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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.

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]

Revision total hip arthroplasty (RTHA) is a challenging procedure when we speak about acetabular defects and recurrent instability. There are multiple reasons like the number of previous revisions, implant position, bone quality, patient characteristics and etc. Managing acetabular defects with porous trabecular metal augments has excellent survivorship, but when addressing instability, there are some unsolved issues. Management options include the use of large femoral heads, constrained acetabular liners, and dual mobility cups (DMC). These cups have increased jump distance and reduced likelihood of dislocation while not relying on locking mechanisms, therefore are the preferred option in RTHA. We present single-center series of 13 patients undergoing revision THA with a specific DMC cemented into a newly implanted or well-fixed trabecular metal (TM) revision shell. All patients underwent cementation of a single specific cemented DMC design (Novae Stick, SERF, Decines, France) in a Trabecular Metal Revision Shell (Zimmer Biomet, Warsaw, IN, US). The mean follow-up is 15,2 months, and there were no dislocations of the implanted DM cups. The mean HHS improved significantly from 35.9 (range 15–80) preoperatively to 80.1 (range 64-93) postoperatively (p = 0.001). The results of this small clinical series demonstrate that cementing a DMC in a well-fixed TM revision shell leads to no dislocation or dissociation of the cement interface and acetabular construct loosening in the short term

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.

Cemented dual mobility cups (DMCs) are commonly used in combination with acetabular reinforcement devices. Indeed, according to literature, direct cementation of metal-backed acetabular components into the bony acetabulum remains controversial as this technique is potentially associated with increased rates of aseptic loosening. Therefore, this study aimed to evaluate the clinical and radiographic outcomes of DMC cemented into the bony acetabulum in primary total hip arthroplasty (THA). A total of 49 THA (48 patients, mean age 78 years [range, 51 to 91]) performed with direct cementation of a DMC into the bony acetabulum were prospectively included in our total joint registry and retrospectively reviewed. The clinical outcome was assessed using the Harris hip score (HHS). The radiographic outcome included measurement of component positioning and occurrence and progression of demarcation around the cemented DMC. Complications were reported with a particular attention to cemented fixation failure and aseptic loosening. At a 7-year mean follow-up (range, 5 to 8), the pre-to postoperative HHS improved from 47 (range, 30 to 58) to 92 points (range, 80 to 98) (P <.01). Nonprogressive and focalized demarcations were observed in 7 THA (14%). Importantly, no progressive demarcation or DMC aseptic loosening was observed. Direct cementation of DMC into the bony acetabulum ensured a stable fixation with no progressive demarcation or aseptic loosening at midterm follow-up. Therefore, this technique can be selectively considered in primary THA, especially in elderly or frail patients to avoid potential mechanical failure of press-fit fixation due to altered bone quality or additional morbidity related to the use of acetabular reinforcement devices. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to compare the revision rate and long-term survival between two generations of uncemented dual mobility cup (DMC) from the same manufacturer in primary total hip arthroplasty (THA) at a minimum follow-up of 10 years. Methods: This retrospective monocentric study included all THA performed with an uncemented DMC from the same company. The cohort included 150 patients with 22 first-generation DMC and 128 second-generation DMC. The coating of the second generation was a double-coating Plasma spray of Titanium and Hydroxyapatite (HAP), compared to the coating of alumina and HAP for the first generation. The mean follow-up was 14.2 ± 1.2 years. The mean age was 76.0 ± 10.1 years. The Harris hip score (HHS), complications, and revisions were collected at the last follow-up. Ten- and fifteen-year Kaplan-Meier survival was calculated. Results: At the last follow-up, the mean HHS was 83.2 ± 9.1. There were two acetabular loosenings with the old coating (9.1%) and one case with the new one (0.78%) (p = 0.056). There was one extra-prosthetic dislocation (0.67%) and one postoperative infection (0.67%). Survival without acetabular revision at 10 and 15 years was 90.9% for the 1st generation and 99.2% for the 2nd generation (p = 0.009). Conclusion: Survival without acetabular revision was significantly higher at 10 and 15 years of follow-up with the second generation of DMC with plasma-sprayed titanium and HAP coating compared to the first generation of DMC coat. The dislocation was uncommon, thanks to the dual mobility concept. This second generation of uncemented DMC can be safely used in primary THA.

