Dual mobility cup reduces dislocation and re-operation when used to treat displaced femoral neck fractures.
OBJECTIVE
Total hip arthroplasty (THA) as primary treatment for displaced femoral neck fractures is controversial as THA is associated with higher rates of dislocation but lower rates of re-operation compared to hemiarthroplasty (HA). A dual mobility cup (DMC) design is associated with lower dislocation and re-operation rates in elective surgery. Is this also the case when used to treat displaced femoral neck fractures? The aim of this study is to compare rates of dislocation and re-operation of any kind following treatment for displaced femoral neck fractures with either bipolar HA or THA with DMC.


METHODS
Two consecutive groups of patients treated for displaced femoral neck fractures at the Regional Hospital in Viborg in Denmark were included. In 2007-2008 171 patients (mean age 84.1 years) were treated with bipolar HA. In 2009-2010 175 patients (mean age 75.2 years) were treated with THA with DMC. Data regarding rates of dislocation and re-operation were obtained by retrospective review of medical records.


RESULTS
We found a statistically significant difference regarding rates of dislocation and re-operation of any kind in favour of THA with DMC. Dislocation occurred in 25/171 patients [95 % confidence interval (CI) 9.3-19.9 %] treated with bipolar HA and 8/175 patients (95 % CI 1.5-7.7 %) treated with THA with DMC (p = 0.002). Re-operations were required in 32/171 patients (95 % CI 12.9-24.6 %) treated with bipolar HA and 16/175 patients (95 % CI 4.8-13.4 %) treated with THA with DMC (p = 0.01).


CONCLUSIONS
Our findings indicate that THA with DMC is superior to bipolar HA following treatment for displaced femoral neck fractures in regard to rates of dislocation and re-operation.
Department of Orthopaedic Surgery, The Regional Hospital in Viborg, Heibergs Allé 4, 8800, Viborg, Denmark, asbensen@yahoo.dk.
Anne S
AS
Bensen
Thomas
T
Jakobsen
Niels
N
Krarup
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D005260:Female; D005265:Femoral Neck Fractures / Q000601:surgery*; D062785:Hemiarthroplasty / Q000009:adverse effects; D006617:Hip Dislocation / Q000209:etiology / Q000517:prevention & control; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies