Prior TKR or Revision THR Causes Increased Periprosthetic Fractures

Periprosthetic fractures are especially common in patients with prior total knee replacement or revision total hip replacement a decade after primary total hip replacement, according to study results.

Researchers identified 58,521 Medicare beneficiaries who had elective primary total hip replacement (THR) for non-fracture diagnoses between July 1995 and June 1996 and followed them using Medicare Part A claims data through 2008. Using ICD-9 codes, researchers identified periprosthetic femoral fractures occurring from 2006 to 2008. The incidence density method was used to calculate the annual incidence of periprosthetic femoral fractures, and Cox proportional hazards models were used to identify risk factors for periprosthetic fracture. The risk of hospitalization during the subsequent year was also calculated.

Overall, 55 percent of patients who had elective primary THR between July 1995 and June 1996 survived until January 2006, with 0.7 percent of these patients developing a periprosthetic femoral fracture between 2006 and 2008. The researchers found an annual incidence of periprosthetic fractures of 26 per 10,000 person-years among these individuals.

According to Cox proportional hazards models, patients had a greater risk of periprosthetic fracture after having a total knee replacement or a revision total hip replacement between the primary THR and 2006. The researchers found a three-fold higher risk of hospitalization in the subsequent year among THR patients who sustained periprosthetic femoral fracture compared with patients without fractures.

“These data will help clinicians as they portray to patients and their families the long-term concerns associated with living with a hip implant,” the researchers wrote. “The message is that periprosthetic fractures are relatively rare, though more frequent in patients with multiple implants. Further, these fractures are typically associated with the need for considerable subsequent medical care, as they are accompanied by a much greater risk hospitalization in the subsequent year than experienced by THR recipients who did not have hip fracture.”