Introduction: Performing total hip arthroplasty (THA) after failed internal fixation of proximal femoral fractures (PFF) is known to be associated with high rates of complications. Dual mobility cups (DMC) are known to lower dislocation events in high-risk patients. Very few reports investigated the outcomes of THA using DMC following failure of internal fixation for PFF. Methods: This is a retrospective monocentric continuous study of 31 patients who underwent THA with DMC after failed internal fixation of PFF. The clinical assessment was based on the modified Harris hip score (mHHS) at the last follow-up. The complication rates and radiological analyses were recorded. Results: The mean follow-up period was 5.96 ± 4.2 years. At the last follow-up, the mean mHHS was 92.9 ± 9.1 with 71% of the patients describing their operated hip as a forgotten hip. No dislocation or aseptic loosening events were noted. One patient developed a septic loosening of the implant. No significant radiological changes were recorded. Sixteen stems (51.6%) were placed in a neutral position, 13 (42%) in valgus (2.74 ± 1.72°), and 2 (6.4%) in varus (6.94 ± 2.02°). Conclusion: This study emphasizes the advantage of using DMC following failed internal fixation of PFF in reducing dislocation and complication events in this high-risk population.

Objective: Prosthetic joint dislocation remains a significant cause of revision following total hip replacement (THR). To prevent this complication, emphasis has been on choosing the optimum surgical approach, accurate implant alignment, bigger femoral head size, and implementing postoperative hip precautions. In the last decade, a newer acetabular design concept; the “Dual Mobility cup” (DM cup) was introduced to reduce the prosthetic dislocation. Although the concept of the use of such a device is well accepted, there remains apprehension regarding its precise indications, the outcome in terms of wear and ability to decrease the incidence of prosthetic dislocation. We reviewed the early results of a particular DM cup design. Materials and Methods: This study shares a single center experience of using a monoblock DM cup (Captiv DM, Evolutis, Briennon, France) in THR. It is a prospective cohort study that looked at indications, handling issues, complications including prosthetic dislocations at 24 months follow-up. Results: We followed up results of uncemented and cemented DM cup used in 129 patients who underwent primary THR or revision THR (RTHR). There was one (1.6%) prosthetic dislocation amongst primary THR and 2 (3%) in the RTHR group. There were handling issues with monoblock uncemented DM cups of occasional improper seating and acetabular rim fracture. Three cases in which revision was performed, were due to component to component impingement and resulted due to inappropriate acetabular version. Conclusion: The use of DM cups while performing THR or RTHR significantly decreased the incidence of instability. While placing DM cups an attempt should be made to maintain the native version of the acetabular cup to decrease the risk of component impingement and instability. Level of Evidence: Level III, therapeutic study.

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]

Background: A mobile polyethylene liner enables the dual mobility cup (DMC) to contribute to restoring hip joint range-of-motion, decreasing wear and increasing implant stability. However, more data is required on how liner orientation changes with hip joint movement. As a first step towards better understanding liner orientation change in vivo, this cadaver study focuses on quantifying DMC liner orientation change after different hip passive movements, using ultrasound imaging and motion analysis., Hypothesis: The liner does not always go back to its initial orientation and its final orientation depends mainly on hip movement amplitude., Methods: 3D ultrasound imaging and motion analysis were used to define liner and hip movements for four fresh post-mortem human subjects with six implanted DMC. Abduction and anteversion angles of the liner plane relative to the pelvis were measured before and after hip flexion, internal rotation, external rotation, abduction, adduction., Results: Liner orientation changes were generally defined by angle variation smaller than 5°, with the liner nearly going back to its initial orientation. However, hip flexion caused liner abduction and anteversion angle variations greater than 15°. Except for hip adduction, only weak or no correlation was found between the final angle of the liner and the maximal hip joint movement amplitude., Discussion: This study is the first attempt to quantify liner orientation change for implanted DMC via ultrasound imaging and constitutes a step forward in the understanding of liner orientation change and its relationship with hip joint movement. The hypothesis that the final liner abduction and anteversion angles depend mainly on hip movement amplitude was not confirmed, even if hip flexion was the movement generating the most liner orientation changes over 15°. This approach should be extended to in vivo clinical investigations, as measured liner angle variation could provide important support for the wear and stability claims made for DMC., Level of Evidence: IV; cadaveric study., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Abstract 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.

