Incidence of Early Periprosthetic Hip Fractures in Patients Over Age 70 Years Following Primary Total Hip Arthroplasty Using a Novel Triple-Tapered Collared Femoral Stem.

Abstract

Periprosthetic hip fractures are a known complication following cementless total hip arthroplasty (THA), especially in elderly patients. A triple-tapered collared femoral stem was introduced to provide multidirectional contact, resist torsional forces, and distribute load to help reduce subsidence. The purpose of this study was to determine the incidence of periprosthetic femoral fractures with a novel triple-tapered collared femoral stem in a group of patients who were aged greater than 70 years undergoing primary THA. This was a multicenter retrospective analysis of patients who were aged greater than 70 years undergoing primary THA. There were 385 THAs that had a triple-tapered collared stem compared to 383 dual-tapered collarless stems. There were no differences between groups regarding sex and American Society of Anesthesiologists class. The dual-tapered group had a higher average body mass index than the triple-tapered group (29.9 versus 28.4, P < 0.01) and higher age (76.0 versus 75.2, P = 0.022). Overall revision rates, incidence of periprosthetic fractures, and complications were compared. There were seven (1.8%) early (less than one month) periprosthetic fractures in the dual-tapered group and one (0.26%) early fracture in the triple-tapered group (P = 0.038). The dual-tapered group had a longer follow-up and a higher overall revision rate of 5.7%, primarily due to prosthetic joint infection and periprosthetic fractures. There were four revisions in the triple-tapered collared group (1.0%, P < 0.01). The use of a novel triple-tapered collared stem was associated with a significant decrease in the incidence of periprosthetic fractures in patients who were aged greater than 70 years undergoing primary THA. Given the increased mortality of periprosthetic hip fractures in elderly patients, the results of this study appear promising and require additional follow-up to determine if the results are durable.