mobility (DM) sockets in revision total hip arthroplasty (THA) performed for instability versus revision THAs performed for other reasons.Methods: From a computerized database, we identified 84 revision THAs using a modern DM socket performed in 81 patients with a mean age of 71 years. Indication for revision was recurrent dislocation in 47 hips, and other reasons in the remaining 37 hips. A survivorship analysis according to the actuarial method was carried out on the entire series using revision for any cause, revision for dislocation, and radiological cup loosening revised or not, as the end points.Results: Of the 81 patients, twelve died, six were lost to follow-up, eight had been revised, and 55 patients (58 hips) were unrevised and alive at a mean follow-up of 6.4 years. Dislocation occurred in four of the 47 (8.5%) hips for which indication for revision was dislocation versus one of the remaining 37 (2.7%) hips [odds ratio = 3.4 (0.4-31.3), p = 0.07]. According to our criteria, three acetabular components of which one was revised were considered as loosened. When using revision for dislocation as the end-point, the survival rate at seven years was 90.4 ± 5.3% (IC95%, 79.9-100) in the 47 hips for which the indication for revision was dislocation versus 100% in the remaining 37 hips (log-rank, p = 0.5).Conclusions: The current study indicated that DM sockets represent an interesting solution to prevent dislocation in revision THAs at mid-term follow-up. [ABSTRACT FROM AUTHOR]

Introduction: The dual mobility cup (DMC) concept was proposed by Professor Gilles Bousquet in 1974. Its' aims were to prevent postoperative dislocation, restore the physiological range of motion of the hip, and reduce the stresses at the interface. Since it was created, this design has been modified multiple times to reduce the complication rate, improve implant survival, and expand the indications. Areas covered: The objective of this review is to discuss the advantages and disadvantages of this implant based on its 40-year history and also to propose a range of indications based on published results. This will provide surgeons with a complete overview of DMC. Expert commentary: Published studies on DMC confirm the low dislocation rate. Improvements made to DMC overtime have greatly reduced the complications related to wear, such as aseptic loosening and intraprosthetic dislocation (IPD). According to the literature, the indications have expanded and are no longer limited to revision surgery only. Long-term studies are needed before we can draw formal conclusions and consolidate these promising results. [ABSTRACT FROM AUTHOR]

Introduction: Mechanical failure due to dislocation, fracture and acetabular wear is a major complication associated with the use of spacers in the management of periprosthetic joint infection (PJI). We have developed a novel custom-made spacer in the setting of two-stage septic revision hip arthroplasty and present the preliminary results of our technique.Materials and Methods: Between May 2015 and November 2017, 30 patients underwent hip revision using the ENDO spacer technique in the setting of a two-stage septic exchange arthroplasty. The technique involves the dual mobility liner and the downsized stainless cemented straight stem in combination with antibiotic-loaded PMMA bone cement. The primary outcome measure was the overall spacer complication rate, particularly spacer dislocation. Furthermore, functional outcome using the Harris Hip Score (HHS) before spacer implantation and prior re-implantation was evaluated.Results: The mean age of the patients was 69.8 years (range from 45 to 85; SD = 9.9 years). No microorganisms were preoperatively found in 23 (76.7%) cases. Successful re-implantation was performed in all patients after a mean spacer duration time of 53.6 days (range 14-288 days; SD = 48.2). Spacer-related complications occurred in only two patients (6.7%). The HHS significantly improved from 34.0 (range 3-62; SD = 15.1) to 48.1 (range 11-73; SD = 15.7) (p = 0.0008).Conclusions: The ENDO spacer surgical technique is a feasible option in the treatment of periprosthetic joint infection (PJI), with a low dislocation rate. Furthermore, it allows early mobilization with the possibility of full-weight bearing. [ABSTRACT FROM AUTHOR]

