Dual Mobility Cups in Hip Fracture Patients (DUALITY)

Do Dual Mobility Cups Prevent Dislocation After Total Hip Arthroplasty Performed Due to Femoral Neck Fracture? A Registry-based, Pragmatic, Randomized Controlled Trial Comparing Dual Mobility With Standard Cups

Our aim is to develop a strategy that reduces the risk of dislocations after total hip arthroplasty surgery performed due to femoral neck fracture. We therefore perform a register-nested, pragmatic, randomized controlled trial to investigate the safety and efficacy of dual mobility cups that were designed to minimize the risk of dislocation in the large and fragile group of elderly patients with femoral neck fractures.

Study Overview

• Status: Completed
• Conditions: Femoral Neck Fractures
• Intervention / Treatment: Device: Dual mobility cup; Device: Standard cup

Detailed Description

Total hip arthroplasty (THA) is regularly performed in patients with a femoral neck fracture. However, dislocation is very common after THA in hip fracture patients, and this complication is deleterious to health and quality of life. The dual mobility cup offers a technical solution that potentially reduces the risk of dislocation. There is however no high-level evidence to support the general use of dual mobility cups in patients with displaced femoral neck fractures, and the purpose of the proposed study is to provide evidence to support or refute the use of this concept in the very large group of hip fracture patients.

We a register-nested, pragmatic randomized controlled trial (RCT) to investigate the safety and efficacy of dual mobility cups that were designed to minimize the risk of dislocation after THA. Our aim is thus to investigate whether the incidence of dislocations after THA surgery performed due to femoral neck fracture can be reduced by the use of this device.

The intervention group receives a dual mobility cup (of any brand that is in general use in Sweden), and the control group receives a standard cup (of any brand that is in general use in Sweden). The choice of cup or stem fixation (cemented or uncemented), femoral head size, brand of stem type, surgical approach, antibiotic prophylaxis, and postoperative mobilization are up to the surgeon's choice and the routines that are relevant at each study site.

The necessary infrastructure for this register-nested RCT is present within the Swedish Hip Arthroplasty Register (SHAR) and the Swedish Fracture Register (SFR). Pre-operative registration of fractures is already established within the SFR, and an online platform to screen, include and randomize eligible patients is established. Cross-matching of data from the SFR and the SHAR with the database of the Swedish Patient Register (SPR) is performed in order to catch endpoint not routinely collected by the SHAR.

Expanded recruitment in collaboration with UK, WHITE 12-Duality, started 10/09/2022. https://www.isrctn.com/ISRCTN11895196

• Study Type: Interventional
• Enrollment (Actual): 1600
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Uppsala, Sweden, 75185
    • Nils Hailer
• United Kingdom
  • London, United Kingdom
    • Queen Mary University of London

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 61 years and older (Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Written informed consent
• Diagnosis: displaced femoral neck fracture type AO 31-B2 or B3/Garden type 3 or 4
• Eligible for THA according to local guidelines and routines

Exclusion Criteria:

• Previous inclusion of contralateral hip
• Delayed fracture surgery (date of injury >7 days prior to date of randomization)
• Pathological or stress fracture of the femoral neck, or fracture adjacent to a previous ipsilateral hip implant
• Inability or unwillingness to give written consent
• Dementia (as diagnosed by the screening physician)
• Unavailability of both interventions for a study subject (e.g., implants being out of stock, or lack of the individual surgeon's expertise to perform either procedure)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention; Insertion of dual mobility cup	Device: Dual mobility cup; Patients with a displaced femoral neck fracture eligible for THA receive a dual mobility cup, as opposed to a standard cup in the control group.
Active Comparator: Control; Insertion of standard cup	Device: Standard cup; Patients with a displaced femoral neck fracture eligible for THA receive a standard cup, as opposed to a dual mobility cup in the experimental group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dislocation	Dislocation will be ascertained by identifying the occurrence of any closed or open reduction of the previously inserted THA (the "index joint") within one year after surgery.	1 year after index surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Any re-operation of the index THA	Re-operation will be defined as the occurrence of any surgical procedure performed on the previously treated hip within one year after surgery.	1 year after index surgery
Periprosthetic joint infection	Periprosthetic joint infection will be defined as the occurrence of any sign of deep infection around the previously inserted THA within one year after surgery, defined by registration of ICD or NOMESCO codes.	1 year after index surgery
Patient-reported outcome	Patient-reported outcome as assessed by EQ-5D-VAS (routinely collected by the SFR at index surgery in order to obtain pre-trauma baseline, and 1 year post-operatively)	1 year after index surgery
Short-term mortality	90-day mortality, as registered in the NPR	90 days after index surgery
Medium-term mortality	365-day mortality, as registered in the NPR	365 days after index surgery
Cost-effectiveness	Procedural costs for intervention and control treatment will be recorded at all sites, ensuring documentation of baseline costs for the two treatment alternatives. Procedural costs of admissions for closed reductions as well as for reoperations will also be collected from all units.	1 year after index surgery

Collaborators and Investigators

• Sponsor: Uppsala University
• Collaborators: The Swedish Research Council
• Investigators: Study Chair: Stergios Lazarinis, MD, PhD, Uppsala University Hospital

Publications and helpful links

General Publications

• Wolf O, Mukka S, Notini M, Moller M, Hailer NP; DUALITY GROUP. Study protocol: The DUALITY trial-a register-based, randomized controlled trial to investigate dual mobility cups in hip fracture patients. Acta Orthop. 2020 Oct;91(5):506-513. doi: 10.1080/17453674.2020.1780059. Epub 2020 Jun 22.

Study record dates

Study Major Dates

• Study Start (Actual): January 17, 2020
• Primary Completion (Actual): September 24, 2025
• Study Completion (Actual): September 24, 2025

Study Registration Dates

• First Submitted: April 8, 2019
• First Submitted That Met QC Criteria: April 8, 2019
• First Posted (Actual): April 10, 2019

Study Record Updates

• Last Update Posted (Estimated): October 3, 2025
• Last Update Submitted That Met QC Criteria: September 29, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: total hip arthroplasty; mortality; periprosthetic joint infection; dual mobility cup; dislocation; health economy
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Wounds and Injuries; Joint Diseases; Leg Injuries; Fractures, Bone; Femoral Fractures; Hip Injuries; Hip Fractures; Joint Dislocations; Femoral Neck Fractures
• Other Study ID Numbers: 2018-101; ISRCTN11895196 (Registry Identifier: The UK's Clinical Study Registry)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes