Monoblock tapered stems in management of UCS B2 and B3 periprosthetic fractures in revision total hip arthroplasty

Abstract

Aims: United Classification System (UCS) B2 and B3 periprosthetic fractures in total hip arthroplasties (THAs) have been commonly managed with modular tapered stems. No study has evaluated the use of monoblock fluted tapered titanium stems for this indication. This study aimed to evaluate the effects of a monoblock stems on implant survivorship, postoperative outcomes, radiological outcomes, and osseointegration following treatment of THA UCS B2 and B3 periprosthetic fractures.

Methods: A retrospective review was conducted of all patients who underwent revision THA (rTHA) for periprosthetic UCS B2 and B3 periprosthetic fracture who received a single design monoblock fluted tapered titanium stem at two large, tertiary care, academic hospitals. A total of 72 patients met inclusion and exclusion criteria (68 UCS B2, and four UCS B3 fractures). Primary outcomes of interest were radiological stem subsidence (> 5 mm), radiological osseointegration, and fracture union. Sub-analysis was also done for 46 patients with minimum one-year follow-up.

Results: For the total cohort, stem osseointegration, fracture union, and stem subsidence were 98.6%, 98.6%, and 6.9%, respectively, at latest follow-up (mean follow-up 27.0 months (SD 22.4)). For patients with minimum one-year of follow-up, stem osseointegration, fracture union, and stem subsidence were 97.8%, 97.8%, and 6.5%, respectively.

Conclusion: Monoblock fluted stems can be an acceptable modality for the management of UCS B2 periprosthetic fractures in rTHAs due to high rates of stem osseointegration and survival, and the low rates of stem subsidence, and revision. Further research on the use of this stem for UCS B3 periprosthetic fractures is warranted to determine if the same conclusion can be made for this fracture pattern.

Fig. 1

a) Preoperative hip anteroposterior (AP) radiograph of 72-year-old male with Vancouver B2 periprosthetic fracture. b) Two-year postoperative AP hip radiograph with monoblock tapered fluted revision femoral stem with stem osseointegration.

Fig. 2

Radiological sequelae of a 58-year-old female patient with subsidence which stabilized over time. a) Immediate postoperative anteroposterior (AP) left hip radiograph demonstating a Vancouver B2 periprosthetic fracture revised with a monoblock tapered fluted stem and three cerclage wires. b) One-month postoperative AP left hip radiograph demonstrating minor femoral implant subsidence compared to initial stem position in a). c) One-year postoperative AP left hip radiograph with continued femoral implant subsidence d) Two-year postoperative AP left hip radiograph with stabilized femoral implant subsidence.

Fig. 3

Radiological sequelae of a 61-year-old female who did not achieve osseointegration. a) Preoperative anteroposterior (AP) hip radiograph of a Vancouver B2 fracture, as well as a femoral stem fracture following a minor trauma. b) Immediate postoperative AP pelvis radiograph demonstrating a revised femoral implant using a monoblock tapered fluted revision femoral stem and cerclage wires. c) Four weeks postoperative AP pelvis radiograph showing a femoral stem subsidence compared to the immediate postoperative radiograph. d) Immediate postoperative AP pelvis radiograph following re-revision surgery with a monoblock tapered fluted revision femoral stem.