BACKGROUND: 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).
CONCLUSIONS: 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.

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.
OBJECTIVE: 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.
CONCLUSIONS: 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.
METHODS: IV; cadaveric study.

UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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).
UNASSIGNED: 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.

OBJECTIVE: 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.
CONCLUSIONS: 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.

BACKGROUND: 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°).
CONCLUSIONS: 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.

UNASSIGNED: Total hip arthroplasty (THA) is a common procedure used to treat various hip conditions. However, patients with ochronotic arthropathy, a rare genetic disorder characterized by the abnormal accumulation of homogentisic acid, are at a higher risk of post-surgical dislocation and instability due to poor bone quality and joint degeneration.
UNASSIGNED: This case study features a 52-year-old male patient diagnosed with ochronotic arthropathy who underwent bilateral THA with the use of a dual mobility cup (DMC). Ochronotic arthropathy had caused significant joint degeneration and stiffness, leading to considerable functional impairment.
UNASSIGNED: The application of a DMC in THA for patients with ochronotic arthropathy has shown promising outcomes. The DMC offers increased range of motion and improved stability, effectively reducing the risk of post-surgical dislocation and implant failure. This case study highlights the potential of DMC as a viable solution for addressing the challenges posed by poor bone quality in patients with ochronotic arthropathy undergoing THA.

UNASSIGNED: Dislocation rate of total hip arthroplasty (THA) can be as high as 20% for patients with fracture neck of femur, which is a disastrous complication in these vulnerable patients. Numerous techniques, including bipolar arthroplasty and constrained liner, have been adopted to minimize the risk of dislocation. We aimed to evaluate the role of dual mobility Cups in treating patients with fractures of the femoral neck with high risk of postoperative dislocation due to neuromuscular instability disorders.
UNASSIGNED: A prospective cohort study was conducted (place is blinded as asked during submission), between 2016 and 2019, with a post-operative follow up period of two years. We included skeletally mature patients with femoral neck fractures having neuromuscular disorders and cognitive dysfunction who are candidates for THA above 60 years. Patients were then followed up clinically and radiographically at the clinic using Harris Hip Score (HHS) and x-rays at six weeks, six months, one year and two years postoperatively.
UNASSIGNED: Twenty patients (20 hips) with femoral neck fractures with high risk of postoperative dislocation due to neuromuscular instability disorders undergoing dual mobility cup were included. The mean age of patients was 70.5 ±6.42 years. There is highly significant difference between HHS preoperatively and postoperatively (six weeks, six months and one, two years) p<0.001.Infection occurred in one case (5 %), sciatic nerve injury occurred in one case (5%), and none of the patients had postoperative dislocation.
UNASSIGNED: Dual mobility cup is effective in preventing early dislocation in patients suffered from fracture neck of femur with muscle weakness due to neurologic disorders.

BACKGROUND: 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).
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
METHODS: Level III.

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.

BACKGROUND: 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 < 0.0001). There were no postoperative dislocations recorded, nor any iliopsoas-impingement or symptomatic cam-effect.
CONCLUSIONS: This study showed excellent survival and good radiological and clinical results of this dual mobility cup at a mid-term follow-up. None of the patients had dislocation or any specific complication feared with dual mobility cups.