Purpose: Total hip arthroplasty with a dual mobility cup (DMC) is a proposed alternative to the widely performed bipolar hemiarthroplasty (BHA) for treating displaced intracapsular femoral neck fractures (DFNF) in the elderly. However, the comparison between the two modalities has not been extensively conducted thus far.Methods: A retrospective cohort study was conducted with DFNF patients aged over 65 years who were treated either by BHA or DMC. After propensity matching each group comprised 84 patients (168 patients in total) and was analyzed using peri-operative and post-operative parameters.Results: Mean follow-up durations were 22.1 and 21.7 months in the BHA and DMC groups, respectively. The BHA group demonstrated significantly less intra-operative blood loss (p = 0.001) and a shorter length of operation (p < 0.001). However, there was no difference in one-year mortality (p = 0.773). The Harris hip score (HHS) was significantly higher (p = 0.018) in the DMC group. The dislocation rate was not different between the two groups (p = 1.000).Conclusion: In DFNF patients aged over 65 years, short-term observation showed DMC to be the preferred treatment over BHA with better clinical outcome, without disadvantages in mortality or dislocation rate. Further long-term investigations are recommended to strengthen these results. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to investigate the incidence of dislocation and specific complications of the dual-mobility cup.Methods: The arthroplasties involved 167 hips in 165 patients; 51 hips (30.5%) were in men and 116 (69.4%) were in women. The active articulation E1® dual-mobility cup (Biomet, Warsaw, IN, USA) was used, and the surgical approach was posterolateral in 120 hips and anterolateral in 47 hips.Results: Four (2.3%) dislocations were observed. Mean time of dislocation was 30.5 days post-operatively. Three incomplete reductions occurred during closed reduction. When comparing parameters between dislocation and no-dislocation groups, there were no differences in patient and surgical parameters. However, all dislocations occurred in patients with femoral neck fractures and in the posterolateral approach group.Conclusion: The incidence of dislocation in total hip arthroplasty (THA) using a dual-mobility cup was acceptable, and cup diameter of the dislocation group was substantially larger than that of no-dislocation group. Based on clinical outcomes of our study, we conclude that the dual-mobility cup is a reliable option in THA, and further studies are necessary. [ABSTRACT FROM AUTHOR]

Introduction and methods: From January 2004 to December 2008, 188 total hip arthroplasties were performed using a cemented dual mobility cup. 174 patients were available for final analysis. Their mean age was 76.8 (range 54-98 years). The mean follow-up was 7.7 years (range 5-10 years). Results: There were no dislocations. Survivorship rates of the femoral and acetabular components were 100% at a minimum of 5 years. At the latest follow-up, the mean Harris Hip Score significantly increased from 31.6 (only arthritic patients) points preoperatively to 84.5 points. No patients had progressive osteolysis, component migration, or loosening on radiographs. 2 patients presented with periprosthetic fractures treated conservatively. 2 patients presented with infection treated without implant removal and 1 patient presented with transient femoral palsy. Conclusions: The results of this consecutive series confirmed the good performance of the cemented dual mobility cup at mean 7.7 years follow-up with no revision and no dislocations. [ABSTRACT FROM AUTHOR]

Dual mobility cup (DMC) inserts reduce the risk of dislocation after total hip arthroplasty (THA). No available research has clearly delineated stability advantages of DMC inserts in primary and revision THA. We investigated: (i) the degree of change in the safe zone of the cup when a DMC insert is used compared to a fixed insert; (ii) the method of selecting candidates for a DMC insert without changing the position of the acetabular (cup) component during revision THA in frequent dislocation cases caused by implant impingement.~Background~Background~A model of the pelvis and femur was developed from computed tomography images. The safe zone was defined as the area in the acetabular component, over which conditions for stable range of motion were satisfied. The safe zone was calculated for both a fixed and a DMC insert over a predetermined range of 3-D motion, and the effect of increasing the anteversion position of the femoral component from 5° to 35° was quantified.~Methods~Methods~The lowest ratio of the area of the safe zone was about 4.9 at 20° anteverison of the femoral component. Safe zone of DMC inserts zone had increased stability of 10°-15° in both vertical and horizontal directions, compared to fixed inserts.A 5- to10-fold expansion of the safe zone can be expected with the use of DMC insert.~Results~Results~DMC insert could help to set the acetabular component more accurately in primary and revision THA.~Conclusions~Conclusions [ABSTRACT FROM AUTHOR]

