Intraprosthetic Dislocation Following Dual Mobility Total Hip Arthroplasty: A Retrieval Analysis Study
Salar Sobhi1,2, Alan Kop3, Moreica Pabbruwe3
1Department of Orthopaedic Surgery, Fiona Stanley Fremantle Hospitals Group, Murdoch, Western Australia, Australia.
Arthroplasty Today
|January 15, 2025
Summary
Intraprosthetic dislocation (IPD) in dual mobility hip implants often follows failed closed reduction attempts after hip dislocation, indicating an iatrogenic cause. Further research is needed to identify other potential failure mechanisms in these complex cases.
Area of Science:
- Orthopedic surgery
- Biomaterials science
- Implant retrieval analysis
Background:
- Dual mobility (DM) implants are used in total hip arthroplasty to improve range of motion and reduce dislocation rates.
- Intraprosthetic dislocation (IPD), where the polyethylene (PE) liner disengages from the femoral head, is a known complication.
- Concerns regarding IPD in modern DM implants prompted this retrospective analysis due to limited existing literature.
Purpose of the Study:
- To investigate the incidence and failure mechanisms of intraprosthetic dislocation (IPD) in dual mobility (DM) implants.
- To analyze retrieved DM implants to understand the causes of IPD.
- To identify common failure modes for prevention and treatment strategies.
Main Methods:
- Retrospective analysis of 124 revised DM implants (110 primary, 14 revision) with a mean in situ time of 2.0 ± 3.1 years.
- Evaluation of demographics, clinical data, failure mechanisms, and revision observations.
- Retrieval analysis including assessment of metal and PE wear, corrosion, and bony ingrowth.
Main Results:
- Eleven cases of IPD were identified.
- Eight of the 11 IPD cases (73%) occurred after a failed closed reduction of a hip dislocation.
- The majority of IPD cases (82%) involved female patients; other failure mechanisms were not clearly defined for 3 cases.
Conclusions:
- IPD in DM implants frequently occurs iatrogenically after failed closed reduction of hip dislocations.
- No specific implant-related features were identified as definitive causes for all IPD cases.
- Understanding these failure modes is crucial for improving the management of IPD in DM total hip arthroplasty.