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]

Abstract Objective To evaluate the incidence of prosthetic instability in a consecutive series of 42 cases of total hip arthroplasty using dual mobility cup. Methods A retrospective study of 38 patients undergoing primary or revision total hip arthroplasty (THA) using the acetabular dual-mobility cup (DMC) implant between January 2012 and January 2018. The rates of complications and instability after surgery were evaluated. Results In total, 42 arthroplasties were performed in 38 patients, with a minimum follow-up of 16 months. The mean age of the sample was 60 years. In 38 cases, we used a cementless DMC, and, in the other 4 cases, a cemented DMC. There were no cases of early or late instability. Conclusion The series herein presented proves the good result of the DMC in cases of primary arthroplasty, complex and complicated cases of failed osteosynthesis of proximal femoral fractures, and revision for THA instability. The absence of episodes of prosthetic instability and complications in complex cases of primary and revision THA increases the confidence in this concept.

Abstract Background Total hip arthroplasty (THA) via the direct anterior approach (DAA) using dual mobility cup (DMC) is considered to effectively prevent postoperative dislocation. However, the dislocation and reduction procedure using a trial implant during the surgery is difficult because of high soft tissue tension. Thereby, leg length discrepancy (LLD) is difficult to assess when using DM via the DAA. Purpose To compare the LLD between cases using conventional SM and those using DMC in THA via the DAA with fluoroscopy. Patients and methods We retrospectively investigated 34 hips treated with DMC (DMC-DAA group) and 31 hips treated with SM (SM-DAA group). The LLD was defined as the difference in the distance from the teardrop to the medial-most point of the lesser trochanter between the operative and nonoperative sides at immediate postoperative X-ray. Results The mean LLD in the DMC-DAA group and SM-DAA group was 0.68 ± 7.7 mm and 0.80 ± 5.5, respectively, with no significant difference. The absolute value of the LLD in the DMC-DAA group and SM-DAA group was 6.3 ± 4.4 mm and 5.9 ± 5.5, respectively, with no significant difference. Conclusion Despite the difficulty in assessment of the LLD during THA via the DAA using DMC, this technique does not increase the LLD compared with the use of SM. Level of evidence III, matched case-control study.

Introduction: Dual mobility cups (DMC) are gaining in popularity, as a method to reduce the risk of dislocation after fracture-related hip arthroplasty. Our aim was to compare revision rate in general, as well as due to dislocation and infection, after DMC and conventional THA due to femoral neck fracture, for each of the two groups of lateral and posterior approach.Materials and Methods: This observational cohort study based on the Swedish Arthroplasty Register (SAR) compared 2242 patients with dual mobility cups (DMC) and 6726 with conventional total hip arthroplasty (cTHA), all due to acute fracture 2005-2019. This was after propensity score matching of 1:3 (age, gender, ASA). Kaplan-Meier survival analysis was used to investigate the 5-year revision rate after DMC and cTHA in the posterior and lateral approach groups.Results: The rates of revision in general, and due to dislocation or infection, were similar for DMC and cTHA in the different approach groups during the follow-up. The cumulative revision rate after posterior approach was 4.7% (95% CI 3.1-6.2) for DMC and 4.8% (3.8-5.7) for cTHA at 5 years. For lateral approach, the result was 2.3% (CI 1.3-3.3) for DMC and 3.7% (CI 3.0-4.4) for cTHA. The 5-year results for cumulative revision rate due to dislocation after posterior approach were 1.3% (0.4-2.2) for DMC and 2.2% (1.5-2.8) for cTHA. Corresponding results for lateral approach was 0.4% (0-0.8) for DMC and 0.7% (0.4-1) for cTHA.Discussion: With implant revision surgery as outcome, we could not detect any differences between DMC and cTHA. Further studies with high external validity are needed regarding total dislocation rate, patient-reported outcome, cost-effectiveness and learning curve, to make a definitive recommendation on the use of DMC for fracture cases.Conclusions: As treatment of acute femoral neck fractures, total hip arthroplasty with a dual mobility cup have similar outcome in terms of revisions in general, and due to dislocation or infections specifically, as one with conventional bearing. The similar outcome is regardless of surgical approach. [ABSTRACT FROM AUTHOR]