Purpose: We report clinical and radiological outcome of a dual mobility cup (DMC) of 2nd generation after a minimum of ten year-follow-up (FU). The goal of this work was to compare the results of this DMC in patients aged less than 55 years and in patients aged more than 55 years.Methods: From 2000 to 2005, a prospective and consecutive series of 119 THAs with a cementless DMC of 2nd generation (GIROS) were performed in patients aged less than 55 years and 444 in patients aged more than 55 years.Results: The mean FU was 11 years (8 to 15 years). Survivorships (failure of both components or cup loosening) were not different between patients aged less than 55 years and patients aged more than 55 years. There was no dislocation. DEVANE classification, Harris, PMA and Oxford scores improved after THA but no difference could be found between between < 55 years and > 55 years patients.Conclusion: These results are better than those of first generation (BOUSQUET) DMC (77 % of survival rate at 20 years of FU). These results are in the same agreement than those of the literature: 99 % of survival rate at 14.2 years of FU for KERBOULL with a low friction arthroplasty and 96.5 % at ten years of FU for ceramic/ceramic bearing (R CHANA). The DMC for young patient is a relevant surgical option with no dislocation and excellent clinical results and survival rate at more than ten years of FU. [ABSTRACT FROM AUTHOR]

Aim: We hypothesize that a dual mobility cup can be safely used via the direct anterior approach, without increasing the risk of complications or incorrect positioning.Materials and Methods: This retrospective study compared 201 primary total hip arthroplasties using a dual mobility cup performed via direct anterior approach without a traction table, to 101 arthroplasties performed via posterolateral approach. Implant positioning, function scores, and early complications were recorded.Results: Implant positioning was appropriate in both groups, with a higher cup anteversion in direct anterior approach. The complications rates were similar in both groups, with no dislocation or infection.Conclusion: The direct anterior approach without traction table associated with a dual mobility cup does not increase the risk of complications or non-optimal positioning of implants. This strategy is interesting for patients with high risk of post-operative dislocation. [ABSTRACT FROM AUTHOR]

Purpose: Dual mobility cup (DMC) consists of a cobalt-chromium (CoCr) alloy cup articulated with a polyethylene (PE) mobile component capturing the femoral head in force using a snap-fit technique. This biomechanical study was the first to evaluate and compare the generation of cracks in the retentive area of DMC mobile components made of highly crosslinked PE (XLPE) or conventional ultra-high molecular weight PE (UHMWPE).Methods: Eighty mobile components designed for a 52-mm diameter Symbol® DMC (Dedienne Santé, Mauguio, France) and a 28-mm diameter femoral head were analyzed. Four groups of 20 mobile components were constituted according to the PE material: raw UHMWPE, sterilized UHMWPE, annealed XLPE and remelted XLPE. Ten mobile components in each group were impacted with a 28-mm diameter CoCr femoral head using a snap-fit technique. The occurrence, location and area of the cracks in the retentive area were investigated using micro-CT (Skyscan 1176®, Bruker, Aarsellar, Belgium) with a 35 μm nominal isotropic voxel size by two observers blinded to the PE material and impaction or not of the mobile components.Results: Compared to conventional UHMWPE, the femoral head snap-fit did not generate more or wider cracks in the retentive area of annealed or remelted XLPE mobile components.Conclusion: This biomechanical study suggests that XLPE in DMC could be a safe alternative to conventional UHMWPE regarding the generation of cracks in the retentive area related to the femoral head snap-fit. [ABSTRACT FROM AUTHOR]

Introduction: Since 1962, the low friction arthroplasty developed by Sir John Charnley has given us very good long terms results at more than 40 years follow up, but dislocation remains a major complication. The dislocation rate is a permanent risk during the life of the patient and the prosthesis, defined by J. Caton and D. Berry in 2004 as a cumulative risk. History and concept development: The concept of dual mobility was thought up by G. Bousquet, A. Rambert and J. Rieu in the 1970s (1974-1979). The first one in 1979 was called NOVAE and combined two articulations: one large and one smaller by a recruitement phenomenon increasing the jumps distance and so decreasing dislocation forces. In 2003, D. Noyer published the first paper about the «third articulation»: a true metal/PE bearing. Since 1996, twenty years after the first patent, many dual mobility cups have been developed with various fixation ways and various designs.Conclusion: Today with the same principles there are many differences for the «third generation» with excellent results at more than ten years FU with less than 1% to 2% dislocation rate in primary, revision, recurrent THA dislocation and THA after femoral neck fractures. [ABSTRACT FROM AUTHOR]

