Study finds how infections after hip replacement increases risk of death

The findings of the research were published in the Journal of Bone and Joint Surgery.

Researchers from ICES, Sunnybrook Research Institute, and the Department of Surgery at the Temerty Faculty of Medicine at the University of Toronto examined the long-term (10 year) mortality risk of PJI for 175,432 adults receiving their first hip replacement in Ontario, Canada. This is one of the largest studies to date of patients with PJI following total hip arthroplasty (THA). ICES and Arthritis Society Canada provided funding for this study.

About 1 in 7 Canadian adults live with osteoarthritis, a number that is expected to grow as baby boomers age and life expectancies increase. Joint replacement procedures can lessen pain and improve quality of life for people who are dealing with this progressive disease.

"Most hip replacement surgeries are very successful, but unfortunately, about one to two percent of patients develop infections of the prosthetic joint. It is well established that such infections impact patient health over the long-term, but this research provides compelling evidence that it can even lead to death," said lead author Dr. Raman Mundi, an assistant professor in Temerty Medicine's Department of Surgery and a surgeon-scientist in the Division of Orthopaedic Surgery at Sunnybrook Health Sciences Centre.

The researchers found that among adults receiving their first hip replacement from 2002 to 2021, 868 patients (0.5%) required further surgery for a PJI within one year of hip replacement.

Patients with a PJI within the first year had a significantly higher 10-year mortality rate than those who didn't develop an infection (11.4 per cent versus 2.2 per cent)

"Our findings underscore the need for arthroplasty surgeons and infectious disease experts to work together on prevention efforts and follow best practice guidelines for patient care," said senior author Dr. Bheeshma Ravi, an adjunct scientist with ICES, surgeon-scientist with the Division of Orthopaedic Surgery at Sunnybrook Health Sciences Centre and assistant professor of surgery at Temerty Medicine.

The authors provide several reasons for why they believe the association between PJI and mortality is likely causal and not correlational.

First is that the association was quite strong, with the authors controlling for variables such as age, sex, income and health status. Second is that there is precedent that major orthopaedic events (for example, hip fractures) can directly increase risk of mortality. And finally, this study builds on existing evidence that used smaller cohorts of patients and shorter follow-up times.

"Ultimately, we need to develop effective strategies to prevent and cure these infections to reduce the long-term risk to patients," added Ravi.

"Joint replacement surgery is the mainstay of definitive management for millions of patients living with end-stage osteoarthritis. Although the risk of infection is quite low for the individual patient, given that tens of thousands of hip replacements are performed annually in Canada, and 70% are directly due to arthritis, it is crucial from a public health perspective to find strategies that reduce infection risk even further. Funding this research has allowed us to quantify this risk and provides necessary data to inform future prevention strategies," said Dr Sian Bevan, Chief Science Officer at Arthritis Society Canada. (ANI)