Introduction: Despite its excellent results in preventing dislocation, the dual mobility cup (DMC) is still struggling to be adopted by some teams due to premature wear and loosening reported on first-generation implants. Therefore, this study aimed to assess the mid-term survivorship of a modern DMC with a pre-impacted head and the radio-clinical results at a minimum follow-up of 5 years. Methods: This was a retrospective single-centre study performed on patients who had a primary total hip replacement for osteoarthritis in 2016. The cup was a third-generation DMC with a pre-impacted femoral head. Clinical (harris hip score (HHS)) and radiological (cup abduction, anteversion, overhang, and radiolucent lines) results were recorded, as well as complications, particularly dislocations and survivorship. A minimum of five years of follow-ups was required. Results: One hundred and seventy-five hips (167 patients) met the inclusion criteria. Five hips (2.9%, 5/175) were lost to follow-up and excluded from the postoperative analysis. The mean follow-up period was 70 ± 2.9 months [63.6–76.5]. Three cups needed revision surgery (1.8%, 3/170): one for septic loosening, and two for chronic infection. At 77 months, the global survival probability was 98.2% ± 1, and the survival probability excluding septic aetiology was 100%. There was a significant improvement in the HHS from pre-operatively (48.3 ± 6.0 [14.0–70.0]) to post-operatively (96 ± 4.5 [50–100]) (p

Introduction: The choice between hemiarthroplasty (HA) and total hip arthroplasty (THA) for displaced femoral neck fractures remains debated. There is increasing use in dual mobility cup total hip arthroplasty (DMC-THA) to prevent dislocations in these high-risk patients. Aim of this study is to retrospectively analyze patients treated in a single Center for femoral neck fracture comparing HA and DMC-THA in terms of: functional outcome, rate of complications and mortality., Material and Methods: Between 2020 and 2022, 162 patients were included, 39 male and 123 female, with a mean age of 76 years old. HA were implanted in 82 cases and DMC-THA in 80 cases. INCLUSION CRITERIA WERE: age < 85 years old, American Society of Anesthesiologists (ASA) score below 3, minimum follow-up of 6 months. Overall, 124/162 of patients (77%) were surgically treated within 48 h from admission., Results: The mean age for DMC-THA group was 74 years old and 78 years old for HA group. The overall mean surgical time was significantly higher in the DMC-THA group (P < 0.001). Mean hemoglobin (Hb) loss was 1.64 g/dl in the HA group and 1.72 g/dl in the DMC-THA group with no differences between the two groups (P = 0.573). There is no difference in survival of patients between the two groups (P = 0.7704). In the HA group, the mean one-month post-operative VAS score was 2.1, while in the DMC-THA group was 0.9. The Harris hip score was significantly better in DMC-THA group (P = 0.035) Dislocation never occured in the overall series. Infection occurred only in one patient with DMC-THA and was treated with debridement. Periprosthetic fracture occurred in 2 cases of DMC-THA both within 1 month from the first surgery; one was treated with revision femoral stem and the second one with fixation., Conclusions: DMC-THA offer better functional results than HA in elderly patients with femur neck fractures. The mean surgical time was longer in DMC-THA but this did not influence blood loss, time of discharge or one-year mortality. In our series dislocation never occurred in both groups., Competing Interests: Declaration of competing interest Pietro Ruggieri is Consultant and Designer for Stryker and Exactech. Each Author certifies that he or she has no commercial associations (e.g., consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

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: Although the antidislocation effect of total hip arthroplasty (THA) via the direct anterior approach (DAA) with dual mobility cup (DMC) for displaced femoral neck fracture (FNF) has already been reported, the clinical result of DMC-DAA-THA for displaced FNF in terms of mortality, complications, and walking ability are still unclear.Methods: 106 cases with DMC-DAA-THA for displaced FNF were investigated of dislocation; perioperative complications; 3-, 6-, and12-month mortality rate; and pre/early postoperative walking ability. The walking ability was stratified into the following four categories: (1) use of a wheelchair (no walking), (2) walking alongside a support (including walkers designed for the elderly), (3) walking using one stick, and (4) unaided walking.Results: There was no dislocation withing one-year postoperative. The 3-, 6-, and 12-month mortality rate was 2.8%, 4.7%, and 5.7%. Total complications occurred in 14 cases (14.7%). Although there was no revision surgery, two cases (1.9%) of intraoperative fracture treated without additional fixation, and one case of postoperative fracture was occurred. Among patients with preinjury walking category 2, 3, and 4 (total 94 cases), the number of patients who recovered same walking category at two-week postoperation was 56 cases (59.6%).Conclusions: Our study demonstrated that DMC-DAA-THA for displaced FNF offered quick recovery of walking ability with no dislocation and low one-year mortality rate. We believe that the combination of early postoperative recovery due to the minimal invasiveness of the DAA and decreased dislocation rate due to increased range of motion by DMC and adequate soft tissue tension by DAA contributed to null dislocation. [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]