Purpose: Because of the improvement of medical therapy and the corresponding increase in life expectancy, orthopaedic surgeons are obliged to perform more wide resections rather than intramedullary stabilization nailing for patients affected by tumours of the hip compared to the past. Wide resection often causes joint instability, so prosthetic reconstruction presents a higher risk of dislocation than in primary osteoarthritis cases. The aim of the present paper is to classify the indications for the dual mobility cup (DMC) hip prosthesis based on the anatomic structures involved in the disease and to analyse the rationale to reduce the risk of dislocation.Methods: Indications were analyzed and classified based on all the cases in which the DMC prosthesis was used for reconstruction after hip resection in an oncological research hospital.Results: Four classes of indications were identified; for classes I and IV the indication for DMC prosthesis can be considered strong; for classes II and III the indications must be evaluated considering the specific case, based on life expectancy, performance status, presence of osteoarthritis, and availability of adjuvant local therapies. When the DMC prosthesis is indicated, the cup should always be cemented, either alone or with augmentation techniques, to decrease the risk of mobilization due to local disease progression.Conclusions: DMC can be a valid alternative in reconstruction of the hip after tumor removal; nevertheless, prospective, randomized studies are necessary to verify the real dislocation rate based on the entity of resection. [ABSTRACT FROM AUTHOR]

Introduction: Low friction arthroplasty (LFA) introduced by Sir John Charnley was the gold standard for many years. Dislocation and infection are the first causes for early revision. Late failures are polyethylene (PE) wear and loosening. Due to dislocation risk we slowly switched to the use of LFA with dual mobility cups (DMC). The purposes of this study are (1) to assess whether our changes have improved outcomes and (2) what is the new gold standard?Material and Methods: We selected from an observational registry of 1,091 cases of hybrid Charnley total hip arthroplasty (THA). The acetabular component was either DMC in 455 cases or fixed cup (FC) in 636 cases.Results: Three dislocations (0.6%) occurred in the DMC group (none revised). In the FC group 54 dislocated (8.49%) and 20 were recurrent and underwent revision (revision rate 3.14%). In the DMC group, five acetabular and three femoral revisions were performed (revision rate for loosening 1.7%). In the FC group 19 cases underwent acetabular revision, and five cases had femoral component revised (revision rate for loosening 3.7%).Discussion: Charnley's LFA has proven over 50 years of excellent survivorship. To decrease dislocation risk, one suggested increasing femoral head diameter. Gilles Bousquet proposed another way, namely, the DMC concept. Dislocation is no longer a critical issue with DMC as demonstrated in our series and main series. DMC in primary THA is still a subject of debate. Mid-term results do not demonstrate a higher rate of wear than LFA. What is the current gold standard? LFA was and is our current gold standard in association with a DMC. [ABSTRACT FROM AUTHOR]

Purpose: Instability following total hip arthroplasty remains a common and disabling complication. The dual mobility cup (DMC) allows a reduction in the dislocation rate. An increasing number of studies have been undertaken to better understand DMC long term outcomes and complications. The goal of this systematic review was to clarify its different uses and outcomes according to the indications.Methods: A comprehensive literature review was performed using the keywords 'dual mobility' and 'tripolar cup' with no limit regarding the year of publication. One hundred seventy six publications were identified.Results: Current literature shows that "contemporary" dual mobility cup are a significant indication to manage instability following primary and revision hip arthroplasty. Survivorship at midterm is comparable to other articulations for primary THA, but is more difficult to evaluate in revision. Intra-prosthetic dislocation, wear, and loosening are now uncommon with new generations of DMC.Conclusions: Compared to previous generations of DMC, the current "contemporary" DMC presents a significant improvement. Current literature reveals a tendency to increase the indications but further studies with long term follow up remain important to consolidate these findings. [ABSTRACT FROM AUTHOR]

