Low mortality risk following knee and hip replacement

According to a new study published in the January 2010 issue of the Journal of Bone and Joint Surgery (JBJS), the risk of early postoperative mortality -- or death following surgery -- was slightly increased for the first 26 days after the elective surgery. The risk of mortality was estimated to be 0.1 percent. The size of the study and the precise statistical tools used show the increase in early postoperative mortality was highest immediately after the operation. Then, 26 days after the surgery, the increased risk of death was negligible.

"Previous studies suggesting that increased mortality exists for as long as 60 or 90 days post hip or knee replacement surgery may be wrong," said lead author of the study, Stein Atle Lie, PhD, MSc and professor in the Department of Surgical Sciences at the University of Bergen, Norway who led the study with colleagues from the Department of Orthopaedic Surgery, and the Norwegian Arthroplasty Register at the Haukeland University Hospital in Bergen, Norway. "We believe the risk is tied to a much shorter duration."

The study included data on 81,856 patients with a total knee replacement and 106,254 patients with a total hip replacement from the Australian Orthopaedic Joint Replacement Registry and the Norwegian Arthroplasty Register. Only patients between 50 and 80 years of age with osteoarthritis were included.

The study found the most important risk factors for increased early postoperative mortality were:

• Male gender; and
• Age, older than 70 years old.

"This very low postoperative mortality after hip and knee replacements should be reassuring for patients considering these surgeries," explains study co-author Lars B. Engesaeter, MD, PhD and Head of Norwegian Arthroplasty Register, Haukeland University Hospital in Bergen, Norway.

People considering hip or knee replacement should talk to their orthopaedic surgeon about any added risk in relation to their age and follow recovery guidelines closely.

"We conducted this study to help people contemplating hip or knee replacement," continues Dr. Lie. "As with all surgeries, there is some increased risk of postoperative mortality. However, we were pleased to find the mortality rate is so minimal -- less than one percent -- following hip and knee replacements."