Total hip arthroplasty reduces the risk of dislocation after femoral neck fracture.

INTRODUCTION

Femoral neck fracture in the elderly patient can either be managed using hemi-arthroplasty (HA) or total hip arthroplasty (THA). The aim of this study was to explore the rate of three selected complications in each procedure: is the dislocation rate higher with HA compared to THA? Is the blood transfusion rate higher with THA compared to HA? Do the patients who underwent THA require more ICU transfer than the patients who underwent HA? Is the ICU transfer correlated to the use of cement for stem fixation?

METHOD: Based on a national health-care database, a comparative and retrospective study was conducted. 96,184 patients were included after having a surgery for femoral neck fracture between 2014 and 2017. The mean follow up was 3.5 years (Min. 2 years-Max. 5 years). The population was divided into two groups: hemiarthroplasty (HA) and total hip arthroplasty (THA). The primary outcome was the dislocation rate and the secondary outcomes were the blood transfusion rate and the need for ICU after surgery.

RESULTS

At two years of follow up in the Hemiarthroplasty group, 3647 patients had a dislocation episode over 64,106 patients: 5.69%. In the Total Hip Arthroplasty group: 1904 patients had a dislocation episode over 32,078 patients: 5.94% (p=0.26711). The percentage of deceased patient without dislocation was 17.76% in the HA group and 11.56% in the THA group (p<0.001). The univariate hazard ratio for dislocation was higher in the THA group: HR 1.063 IC 95% (0.993-1.138) p=0.077. The multivariate analysis calculating competitive risk with death and dislocation found THA to be a protective factor of dislocation HR 0.926 IC 95% (0.866-0.991) p=0.0266. The rate of blood transfusion was 5.59% in the THA group and 7.03% in the HA group (p<0.001), The multivariate analysis found HR=1.062 IC 95% (0.99-1.139) p=0.0955. The need for ICU transfer after the surgery was 7.04% in the HA group and 8.08% in the THA group (p<0.001). The multivariate analysis found HR 0.995 IC 95% (0.921-1.076) p=0.9094. Finally, only cement was found as an independent risk factor of ICU transfer after surgery: HR 1.254 IC 95% (1.164-1.35) p<0.0001.

CONCLUSION

THA for femoral neck fracture allows to reduce the risk of dislocation compared to hemiarthroplasty. The multivariate analysis failed to prove the superiority of one procedure over the other regarding blood transfusion risk and the need for ICU transfer. The use of cemented stem appears to be a risk factor of ICU transfer after hip arthroplasty.

LEVEL OF EVIDENCE: III, Retrospective comparative study.