[Dislocated dual mobility liner after hip dislocation].

Intraprosthetic dislocation (IPD) during closed reduction in primary total hip arthroplasty (THA) with a dual mobility cup (DMC) is a well-known, but rare complication. DMC accounted for 15% of all cups in primary THA in Denmark in 2018, and the prevalence of DMC is increasing. We present a case report of an 83-year-old man, who had an atraumatic hip dislocation five weeks after primary THR. After closed reduction with sedation in the emergency department, IPD occurred. We recommend repositioning of a dislocated THA with DMC to be done by use of fluoroscopy under general anesthaesia with muscle relaxation.

No dislocations after primary hip arthroplasty with the dual mobility cup in displaced femoral neck fracture in patients with dementia. A one-year follow-up in 20 patients.

PURPOSE: The aim of this study was to describe the dislocation rates, reoperation rates and mortality 30 day and one year following THA with AVANTAGE® dual mobility cup among dementia patients with an acute displaced intracapsular femoral neck fracture. PATIENTS AND METHODS: From 2010 to 2014 we identified 20 hip fracture patients with dementia, who have had total hip arthroplasty with the AVANTAGE® dual mobility cup. The primary outcome was dislocation. Secondary outcomes were revision surgery, 30 days and one year mortality, time to surgery and length of hospital stay. RESULTS: Follow-up time was one year. None of the patients experienced dislocation or received revision surgery in the follow-up period. The 30-days mortality rate was 25% (confidence interval (CI) 95%; 4-46%) and the one year mortality was 45% (CI 95%; 21-69). Mean time to surgery was 27 h (CI 95%; 20-37 h) and mean length of hospital stay was 5.5 days (CI 95%; 4, 0-7, 6 days). CONCLUSION: THA with the dual-mobility cup seems favourable in the treatment of patients with a displaced femoral neck fracture and patients with dementia. Correct placement of the cup is pivotal and technically demanding. Not all orthopedic surgeons perform total hip arthroplasty while challenges regarding the logistics can be encountered since time to surgery is known to affect the mortality negatively.