Extended trochanteric osteotomy (ETO) and fluted tapered modular stems in revision hip arthroplasty. Does ETO integrity or consolidation, really matter?

INTRODUCTION

The objective of this study was to assess if the fracture and/or non-union of extended trochanteric osteotomy (ETO) affected the behavior and survival of modular fluted and tapered distal fixation stems in revision total hip arthroplasties (rTHA).

METHODS

We retrospectively analyzed 52 rTHA in 52 patients. Preoperative diagnoses were mechanical loosening (42 cases), septic loosening (8), periprosthetic fracture (1), and femoral stem fracture (1). According to the Paprosky classification, femoral bone stock deficiencies were 19 type-II, 26 type IIIA, and 7 type IIIB. We assessed the behavior of the osteotomy (union, fracture, migration) and the survival and behavior (integration and subsidence) of prosthetic femoral stems.

RESULTS

ETO union and non-union rates were 84.61% (44 patients) and 15.38% (8 cases) respectively. There were twelve (23%) intra-operative fractures of the osteotomy fragment and 11 (21.15%) migrations (4.5 mm on average). We observed bone union in 39 (75%) stems and 13 (25%) stable fibrous unions. Nine (17.3%) stems subsided 7 mm (2-15 mm) on average before becoming stable. Stem subsidence and integration was not significantly affected by ETO fracture/no fracture or union/non-union. The postoperative Harris Hip Score (HHS) improved significantly as compared to the pre-operative HHS (38.41 ± 3.54 vs 85.29 ± 3.36; p < 0.01). Patients were followed up for 55 (24-100) months. The overall implant survival at the end of follow-up was 100%.

CONCLUSIONS

In this series, neither the non-union nor the intra-operative fracture of the ETO segment affected the behavior or medium-term survival of femoral stems.