Dual mobility acetabular cups (DMC) were designed to increase the effective femoral head size and improve stability with the goal of reducing revision risk at the potential cost of polyethylene thickness. We sought to evaluate revision risk following primary elective total hip arthroplasty with DMC compared to highly cross-linked polyethylene (XLPE). A cohort study was conducted using data from a Kaiser Permanente's total joint arthroplasty registry. Patients ≥18 years who underwent primary elective total hip arthroplasty using DMC, unipolar Metal-on-XLPE (MoXLPE), or unipolar Ceramic-on-XLPE (CoXLPE) were identified (2010 to 2021). The final sample comprised 2,219 DMC, 48,251 MoXLPE, and 57,058 CoXLPE. Multiple Cox proportional hazard regressions were used to evaluate aseptic revision and any dislocation regardless of revision within 6 years follow-up. In adjusted analyses, no differences in aseptic revision risk were observed for MoXLPE (hazard ratio [HR] = 1.04, 95% confidence interval [CI] = 0.72 to 1.51) or CoXLPE (HR = 0.98, 95% CI = 0.69 to 1.40) compared to DMC. No differences in dislocation risk were observed for MoXLPE (HR = 1.42, 95% CI = 0.93 to 2.15) or CoXLPE (HR = 1.25, 95% CI = 0.84 to 1.87) compared to DMC. In a US-based cohort, 6-year aseptic revision risk of DMC was similar to metal or ceramic femoral head unipolar constructs. Furthermore, no difference in dislocation risk was observed. Continued longer-term follow-up may reveal if there is a reduced risk of dislocation that comes at the cost of increased late revision. Level III. [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]

Dislocation is a common complication of Total Hip Replacement (THR), particularly when performed in primary (indications with increased risk of instability) and in revision scenarios. Dual mobility THR (DMTHR) minimizes the risk of instability in such scenarios, however most of the evidence is from western literature. Results of DMTHR in Indian scenarios where patient want to go back to their normal routine activities of squatting and sitting cross-legged is lacking. The aim of our study was to evaluate the short to mid-term results of DMTHR for varied indications (both primary and revision) in Indian scenario. To evaluate the outcome of the DMTHR in terms of functional range of motion and the ability to go back to their pre-injury level of activity. This is a retrospective study of 150 patients operated with DMTHR between January 2015 to February 2019 with a minimum follow-up of 12 months. Patients were evaluated clinically using Modified Harris Hip Score (HHS), Range of Motion (ROM), and Patient Reported Outcome Measures (PROM) like ability to squat and sit cross legged. Radiological evaluation was done using radiographs to assess loosening, stress shielding, osteolysis. Mean follow up in our study was 25.2 months (Range 12–46 months). Mean Modified HHS was 71.8 ± 8.11 at 6 weeks post-op and 85.8 ± 7.62 at last follow-up. HHS showed excellent outcome in 36 hips (26.7%), good outcome in 76 hips (56.7%), fair outcome in 20 hips (14.6%), poor outcome in 3 hips (2%). All our patients were allowed to squat and sit cross-legged at a mean follow-up period of 13 weeks (8 weeks–20 weeks) except 10 cases of Revision THR where patients were advised not to squat or sit cross-legged. All patients were able to resume their activities of daily living. DMTHR in patients of all ages has shown a good short to midterm clinical outcome which is comparable to conventional THR. It confers the benefit of stability allowing our patients to squat and sit cross legged which is often one of the expectation and requirement of a patient undergoing THR in India. DMTHR in both primary and revision scenarios exhibit a low risk of dislocation, complications and revision surgery. [ABSTRACT FROM AUTHOR]