Purpose: Although the natural history of dual mobility has been exclusively borne for 20 years by a single company (due to industrial ownership), the concept has undeniably been very widely popularised with nearly 40 cups on the French market which should be regarded as a weight bearing surface, both broadly and in their own right. However, within the same original idea, these implants are not all identical (design, material, fixation ect.).The aim of this work is to propose a classification of different dual mobility cups by distinguishing between thegeneral characteristics of a conventional cup and those particular to this type of implant.Methods: By comparison with a standard metal-back cup, dual mobility is based on at least one additional interface corresponding to the mobility of the polyethylene insert in the concavity of the acetabular cup called the outersurface. Design, constitutive material, fixation of the cup and characteristics of the retentive insert are analysed through the published results.Results: The complications associated, in particular, the intraprosthetic dislocation and to a lesser extent fixation failures undoubtedly condemned the dissemination of the dual mobility concept, as witnessed by the fact that despite the precedence of this 40-year old concept, the overriding majority of publications (more than 95%) have only appeared in the last ten years.Conclusion: The latest generation of dual mobility cups combines: 1) a cast chrome-cobalt alloy cup covered with a bilayer coating of porous titanium and hydroxyapatite for long-term press-fit fixation to 2) an insert designed to eliminate all of the risks of intraprosthetic dislocation, whilst keeping all of the elasticity properties of the polyethylene, which has demonstrated its medium and long term effectiveness on preventing instability by overcoming other complications. [ABSTRACT FROM AUTHOR]

Dual mobility cups are getting increasing interest for the prevention, but also in the treatment of THA instability. Nevertheless when a dislocation occurs the main issue remains the knowledge and the correction of the causes of dislocation, including reorientation of the components and soft tissues treatment. There are several options of alternative implants to DMCs including upsizing of the head, and constrained liners. The Authors present how to evaluate patients with THA instability, the advantages and the disadvantages of each procedure and their experience in the treatment of cases without DMCs during a five years' time period. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to investigate how the use of dual-mobility cups (DMCs) affected the risk of revision due to dislocation as well as overall risk of revision compared with a conventional total hip arthroplasty (THA) system in the short term.Methods: A total of 12,657 primary THAs were registered from the start of 2011 to the end of 2014. 620 THAs were with DMCs. For comparison, we included all registered THAs with Exeter cup and a cemented Exeter stem combined with 28-mm femoral head. Patients were followed up with respect to revision and/or death until 1 January 2016. For survival analysis, we used revision as an endpoint. Cox proportional hazards models were used to analyse the influence of various covariates (age, gender, surgical approach, THA model and pre-operative diagnosis).Results: Of the 620 dual-mobility THAs and 2170 Exeter THAs, 100 had been revised. The overall unadjusted cumulative revision rate (CRR) for any reason of revision at five years after surgery was 3.9% in the dual-mobility group and 5.2% in the Exeter group. Cox regression analysis, adjusting for age, gender, THA type, surgical approach and pre-operative diagnosis, showed that the risk of revision was less in patients operated with DMCs and in patients having their operation for osteoarthritis.Conclusion: The DM implant had a lower short-term complication rate than a conventional well defined THA. Low dislocation rate suggests that it is a good choice for high risk patients. [ABSTRACT FROM AUTHOR]

Dual mobility cups (DMC) in total hip arthroplasty (THA) are becoming popular among orthopaedic surgeons. Substantial benefit of their use has been reported among high risk patients, particularly in reducing post-operative hip instability (dislocation). Many reports stated some concern when implanted in young and active people where complications such as polyethylene wear and mechanical loosening could potentially be higher. This Middle Eastern study analyses a retrospective series of THA for any aetiology other than infection, using DMC for the acetabular component in 75 patients (85 implants) less than 70 years old. No instability, intra-prosthetic dislocation or mechanical failure was reported during a mean follow-up of five years. The only major complication was a post-operative infection. The mean post- operative modified Harris hip score was 97.1 out of 100. All patients resumed their daily activities and all religious practicing patients were able to accomplish their prayer positions without pain. DMC is found to be an interesting option in reducing dislocation events in young patients. Those excellent short-term results would encourage surgeons to use DMC in an active and highly demanding population. Further research is necessary to confirm maintenance of such results at long term follow-up. [ABSTRACT FROM AUTHOR]

