Total joint replacement is a proven treatment to relieve chronic knee pain, but there have been concerns raised that particles from the device may migrate to the brain and cause memory problems. New research from Rush University shows that may not be a worry.
In a study published by Acta Biomaterialia, researchers found that particles in some people with total joint replacements traveled to the brain but did not cause cognitive decline.
Researchers did find an association of cobalt, a key element of most implants, with more Alzheimer’s disease pathology in the brain.
The particles, called wear debris, are caused by friction and movement in the joint, or, in some cases, corrosion. The newer materials used in joint replacements today make this less likely to occur.
“Implants have a very specific combination of metals such as cobalt, and when they show up together in one particle in the brain in the exact same composition that the implant is, we know it can’t come from any other source,” said Robin Pourzal, PhD, associate professor and director of implant materials analysis.
“For years, we’ve known that particles can deposit in tissues surrounding the joint, but this is the first study to look at the particles deposited in the brain.”
In working with Puja Agarwal, PhD, in the Rush Alzheimer’s Disease Center, the team took a closer look at what was happening cognitively in this group of people
The study included data collected among 701 deceased participants in the ongoing Memory and Aging Project conducted by David Bennett, MD, which include older adults residing in the greater Chicago area. The participants had no dementia at the beginning of the study and were followed annually with cognitive assessments using a 19-test battery, a standard collection of memory and thinking skill tests.
A total of 229 people in the study had a total hip, knee or shoulder replacement. The control group was made up of 472 people who had no total joint replacement. Due to a higher likelihood of the metal cobalt being found in total hip replacement, the participants were studied in two groups: 146 with hip replacements and 83 with knee or shoulder replacements.
Pourzal notes that the collaboration was led by faculty members from the Department of Orthopedic Surgery, including leaders from Rush Orthopedic Research, in collaboration with colleagues from the Rush Alzheimer’s Disease Center and international partners.
“Total joint arthroplasty remains one of the most successful and life-changing interventions in modern medicine. But it does suggest that wear particles from the implant, particularly in certain hip replacements involving accelerated wear, may travel beyond the joint and warrant further study.”
For more than 35 years, researchers at the Rush Alzheimer's Disease Center have studied how to both treat and prevent dementia. The center's main areas of research are the neurological basis of the disease, risk factors and the improvement of diagnosis and treatment. The center’s Rush Memory Clinic offers patient care services that include neurological and psychological evaluations and consultation with Alzheimer’s specialists.