PURPOSE: To assess the dislocation rate after total hip arthroplasty with dual mobility cup (DMC) for displaced femoral neck fractures and to compare the results with that of conventional total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHA) in the same clinical setting at our institution. MATERIALS AND METHODS: 49 cases (47 patients) treated with total hip arthroplasty with DMC, 38 cases (38 patients) with BHA and 29 patients (29 cases) operated on with conventional THA were retrospectively reviewed. RESULTS: In the DMC total hip arthroplasty group, there were no dislocations (0%). %). One dislocation (3,1%) occurred in the BHA group, and 3 dislocations occurred (11,1%) in the THA group. ). There was a statistically significant difference in favour of DMC group compared to THA group regarding dislocation rate (p=0,05). Dislocation rate did not differ significantly between DMC and BHA groups. There was no significant difference in mortality, complications and re-operation rate between groups. CONCLUSION: Dual mobility cups significantly reduce dislocation rate in total hip arthroplasty performed for displaced femoral neck fractures compared to conventional total hip arthroplasty while similar advantage over bipolar hemiarthroplasty could not be demonstrated in the current study.

Steffan Tabori-Jensen,1,2 Torben B Hansen,1,2 Søren Bøvling,1 Peter Aalund,1 Morten Homilius,1 Maiken Stilling1,2 1University Clinic for Hand, Hip and Knee Surgery, Regional Hospital West, Holstebro, Denmark; 2Department of Clinical Medicine, Aarhus University, Aarhus, Denmark Aims: Our aim was to investigate function, health status and satisfaction in patients treated with primary dual mobility (DM) total hip arthroplasty (THA) after displaced femoral neck fracture (FNF). Patients and methods: From 2005–2011, 414 consecutive FNF patients received Saturne DM THA. At a minimum of 1-year follow-up, 124 (95 women) were evaluated with Oxford Hip Score (OHS), Harris Hip Score (HHS), health-related quality of life (HRQoL) measure (EQ-5D) and two functional tests: Timed Up and Go (TUG) and Sit to Stand 10 times (STS). The FNF patients were matched 1:2 by age, sex and surgery date with patients receiving THA due to osteoarthrosis (OA group) and 1-year OHS and EQ5D were compared. FNF patients were matched by age and sex with the general population index (GPI) for EQ-5D comparison. Results: Patient age at surgery after FNF was mean 74.8 (range 30–92) years. At mean follow-up of 2.8 (range 1.0–7.7) years, mean EQ-5D score was 0.79 (SD 0.15) in the FNF group, which was similar to the matched GPI (p = 0.4), but lower (p = 0.014) compared to the OA group. Mean OHS was 36.4 (SD 9.5) in the FNF group and 38.4 (SD 7.2) in the OA group (p = 0.18). HHS in the FNF group was 78.7 (SD 15.5). Mean TUG time was 13.5 (SD 4.9) secs, and mean STS was 37.9 (SD 15.3) secs. Eighty nine percent (n = 111) of FNF patients were satisfied with the operation result. Conclusion: DM THA following displaced FNF provides a good functional result and quality of life in addition to high patient satisfaction. Keywords: dual mobility cup, femoral neck fracture, hip arthroplasty, EQ-5D, Oxford Hip Score, patient reported outcome measures

Background: Treatment of adverse local tissue reaction (ALTR) is challenging owing to high complications and poor outcomes after a revision surgery. As dislocation is the most common cause of reoperation, it is often necessary to use advanced articulations such as dual mobility. This study aims to evaluate the outcome and complication rates after revision surgery with dual mobility constructs, compared to constrained and conventional articulations in the setting of significant abductor deficiency due to ALTR.Methods: Out of a total of 338 revision total hip arthroplasties for ALTR, 234 patients with a significant tissue necrosis and abductor muscle insufficiency (grade 3) were evaluated. The complication rates after revisions were compared between 42 hips with dual mobility implants, 24 hips with constrained liners, 104 hips with large diameter heads (36-40 mm), and 64 hips with small diameter heads (≤32 mm).Results: After an average of 4 years of follow-up (2.8-8.6), the dual mobility articulation had no dislocation, compared to 4.1% and 15.5% for constrained liner and conventional articulations, respectively (P < .001). Utilization of dual mobility and constrained liner cup also did not increase the risk of nondislocation complications, including periprosthetic joint infection and periprosthetic fracture (P = .18 and .52).Conclusions: This study demonstrates significantly lower dislocation rates for dual mobility when compared to conventional articulations and comparable to constrained liners in cases of severe abductor deficiency due to ALTR, suggesting that dual mobility implants are viable surgical treatment alternatives to constrained liners to minimize dislocation during revision total hip arthroplasty in the setting of significant abductor deficiency due to ALTR. [ABSTRACT FROM AUTHOR]