Background: A dual mobility cup has the theoretic potential to improve stability in primary total hip arthroplasty (THA) and mid-term cohort results are favorable. We hypothesized that use of a new-generation dual mobility cup in revision arthroplasty prevents dislocation in patients with a history of recurrent dislocation of the THA. Materials and methods: We performed a retrospective cohort study of patients receiving an isolated acetabular revision with a dual mobility cup for recurrent dislocation of the prosthesis with a minimum follow-up of 1 year. Kaplan-Meier survival analyses were performed with dislocation as a primary endpoint and re-revision for any reason as a secondary endpoint. Results: Forty-nine consecutive patients (50 hips) were included; none of the patients was lost to follow-up. The median follow-up was 29 months (range 12-66 months). Two patients died from unrelated causes. Survival after 56 months was 100 % based on dislocation and 93 % (95 % CI 79-98 %) based on re-revision for any reason. Radiologic analysis revealed no osteolysis or radiolucent lines around the acetabular component during the follow-up period. Conclusion: The dual mobility cup is an efficient solution for instability of THA with a favorable implant survival at 56 months. Level of evidence: Level 4, retrospective case series. [ABSTRACT FROM AUTHOR]

Purpose: Total hip arthroplasty (THA) as primary treatment for displaced femoral neck fractures is controversial as THA is associated with higher rates of dislocation but lower rates of re-operation compared to hemiarthroplasty (HA). A dual mobility cup (DMC) design is associated with lower dislocation and re-operation rates in elective surgery. Is this also the case when used to treat displaced femoral neck fractures? The aim of this study is to compare rates of dislocation and re-operation of any kind following treatment for displaced femoral neck fractures with either bipolar HA or THA with DMC. Methods: Two consecutive groups of patients treated for displaced femoral neck fractures at the Regional Hospital in Viborg in Denmark were included. In 2007-2008 171 patients (mean age 84.1 years) were treated with bipolar HA. In 2009-2010 175 patients (mean age 75.2 years) were treated with THA with DMC. Data regarding rates of dislocation and re-operation were obtained by retrospective review of medical records. Results: We found a statistically significant difference regarding rates of dislocation and re-operation of any kind in favour of THA with DMC. Dislocation occurred in 25/171 patients [95 % confidence interval (CI) 9.3-19.9 %] treated with bipolar HA and 8/175 patients (95 % CI 1.5-7.7 %) treated with THA with DMC ( p = 0.002). Re-operations were required in 32/171 patients (95 % CI 12.9-24.6 %) treated with bipolar HA and 16/175 patients (95 % CI 4.8-13.4 %) treated with THA with DMC ( p = 0.01). Conclusions: Our findings indicate that THA with DMC is superior to bipolar HA following treatment for displaced femoral neck fractures in regard to rates of dislocation and re-operation. [ABSTRACT FROM AUTHOR]

Purpose: Mid- and long-term follow-up of Charnley total hip arthroplasty (THA) demonstrated good functional results with 85 % survivorship at 25-year follow-up. However, dislocation still remains an unsolved problem. Dislocation may occur throughout the patient's and implant's life. The aim of this study is to answer the question: does a dual mobility cup (DMC) decrease the dislocation risk? Methods: We report comparative results at ten years of follow-up of two groups of primary cemented Charnley-type THA, one with a standard polyethylene cup (group 1, n = 215) and the other one with a DMC (group 2, n = 105). Results: In group 1, 26 dislocations (12.9 %) occurred. In group 2 only one dislocation (0.9 %) occurred. This dislocation was successfully reduced by closed reduction, without any recurrence. This difference was statistically significant ( p = 0.0018). In group 1, the reason for revision was recurrent dislocation in 21 cases. Five patients were revised for other reasons. The global revision rate was 12.9 %. In group 2, two patients needed revision surgery for aseptic loosening. The global revision rate was 2.1 %. This difference was statistically significant ( p = 0.054). The goal was reached for the patients of group 2 who had more risks factors for dislocation (age, aetiology, American Society of Anesthesiologists and Devane scores) than those of group 1. Conclusions: When using a DMC, we observed a low rate of dislocation in primary THA (0.9 %). This surgical choice seems to be a safe and effective technique in Charnley-type THA, especially in a high-risk population. [ABSTRACT FROM AUTHOR]

