Joint motion of bipolar hemiarthroplasty in routine hip functional movements: a dynamic motion study

Revision rate following unipolar versus bipolar hemiarthroplasty

INTRODUCTION

There has been much debate on use of bipolar or unipolar femoral heads in hemiarthroplasty for the treatment of femoral neck fractures. The outcome of these implants should be studied in the America Joint Replacement Registry (AJRR).

METHODS

All primary femoral neck fractures treated with hemiarthroplasty between January 2012 and June 2020 were searched in the AJRR. All cause-revision of unipolar and bipolar hemiarthroplasty and reasons for revision were assessed for these patients until June of 2023.

RESULTS

There were no differences in number and reason for all cause revisions between unipolar and bipolar hemiarthroplasty (p = 0.41). Bipolar hemiarthroplasty had more revisons at 6 months postoperatively (p = 0.0281), but unipolar hemiarthroplasty had more revisions between 2 and 3 years (p = 0.0003), and after 3-years (p = 0.0085), as analysed with a Cox model. Patients with older age (HR = 0.999; 95% CI, 0.998-0.999; p = 0.0006) and higher Charlson Comorbidity Index (HR = 0.996; 95% CI, 0.992- 0.999; p = 0.0192) had a significant increase in revision risk.

CONCLUSIONS

We suggest that surgeons should consider using bipolar prosthesis when performing hemiarthroplasty for femoral neck fracture in patients expected to live >2 years post injury.

Patients with femoral neck fractures treated by bipolar hemiarthroplasty have superior to unipolar hip function and lower erosion rates and pain: a systematic review and meta-analysis of randomized controlled studies

PURPOSE

We assessed acetabular erosion, hip function, quality of life (QoL), pain, deep infection, mortality, re-operation and dislocation rates in patients with displaced femoral neck fractures (dFNFs) treated with unipolar versus bipolar hemiarthroplasty at different postoperative time points.

METHODS

Relevant Randomized Controlled Trials (RCTs) were identified, following comprehensive literature research in Medline, Cochrane Central and Scopus databases, from conception until August 31th, 2021 and analyzed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Database research retrieved 120 studies; sixteen met eligibility criteria, providing 1813 (1814 hips) evaluable patients. Acetabular erosion was significantly higher for unipolar group at 6 and 12 months (p = 0.02 and p = 0.01 respectively). Patients in the bipolar group presented significantly better hip function at 12 and 24 months (p = 0.02 and p = 0.04 respectively). Postoperative pain was significantly less in the bipolar group at 12, 24 and 48 months (p = 0.01). No statistically significant differences were found regarding the postoperative rates of deep infection, mortality, re-operation and dislocation.

CONCLUSION

This study showed that patients with dFNFs treated with bipolar hemiarthroplasty have lower acetabular erosion rates at 6 and 12 months postoperatively, better hip function at 12 and 24 months, better QoL and less pain, when compared with unipolar. No statistically significant difference could be established regarding deep infection, mortality, re-operation and dislocation rates.