Total hip arthroplasty (THA) is the gold standard of care for all end-stage hip joint pathology. This includes osteoarthritis, avascular necrosis, hip destructive syndrome, and severe comminuted femoral neck and head fractures. However, complications may arise and necessitate revision surgery. Generally, due to mechanical forces exceeding the stability provided by the implant’s design, hip dislocations occur contributing to early surgical failure¹⁾. The leading cause of subsequent early revision procedures is postoperative instability¹⁾. Dual mobility (DM) cups were introduced in France 40 years ago, to address postoperative hip dislocation, and have significantly evolved in both design and fixation^2,3). Enhanced stability provided by DM cups (DMCs) is attributed to a dual articulation mechanism that allows increased jump distance, and range of motion prior to impingement and subsequent impingement. Recent advances in the literature emphasize, in short to mid-term follow-up evaluation, low dislocation rates with robust survival rates^4-7). Indications for DM application have progressively expanded beyond revision THA procedures to primary THA^2,8). Appropriate demographics for DMC application are represented in primary THA for patients with pelvitrochanteric insufficiency, diminished spinopelvic mobility, neuromuscular disorders, obesity, and femoral neck fractures^2,8-12). Long-term survivability, particularly in primary THA, have yet to be fully elucidated, highlighting the dynamic and evolving nature of this field²⁾.

This manuscript aims to analyze DM trends within arthroplasty literature published between 1982-2022. Contributing journals, authors, countries, and articles are identified. Trending keywords and themes are further explored to highlight evolving DM THA trends.

The Web of Science (WoS) Core Collection, courtesy of Clarivate Analytics, was selected for data availability and its extensive utilization in bibliometric studies. A literature review was conducted using both the Science Citation Index Expanded (SCIE) and the Social Science Citation Index (SSCI). The search strategy included the terms: “hip” (Topic) AND “arthroplasty” OR “replacement” (Topic) AND “dual mobility” OR “triple mobility” OR “double mobility” (All Fields) AND “1982-2022” (Year Published) AND “article” (Document Type). To reduce the risk of overlooking relevant studies, this study selected articles as the document type and employed the SCIE and SSCI indices, covering the time frame from 1982 to 2022. Search terms regarding DM THA were chosen based on an examination of published literature of frequently used keywords.

Two authors conducted data collection and screening to gather relevant data necessary for further analysis. Pertinent details included year of publication, title, authors, affiliated institutions, countries of origin, publishing journal, abstracts, references, citations, and the impact factor.

Bibliometric data were extracted from the WoS database and then imported into Excel format for advanced analysis. Data discrepancies were verified against the WoS database.

Data, sourced from different regions of interest, were classified based on their respective countries. VOSviewer (ver. 1.6.19.0; Leiden University) and Bibliometrix (University of Naples Federico II) were used to generate visualization techniques, which included knowledge maps depicting scientific output, co-authorship and co-citation networks, topics trend, thematic maps, dual-map overlays, and thematic evolution.

1. Research Output and Geographic Contributions

A WoS database search revealed 314 articles related to DM in hip arthroplasty from 1982 to 2022. Across these databases, the average citation count was 19.96 citations per document. Global annual publication volumes with a notable upward trend and annual growth rate of 16.97% are shown in Fig. 1. In 2017, the biggest annual upsurge in publication volume occurred with 18 papers published that year. This was followed by the 5 papers published each year in 2012, 2014, and 2016.

Figure 1. Trends in annual research output on dual mobility total hip arthroplasty (1998-2022).

Global research output, with the data primarily sourced from US-based registries. Publications originated from 35 different countries. France and the US were the predominant contributors with 266 and 202 articles, respectively. The top 10 contributing countries included six from Europe, two from Asia/Oceania, and two from North America. Other notable contributors were the UK (57 articles), Australia (52 articles), Sweden (44 articles), Denmark (26 articles), and Switzerland (26 articles). The countries with the highest citation numbers were France with 3,433 citations, the USA with 1,430 citations, and Sweden with 304 citations (Fig. 2).

Figure 2. Comparative analysis of research output by country over time.

Forty-five different institutions published at least one paper on DM in THA. The top five leading institutions were Udice-French Research Universities with the highest contribution of 35 articles, followed by Hospital for Special Surgery (25), Université Claude Bernard Lyon (20), Centre Hospitalier Universitaire (CHU) Lyon (18), and CHU de Saint Etienne (16). Contributions were made to DM in THA research by 1,131 authors. This study analyzed authors with the greatest research output, with Frédéric Farizon leading with 22 publications, followed by Rémi Philippot from CHU de Saint Etienne (17), and Bryan Boyer from Franciscan Health (16). The most cited authors were also analyzed, with Frédéric Farizon receiving 509 citations, followed by Rémi Philippot and Bryan Boyer, with 285 citations each. Impact factor by h-index was examined as well, with Frédéric Farizon leading with a score of 15, followed by Rémi Philippot with 12 and Bryan Boyer with 11.

