Summary

Larger Exeter Stems have a higher rate of Late Peri-prosthetic fracture

Abstract

Introduction

Since 1970, the Exeter V40 cemented femoral stem has demonstrated excellent clinical and
radiographic outcomes as well as long-term survivorship for primary total hip arthroplasty.
However, recent studies have shown a trend of increased cumulative incidence for peri-prosthetic
femoral fractures (PPFF). This study aims to compare the large Exeter stems (Size 4-6) to
smaller Exeter stems (Size 0-3) to evaluate risk of revision for PPFF.

Methods

Data from AOANJRR were analysed for all primary total conventional hip procedures undertaken
for osteoarthritis using the Exeter stem for the period September 1999 to December 2021. The
primary outcome measures were the cumulative percent revision (CPR) for all causes and the
CPR for fracture. Results were adjusted for age and gender.

Results

94,884 primary THR procedures were undertaken for OA. Of these, 92,532 were Size 0-3 and
2,352 were Size 4-6. The CPR at 19 years was 8.3% (95% CI 7.7, 9.0) for the Size 0-3 group and
10.0% (95% CI 7.6, 13.1) for the Size 4-6 group. There was no difference in the overall risk of
revision when the two stem size groups were compared (entire period HR=1.19 (95% CI 0.97,
1.45), p=0.097). There was a higher CPR for PPFF for Size 4-6 stems compared to Size 0-3 from
3.5 years onwards (HR=2.27 (95% CI 1.47, 3.52), p<0.001).

Conclusion

The data shows an increased risk of revision for PPFF with larger stem sizes (Size 4-6) when
compared to smaller sizes (Size 0-3). PPFF was also identified as the most common cause for late-stage revision in larger sizes, after 10 years from the primary procedure.