CLINICAL RESEARCH

Dual Mobility Cup in Patients Younger Than 70 Years: Preliminary Results of a Case Series

María Florencia Molina, Guillermo A. Ricciardi, José D. Mancilla Vargas, Florencia S. Scaglione, Martín Loayza Gómez, Martín A. Pérez

Hip and Knee Disease Department, Orthopedics and Traumatology Service, Hospital General de Agudos “Teodoro Álvarez”, Autonomous City of Buenos Aires, Argentina

ABSTRACT

Objective: To evaluate the clinical and radiographic outcomes of patients younger than 70 years who underwent total hip arthroplasty with a dual mobility acetabular cup system. Materials and Methods: Retrospective descriptive study of 61 patients (mean age, 62 years) treated with cemented and uncemented dual mobility acetabular components between 2014 and 2019. Mean follow-up was 47 months (range, 36-86). Clinical evaluation included the Harris Hip Score and the Oxford Hip Score, together with radiographic assessment of both hips. Results: Indications for surgery were avascular necrosis of the hip (8 cases), femoral neck fracture (17 cases), and hip osteoarthritis (36 cases). During follow-up, no dislocations or component loosening were observed. One patient reported localized pain associated with trochanteric bursitis. The mean postoperative Harris Hip Score was 95 points, and the mean Oxford Hip Score was 45, which was a significant improvement. Conclusions: The dual mobility cup is a valid option for patients younger than 70 years, regardless of the underlying condition. Its use reduces the risk of prosthetic dislocation and provides good clinical outcomes, while also lowering hospitalization and reoperation costs.

Keywords: Dual mobility cup; primary total hip arthroplasty; adults under 70.

Level of Evidence: IV

Copa de doble movilidad: experiencia en pacientes <70 años. Resultados preliminares de una serie de casos

RESUMEN

Objetivo: Evaluar los resultados clínicos y radiográficos en una serie de pacientes <70 años sometidos a una artroplastia total de cadera con el sistema de copa acetabular de doble movilidad. Materiales y Métodos: Estudio descriptivo retrospectivo de 61 pacientes (edad promedio 62 años) tratados con un reemplazo de cadera utilizando componentes acetabulares cementados y no cementados con el sistema de doble movilidad, entre 2014 y 2019. El seguimiento promedio fue de 47 meses (rango 36-86). Para la evaluación se utilizaron el Harris Hip Score, el Oxford Hip Score y radiografías de ambas caderas. Resultados: Los cuadros operados fueron: 8 casos de necrosis avascular de cadera, 17 fracturas mediales de cadera y 36 coxartrosis. En el seguimiento, no se detectaron casos de luxaciones ni de aflojamiento de los componentes. Un solo paciente tuvo dolor localizado que se asoció a bursitis trocantérica. El Harris Hip Score funcional promedio fue de 95, mientras que el Oxford Hip Score fue de 45, lo que refleja mejorías posoperatorias significativas. Conclusiones: La copa de doble movilidad es una opción válida para pacientes <70 años, independientemente de su enfermedad de base. Su uso disminuye las luxaciones de la prótesis y obtiene buenos resultados clínicos, lo cual va acompañado de reducciones en los costos hospitalarios de internación, cirugías de reducción protésica y de revisión.

Palabras clave: Copa de doble movilidad; artroplastia total primaria; adultos menores de 70 años.

Nivel de Evidencia: IV

INTRODUCTION

The number of hip arthroplasties has increased over the years, in parallel with rising life expectancy. Likewise, an increase in complications has been recognized.¹ One of the most feared complications with Gibson’s posterolateral approach is dislocation of the prosthetic components. The dual-mobility system was developed in 1974 by the French surgeon Gilles Bousquet as a solution that, over time, has gained broad acceptance, displaced self-retaining cups, and, above all, improved biomechanical characteristics.² It is indicated in the presence of neurovascular injuries, neurological diseases, abductor (gluteus medius) deficiency, and in patients >70 years of age.¹

Total hip arthroplasty (THA) in patients <70 years implies that the implant materials will be exposed to daily activities of varying demands, as well as occupational and sports activities, over a long period of time, posing significant challenges related to osteolysis, wear, and stability.³

The objective of this study was to evaluate clinical and radiographic outcomes in a series of patients <70 years who underwent THA with a dual-mobility acetabular cup system.