Purpose: The dual mobility cup introduced in France by Gilles Bousquet has been used in total hip replacement in high-risk patients. This device acts as a large ball implant and significantly reduces the risk of dislocation following hip arthroplasty. Published French literature has focused on low rates of dislocation and long-term follow-up similar to the low-friction arthroplasty. Methods: We retrospectively reviewed a continuous series of 105 cases of dual mobility cup Quattro (Groupe Lépine, Genay, France) implanted from 2000 to 2002. Selection of the patients requiring a primary hip replacement depended on risk criteria such as age, hip disease and activity score. The dual mobility cup was associated with a modular cemented femoral component and a 22.2-mm stainless steel head. Results: One dislocation occurred one month after the index surgery requiring no revision surgery. According to the Kaplan-Meier method, survival probability was 95.0 % (95 % confidence interval 81.5–98.8) at ten years of follow-up. Conclusions: Based on clinical outcome and patient assessment we conclude that the dual mobility cup is a reliable option to decrease dislocation risk without increasing polyethylene wear. [ABSTRACT FROM AUTHOR]

The aim of this paper was to assess the impact on stability of revision of 29 standard acetabular cups to press-fit uncemented dual mobility (DM) cups in THAs with recurrent dislocation. This series was composed of 17 women and 12 men aged on average 75.6 ± 8.1 years (55-88), operated on between November 2000 and July 2010. The average number of dislocations before revision surgery was 3.87 ± 1.79 (2-10), and the average time from primary procedure to revision was 6.6 ± 4.3 years (45-15 years). 9 patients (31.03 %) had already undergone one or more procedures for instability prior to revision to DM cup. All patients were reviewed at an average time of 46 ± 28 months (range: 17 months-11 years). Only one patient had redislocated in this time (3.4 %). This patient underwent a simple closed reduction and did not dislocate again. Level of evidence: IV retrospective cohort study. [ABSTRACT FROM AUTHOR]

Dislocation remains a major concern after hip arthroplasty. We asked whether dual mobility cups (DMC) would improve early hip stability in patients with high risk of dislocation. We followed 34 patients (21 females, 13 males) treated between 2009 and 2012 with cemented DMC for hip revisions caused recurrent hip prosthetic dislocation or as a primary procedure in patients with high risk of instability. Functional outcome and quality of life were evaluated using Harris Hip Score and EQ-5D respectively. We found that the cemented DMC gave stability in 94%. Seven patients (20%) were re-operated due to infection. One patient sustained a periprosthetic fracture. At followup (6 to 36 months, mean 18), the mean Harris hip score was 67 (standard deviation: 14) and mean EQ-5D was 0.76 (standard deviation: 0.12). We concluded that treating patients with high risk of dislocation with DMC can give good stability. However, complications such as postoperative infection can be frequent and should be managed carefully [ABSTRACT FROM AUTHOR]

Background: Total hip arthroplasty (THA) is considered one of the most successful surgical procedures providing pain relief and improvement of function in patients with end-stage hip arthritis that does not respond to non-operative treatments. As health care continues to improve and life expectancy increases, the demand for total joint replacement will grow to reflect this more active, aging population. Objectives: This study aims to review early complications of dual mobility cup arthroplasty. The objective is to perform a systematic review of early complications of dual mobility cup arthroplasty for primary and revision cases. Methodology: Types of studies we will include randomized control trails (RCTs), controlled clinical trials, retrospective cohort studies, and we will exclude case reports, case series studies, cross sectional studies, non English studies. Search results will be conducted to systematic review management software and manually screened for eligibility to be included. PRISMA flowchart will be produced based on the search results and the inclusion/exclusion criteria. We will search the MED-LINE database, PubMed, Cochrane Bone and Muscle Trauma Group Specialized Register, Cochrane Register of Controlled Trails (The Cochrane Library) using the following keywords related to: THA, Dual mobility cup, complications, intraprosethetic dislocation. Results: Early complication rate in dual mobility cups is significantly higher in revision cases compared to primary cases, with the exception of IPD which was significantly lower in revision cases. Early complication rate of conventional THA was significantly higher than both primary and revision dual mobility cups. Conclusion: Dual mobility THAs are a good alternative to traditional bearing surfaces with long survivorship and low rates of instability after primary and revision THA. The rate of complications which are unique to the procedure, including intraprosthetic dislocation, is relatively low and limited mainly to earlier designs. High-quality, prospective, comparative studies are needed to further evaluate the use of dual mobility in primary and revision THA. [ABSTRACT FROM AUTHOR]