Introduction: The incidence of heterotopic ossification after total hip replacement is variable in the literature. If symptomatic, it may cause pain and reduced range of motion. Dual mobility total hip replacements have been considered a valuable option for the treatment of femoral neck fractures in the active patients, achieving good range of motion with reduced risk of dislocation. The occurrence of HO may have detrimental effect on this type of articulation and may accelerate polyethylene wear and predispose to intra-prosthetic dislocation. We compared the incidence of HO in DMC versus conventional THR in femoral neck fracture patients across 3 large trauma institutes PATIENTS AND METHODS: This is a retrospective cohort study which included 334 patients, 223 received DMC replacements, 111 received conventional total hip replacement (THR). Mean age for the DMC group was 72.3 ± 9.9 years and was 72.1 ± 6.8 years for the THR group. Patients were stratified according to specific inclusion and exclusion criteria, and the 1-year follow up X rays were evaluated for the presence of heterotopic ossification by 3 assessors.Results: The incidence of HO in the DMC group was 27.1% compared to 12.2% in the THR group (χ2 p value = 0.0001, Relative Risk = 2.22, 95% CI 1.22-4.03, p value = 0.0091). There was no significant effect of gender or age on the incidence of HO in both groups CONCLUSIONS: Patients receiving DMC hip replacements are more likely to develop HO as compared to patients receiving conventional THR for femoral neck fractures. Further prospective studies are required to confirm our findings and to assess the indication of HO prophylaxis in patients receiving DMC hip replacements, and the long-term outcomes in these patients. [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]

Background: Revision total hip arthroplasty (rTHA) is a challenging surgery with a higher rate of complications than primary arthroplasty, particularly instability and aseptic loosening. The purpose of this study is to compare dual mobility cup (DMC) and standard mobility cup (SMC) in all rTHAs performed at our institution over a decade with a 1 year minimum follow-up.Methods: Two hundred ninety-five rTHAs (acetabular only and bipolar revisions) between 2006 and 2016 were retrospectively reviewed. These were divided into those with a DMC (184 revisions) or SMC (111 revisions). Dislocation and complications requiring re-revision were reported.Results: The rTHA mean age was 69 years ± 13.9 (19-92) and the mean follow-up was 2.3 years. Dislocation risk was statistically lower (P = .01) with a DMC (3.8%; 7/184) than with an SMC (13.5%; 15/111). DMC required re-rTHA in 24/184 (13%) for any reason compared to SMC in 19/111 (17.1%) (P = .34). There was no significant difference in early aseptic loosening (P = .28) between the 2 groups. For young patients (≤55 years), results were similar with a lower dislocation rate in the DMC group (P = .24) and no increased risk of early aseptic loosening (P = .49).Conclusion: This study demonstrates that for all rTHA indications DMC compared to SMC has a significantly decreased risk of postoperative dislocation without risk of early aseptic loosening at medium term follow-up. The use of DMC in rTHA is an important consideration particularly with the predicted increased incidence of both primary and revision THA globally. [ABSTRACT FROM AUTHOR]

The purpose of this retrospective study is to compare the short-term clinical and radiological results between standard and dual mobility THA for femoral neck fractures (FNF) in older patients. The hypothesis is that the dual mobility cup (DMC) has the same outcomes but a lower dislocation rate than the standard THA. The study population included 56 patients (mean age 77.7 years, range 71–85) that underwent THA for displaced FNF. Patients were divided in two comparable groups for baseline characteristics (age, sex and comorbidities): 28 patients underwent THA with a standard cup (SC) and 28 THA with DMCs. The clinical records and radiograms were reviewed to search relevant data in their postoperative history. Two postoperative dislocations occurred in the SC group and none in the DMC group. At an average follow up of 23 months (12–40), 48 patients were available for the final evaluation. The WOMAC score for all patients averaged 6.26 (0–46) and was slightly better in the DMC group (4.94 vs. 7.58; p-value = 0.41); scores were significantly better in presence of neurological comorbidities (p-value = 0.04), in the absence of diabetes (p-value = 0.04) and in the case of psychiatric disorders (p-value = 0.02). Radiographic evaluation at one year showed signs of osteointegration in 42/48 (87.5%) acetabular components (20 DMCs, 22 SC). According to our experience, DMCs proved to be a valid option for the treatment of displaced FNF in older patients, since it allowed them to achieve short-term outcomes comparable to conventional THA, while decreasing the incidence of postoperative dislocations.