MATERIALS AND METHODS

A descriptive, retrospective study was conducted, reporting preliminary results at 2 years of follow-up, in a series of patients treated with primary THA using a dual-mobility cup at a single center (a tertiary-care institution in the public health system of the Autonomous City of Buenos Aires) between January 2014 and December 2019 (Figures 1 and 2).

A sample was obtained according to the following inclusion criteria: age between 50 and 70 years, both sexes, having undergone THA with a dual-mobility cup (cemented, uncemented, or hybrid).

Exclusion criteria were: oncologic disease, arthritis/collagenopathies, severe cognitive impairment and bedridden status, follow-up <6 months, or noncompliance with postoperative instructions. Data were obtained from inpatient/outpatient medical records and the radiographic archive for the following study variables: pathologic diagnosis, functional scores, age, sex, comorbidities, and surgical risk.

All patients were operated using a Gibson posterolateral approach by the same surgical team. Domestically manufactured cups (Polygram®) and French-manufactured cups (SATURNE®) were used. All patients followed the same rehabilitation plan, consisting of sitting and isotonic/isometric exercises starting 24 hours after surgery. For cemented total prostheses, patients were instructed to stand with a 4-point walker and were discharged 48 hours after surgery; for uncemented and hybrid total prostheses, standing was indicated at 3 weeks, with discharge likewise at 48 hours. Finally, all patients were prescribed three weekly sessions of physical therapy, reinforced with daily home exercises. Sutures were removed at 18-21 days postoperatively in all cases. Function was assessed using the modified Harris Hip Score (HHS) and the Oxford Hip Score (OHS) before surgery and at 6, 12, and 24 months.⁴

The modified HHS, administered via patient questionnaire, evaluates post-hip-surgery outcome by considering pain and hip joint function. Specifically, the functional activities assessed are: gait (limp, support, distance tolerated), stair climbing, putting on socks and shoes, ability to sit, and use of public transport. The maximum score is 100. Scores of 90-100 are considered excellent; 80-89, good; 70-79, fair; and <70, poor. The OHS assesses quality of life in patients with hip osteoarthritis. It comprises 12 questions, each with five response options scored 0-4. The lowest total (0) indicates the most symptoms/difficulty; the highest (48) indicates no impact on quality of life. Quality-of-life categories: excellent >41, good 34-41, moderate 27-33, poor <27.

Radiographic outcomes were evaluated on anteroposterior and lateral projections to detect osteolysis, migration, and radiolucent lines, according to the regions described by DeLee and Charnley for the acetabulum and the Gruen zones for the femoral stem.^5,6

Sociodemographic variables (age, sex), fixation type (cemented, uncemented, hybrid), and underlying condition (trauma, osteonecrosis, osteoarthritis) were also recorded. This study complies with the guidelines of the Declaration of Helsinki regarding the use of identifiable information in human research. All patients provided consent to participate.

Statistical Analysis

Categorical variables are expressed as frequency and percentage, analyzed with the χ² test or Fisher’s exact test. Numerical variables are expressed as mean or median according to distribution, with corresponding dispersion measures (standard deviation and range). Student’s t-test was used to compare means for normally distributed variables between two groups, and ANOVA for comparisons across three or more groups. The Kruskal-Wallis and Friedman tests were used for nonparametric variables. A p value <0.05 was considered statistically significant. Analyses were performed using SPSS Statistics 25.

RESULTS

A total of 61 patients (30 women and 31 men) underwent THA with a dual-mobility acetabular cup system [cemented, n = 17 (27.9%); hybrid, n = 10 (16.4%); uncemented, n = 34 (55.7%)]. The mean age was 62.5 years. The following underlying conditions were recorded: hip osteoarthritis (36 cases, 59%), subcapital hip fracture (17 cases, 27.9%), and avascular necrosis of the hip (8 cases, 13.1%). Demographic characteristics are shown in Table 1.