2. Leading Journals and Key Studies

Sixty-two journals published studies specifically on DM THA between 1995 and 2022. Journal productivity is illustrated in Fig. 3. The Journal of Arthroplasty had the greatest number with 62 articles published. International Orthopaedics and Orthopaedics & Traumatology: Surgery & Research followed with 50 articles and 27 articles, respectively. In 2020, the Journal of Arthroplasty saw a peak in publication with 11 relevant articles. The Journal of Arthroplasty (1,620 citations), Clinical Orthopaedics and Related Research (1,420 citations), and International Orthopaedics (976 citations) were the top cited journals. The top five journals with the greatest impact by h-index are the Journal of Arthroplasty with an h-index of 22, International Orthopaedics with an h-index of 21, Orthopaedics & Traumatology: Surgery & Research with an h-index of 15, Clinical Orthopaedics and Related Research with an h-index of 14, and Bone & Joint Journal with an h-index of 9.

Figure 3. Trend of scholarly output by journal over time.

Works by Philippot et al.¹³⁾ (2009) with 146 citations, Boyer et al.¹⁴⁾ (2012) with 138 citations, and Langlais et al.⁴⁾ (2008) with 134 citations were included in the most influential articles.

3. Emerging Research Themes

A tree-map visualization depicting keyword trends in DMCs is displayed in Fig. 4. Out of a 455 keywords total, 44 keywords appeared with a minimum frequency of 15 times. Thirty-six displayed sufficient link strength to form occurrence clusters. A co-occurrence visualization with size correlating to the frequency of occurrence is demonstrated in Fig. 4A. Fig. 4B illustrates, with corresponding time periods, the visualization of these clusters.

Figure 4. (A) Network visualization of keyword co-occurrence with cluster identification for a minimum occurrence of 15. (B) Temporal keyword co-occurrence map highlighting thematic evolution over time.

A bibliometric analysis was performed in this study to pinpoint the trending themes in DM THA studies. In the existing literature, relevant countries, influential journals, authors, institutions, articles, collaboration, and keywords were identified to highlight hotspots.

1. Analysis of Publication and Leading Contributors

Global scientific output demonstrates an ascending annual production trajectory of scholarly articles, with an annual growth rate of 16.97%. This immense rate of growth reflects the relevance of this research area and the growing interest it attracts.

France was the most prolific country with the highest number of published articles, yearly productivity, and aggregate citations among the various countries analyzed. An explanation may be because DM was initially introduced in France^2,3). The top international collaboration was France/Switzerland with 6 joint publications, followed by France/USA with 6, the USA/United Kingdom with 5, and France/Lebanon with 4.

As recognition of these articles is crucial for understanding current trends and future hotspot detection, the top articles with the greatest impact in DM THA were identified. DM THA is effectively demonstrated by these collective studies to prevent dislocations, highlight long-term stability, and show low loosening rates in THA revisions, especially in high-risk patients^4,13,14).

2. Thematic Analysis

In Fig. 4, the co-occurrence overlay visuals demonstrate keyword clusters and associated themes throughout different time periods. Seven thematic clusters were identified including: Mechanical Complications Analysis and Assessment, Comparison of Outcomes with Alternative Components, and the Study of Metallosis and Corrosion.

1) Mechanical Complications Analysis and Assessment

The Mechanical Complications Analysis and Assessment cluster included the following keywords: acetabular component, adverse-reaction, dislocation, impingement, instability, intra-prosthetic dislocation (IPD), motion, osteolysis, outcomes, pseudotumor, revision, risk factors, survival, wear, socket, and stability. This cluster is particularly focused on the associations of biomechanical challenges and potential complications with DM THA.

DM technology has been introduced to mitigate the recognized risks of adverse reactions and dislocation complications in THA¹⁾. To reduce the risk of dislocation, the unique dual articulation of DM components is designed to provide greater range of motion while maintaining stability¹⁵⁾. During normal range of motion, the primary articulation between the prosthetic femoral head and the mobile polyethylene liner is engaged^16,17). Prior to dislocation, the secondary articulation between the liner and acetabular cup is engaged when motion exceed the normal range of motion, thereby accommodating for extreme positions^16,17). Decreasing the risk of dislocation, DM designs enable a superior head-to-neck ratio, a larger jump distance, and a minimum distance of femoral head travel prior to dislocation from the acetabular cup^16,18). However, the DM system complexities introduce mechanical concerns such as IPD and wear. Unique to DM THA, IPD occurs when the mobile polyethylene liner disengages from the femoral head. While IPD remains a specific concern associated with DMCs, it was observed to be uncommon, with an average occurrence rate of 0.6% across studies¹⁹⁾. Furthermore, design improvements, such as enhanced rim durability and advanced polyethylene materials, have further reduced the incidence of IPD, especially after closed reduction of dislocated DM THA, with newer-generation DM constructs²⁰⁾.