Background: Dual mobility implants are subject to a specific implant-related complication, intraprosthetic dislocation (IPD), in which the polyethylene liner dissociates from the femoral head. For older generation designs, IPD was attributable to late polyethylene wear and subsequent failure of the head capture mechanism. However, early IPDs have been reportedly affecting contemporary designs. Methods: A systematic review of the literature according to the preferred reporting items for systematic reviews and meta-analyses guidelines was performed. A comprehensive search of PubMed, MEDLINE, Embase, and Google Scholar was conducted for English articles between January 1974 and August 2016 using various combinations of the keywords “intraprosthetic dislocation,” “dual mobility,” “dual-mobility,” “tripolar,” “double mobility,” “double-mobility,” “hip,” “cup,” “socket,” and “dislocation.” Results: In all, 16 articles met our inclusion criteria. Fourteen were case reports and 2 were retrospective case series. These included a total of 19 total hip arthroplasties, which were divided into 2 groups: studies dealing with early IPD after attempted closed reduction and those dealing with early IPD with no history of previous attempted closed reduction. Early IPD was reported in 15 patients after a mean follow-up of 3.2 months (2.9 SD) in the first group and in 4 patients after a mean follow-up of 15.1 months (9.9 SD) in the second group. Conclusions: Based on the current data, most cases have been preceded by an attempted closed reduction in the setting of outer, large articulation dislocation, perhaps indicating an iatrogenic etiology for early IPD. Recognition of this possible failure mode is essential to its prevention and treatment.

Since its creation in 1974, the Dual Mobility Cup (DMC) has been gaining in popularity, especially in the past decade. This intensive use could lead to inappropriate use and consequently to an increased complication rate. Compliance with conceptual requirements and surgical techniques will prevent the occurrence of complications that can be wrongly attributed to implants. In this context, we feel that it is essential to share our tips and tricks as well as an overview and an explanation of common errors, based on more than 45 years of clinical and research experience. From basic principles, including indications, implant choice and implant compatibility, to surgical tips, in this article orthopedic surgeons will find a practical overview of DMC in order to use it safely and with confidence.

Concept born from the observation that 1) systematic conventional techniques for implanting hip components are still affected by some complications that technological improvements have not entirely solved, and 2) the increasing awareness that abnormal lumbo-pelvic kinematics are responsible for clinically detrimental poor functional cup orientation and components' interaction (edge loading and articular impingement) that occur during activities of daily living. Following on from this, the kinematic alignment (KA) technique for total hip replacement (THR) has been developed and consists of personalising the implantation of components, with the intention of restoring the pre-arthritic hip joint anatomy: centre of rotation, acetabular anteversion, and proximal femur anatomy. The acetabular component orientation will be adjusted from its native orientation (transverse acetabular ligament) for patients with poor functional acetabular orientation due to an abnormal spine-hip relationship (≍10 to 35% of patients). As the majority of conditions that lead to hip degeneration are automatically corrected when anatomically replacing a hip, there is little-to-no risk of reproducing the hip anatomy, with the exception of developmental disease. The cup adjustment aims, by reaching a compromise, to optimise the components' interaction between the standing and the sitting positions. The intended benefits of the KA technique for THR are primarily to reduce risk of prosthetic instability and failure as a result of the improved functional components' interaction, and secondarily to improve functional performances and patient satisfaction due to the anatomical implantation and subsequent physiological prosthetic hip kinematics. A parallel may be drawn between the KA technique for THR and the concept of "restricted KA technique for total knee replacement", as in both techniques component positioning primarily aims to reproduce the native joint anatomy, with only a fraction of patients requiring component orientation adjustment in order to compensate for a biomechanically sub-optimal pre-operative joint condition. Planning a KA-THR is simple (physical examination and radiographic measurements to distinguish between hip and spine users, in order to define the individual spine-hip relationship), and surgery can be reliably performed free hand. As the pre-operative individual spine-hip relationship is also influenced by the stiff osteoarthritic hip (hip-spine syndrome), further research is needed to refine the indication and the level of cup orientation adjustment. [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]

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]

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]