For descriptive purposes, clinical and demographic characteristics were compared among disease groups; age distribution was the only statistically significant difference. Patients with avascular necrosis of the hip were younger (Figure 3). However, in the authors’ opinion, given that the sample comprised patients <70 years and considering the preliminary descriptive nature of the study, this difference is not clinically relevant to our investigation. Age, sex, body mass index, comorbidities, and ASA (American Society of Anesthesiologists) score are summarized in Table 2.

Over a preliminary 2-year follow-up, no serious surgery-related complications occurred (infection, prosthesis instability, loosening). One patient had localized pain associated with trochanteric bursitis; the overall complication rate was <2%.

Functional assessments with HHS and OHS reflected favorable early clinical progress, with statistically significant differences between preoperative scores and 2-year scores. Data are summarized in Table 3.

DISCUSSION

The survival rate was 100% at a mean follow-up of 47 months, comparable to the study by Gómez-García, which reported 97.6% at 31 months.⁷

The mean OHS for quality of life was 45, similar to results reported by Matsen et al., who found a mean OHS of 41.8 ± 6.28 at a mean 28.8-month follow-up.⁸

The mean HHS was 95, comparable to that reported by Puch et al. (95.6) at an average follow-up of 11 years.⁹ It should be emphasized that, in our study, the etiology prompting THA was heterogeneous, as scheduled primary replacements in patients with hip fractures due to bone fragility were included. This represents a study limitation due to potential selection bias in further analyses and precludes broad generalization of conclusions. Nonetheless, as a descriptive study intended to present outcomes in a series of patients <70 years, inclusion was accepted per the authors’ criteria.

It should also be clarified that, although all included patients were <70 years, there was a significant age difference in the fracture subgroup, with a higher mean age. In our setting, we have experience using dual-mobility cups as a valid option in patients >65 years, with acceptable functional outcomes and a relatively low dislocation rate (0.9%).¹⁰ According to registry data from Sweden and England, and reports by Bozic from the Mayo Clinic group, dislocation is the most common cause of revision within the first year.¹¹

CONCLUSIONS

Based on our results, primary THA with a dual-mobility cup in patients <70 years may represent a valid surgical option due to the low dislocation rate and good medium-term survival. However, these are preliminary findings that must be considered in the context of long-term follow-up. We believe it is essential to evaluate implant wear over time and to increase the number of cases, both representing limitations of the present study.

Further research is needed to compare the long-term outcomes of dual-mobility cups (with respect to wear) versus conventional cups. A strength of our study is that the proposed surgery resulted in no complications and enabled return to usual activities.

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11. Garabano G, Alonso MI, Pérez Alamino L, Jaime A, Cullari M, Pesciallo CÁ. Resultados iniciales del uso de cotilos de doble movilidad en pacientes <65 años con fractura de cadera. Análisis retrospectivo de 102 casos. Rev Asoc Arg Ortop Traumatol 2023;88(5):520-6. https://doi.org/10.15417/issn.1852-7434.2023.88.5.1757

G. A. Ricciardi ORCID ID: https://orcid.org/0000-0002-6959-9301

M. Loayza Gómez ORCID ID: https://orcid.org/0000-0001-9079-5641

J. D. Mancilla Vargas ORCID ID: https://orcid.org/0000-0002-0025-1251

M. A. Pérez ORCID ID: https://orcid.org/0000-0002-2163-0680

F. S. Scaglione ORCID ID: https://orcid.org/0000-0002-0261-380X

Received on January 27th, 2024. Accepted after evaluation on June 17th, 2025 • Dr. María Florencia Molina • florenciamolina1989@gmail.com • https://orcid.org/0000-0002-3747-044X

How to cite this article: Molina MF, Ricciardi GA, Mancilla Vargas JD, Scaglione FS, Loayza Gómez M, Pérez MA. Dual Mobility Cup in Patients Younger Than 70 Years: Preliminary Results of a Case Series. Rev Asoc Argent Ortop Traumatol 2025;90(5):410-416. https://doi.org/10.15417/issn.1852-7434.2025.90.5.1918

Article Info

Identification: https://doi.org/10.15417/issn.1852-7434.2025.90.5.1918

Published: October, 2025

Conflict of interests: The authors declare no conflicts of interest.

License: This article is under Attribution-NonCommertial-ShareAlike 4.0 International Creative Commons License (CC-BY-NC-SA 4.0).