Conversely, impingement in THA is an abnormal mechanical interaction causing pain and limited motion between components and soft tissues²¹⁾. When compared to traditional THA designs, DMCs have an inherent extra-articulating surface providing greater freedom of motion with reduced impingement²²⁾.

Compared to conventional and constrained designs, DM constructs have been shown to exhibit lower resistive torque during subluxation events and reduced stress on the polyethylene and implant-bone interface¹⁷⁾. Despite these benefits, in the face of mechanical challenges, long-term studies are needed to confirm the efficacy and safety of DM components¹⁷⁾.

2) Comparison of Outcomes with Alternative Components

The comparative effectiveness of various THA components is presented in the Comparison of Outcomes with Alternative Components cluster. This cluster included the following keywords: articulation, constrained acetabular component, failure, implants, liners, polyethylene, tripolar implants, and recurrent dislocation.

Constrained acetabular liners (CAL) are designed to prevent dislocation by incorporating a locking mechanism to physically restrict the movement of the femoral head within the liner. Ongoing arthroplasty research has evaluated the efficacy and performance of various implants. A Van Eecke et al.¹⁹⁾ study demonstrated DMCs with superior performance when compared to CAL in revision THA. DMCs achieved a 94.7% survival rate, 2.6% dislocation rate, and 1.0% acetabular loosening rate, compared to CAL’s 81.0% survival rate, 11.0% dislocation rate, and 2.0% acetabular loosening rate in a study reviewing short- to mid-term outcomes¹⁹⁾. These results should be viewed within a broader research context even though DMCs have suggested advantages. Further studies in revision THA are recommended to form a comprehensive view of best practices¹⁹⁾.

3) Study of Metallosis and Corrosion

The Study of Metallosis and Corrosion cluster included keywords such as corrosion, metal ions levels, pseudotumor, and taper. In the setting of DM THA, there is a growing body of evidence in the literature exploring the pathology of metallosis and corrosion. Studies have highlighted the critical role of material selection in implant designs in risk mitigation. Notably, the outcomes of utilizing different materials for femoral head manufacturing in young, active patients was investigated by Nam et al.²³⁾. Their study employed prostheses that were comprised of a modular cobalt-chromium liner and a titanium acetabular shell and, based on the size of the acetabular component, options for either cobalt alloy or ceramic femoral heads²³⁾. Nam et al.²³⁾ also discovered that ceramic heads were linked to lower levels of metal ions compared to cobalt alloy heads, suggesting that ceramics might reduce metallosis risk, thereby enhancing the safety and efficacy of hip replacements. Furthermore, Kamath et al.²⁴⁾ proved that elevated serum levels of specific metal ions, such as cobalt and chromium, can arise from fretting corrosion at the interface where the cobalt-chromium liner meets the titanium acetabular component, leading to pseudotumor development. These pseudotumors are serious complications characterized by granulomatous masses that can cause pain, implant loosening and, ultimately, mechanical failure of the joint replacement²⁴⁾. Thus, to effectively manage this risk, Civinini et al.²⁵⁾ have emphasized the importance of vigilant monitoring of serum metal ion levels in patients with modular DM components.

Moreover, a significant issue in modular orthopedic implants, to effectively manage this risk, specifically affects the interface between the femoral stem and head. This type of corrosion releases metal ions into surrounding tissues and the bloodstream and is facilitated by mechanical micromotion and electrochemical reactions among differing metals in the implant exposed to body fluids. This type of corrosion can be exacerbated by designs that incorporate mismatched metals, such as titanium and cobalt-chromium. Matsen et al.²⁶⁾ noted that certain constructs could elevate metal ion levels, and potentially increase the risk of taper corrosion. This underscores the critical need for careful consideration of implant materials and continuous patient postoperative monitoring to mitigate systemic and local toxicological reactions induced by these released metal ions^26,27).

Conversely, a complex interplay of factors influencing metal ion postoperative levels was indicated when Barlow et al.²⁸⁾ examined metal ion levels across various bearing surfaces, including DM configurations, and found no significant differences.

This bibliometric analysis highlights the evolving landscape of DM THA research, with emphasis on current implant design trends. There has been a global increase in scholarly interest with the greatest contributions from France and the USA. In the field of DM THA, the Journal of Arthroplasty was the most relevant journal and Frédéric Farizon was the most relevant author. These elements emphasize the continuing and evolving research within DM components, highlighting the continued efforts to fill this area. This study identifies key trends and thematic evolution to guide future research.

No funding to declare.

No potential conflict of interest relevant to this article was reported.