Modular Fluted Tapered Stems in Periprosthetic Femoral Fractures: Curved Stems are Protective Against Intraoperative Fracture and Postoperative Subsidence.

Abstract

Modular fluted tapered (MFT) stems are widely used to treat periprosthetic femoral fractures (PFFs). This study aimed to report the clinical and radiographic outcomes of revision hip arthroplasty using straight or curved MFT stems in patients who have PFFs. We reviewed revision hip arthroplasties performed using MFT stems for PFFs at a single institution. Of the 101 patients (101 hips) identified, 89 (89 hips) who satisfied a minimum follow-up of two years were included. Fractures were classified as Vancouver types B2 and B3 in 68 and 21 patients, respectively. Straight and curved distal stems were used in 55 and 34 hips, respectively. The amount of stem subsidence and final implant stability were radiographically assessed. Multivariate logistic regression analyses were performed to identify independent factors associated with additional intraoperative fracture and stem subsidence. The mean follow-up duration was 10 years (range, two to 22). The mean modified Harris Hip Score was 83 points (range, 45 to 100) at the final evaluation. During revision surgery, additional diaphyseal split fractures occurred in 10 hips (11.2%) and cortical perforations in five (5.6%). The mean stem subsidence was 3.5 mm. In multivariate regression analyses, the use of curved MFT stems was associated with a lower risk of additional intraoperative fracture (P = 0.024) and stem subsidence of ≥ five mm (P = 0.032). Overall, three re-revision surgeries were performed; two for periprosthetic joint infection and one for aseptic stem loosening. Implant survivorship free of any re-revision surgery was 94.6% at 10 years. Revision hip arthroplasty using MFT stems demonstrated excellent outcomes in PFFs with high revision-free survivorship at 10 years. The use of curved MFT stems was associated with a lower risk of intraoperative fracture and postoperative stem subsidence.