Are you worried about Alzheimer’s and brain decline? Then you should worry about your knee pain and you should re-examine your thinking on knee replacement or any procedure that requires general or regional anesthesia especially if you are over 60.

 

Are you at greater risk for Alzheimer’s disease if you have a knee replacement surgery after the age of 60? Research says yes.

A study published earlier this year (February 2018) in the Journal of Alzheimer’s disease,(1) by University of Florida researchers, found that 23 percent of adults age 60 and older who underwent a total knee replacement experienced a decline in activity in at least one region of the brain responsible for specific cognitive functions. Fifteen percent of patients declined across all brain networks the team evaluated.

In a research summary issued by the Journal of Alzheimer’s Disease, the following points were made:

  • The University of Florida researchers conducted cognitive and brain imaging tests before and after surgery on 48 patients ages 60 and older undergoing a knee replacement.
    • Results were compared with age-matched adults who have knee osteoarthritis, but did not have surgery.
    • Participants who did not have surgery did not demonstrate any changes across the two brain scans,
    • but 23 percent of participants who had knee replacement surgery showed large declines in connectivity in at least one brain network when tested 48 hours after surgery.
    • “It was surprising to observe such significant effects of orthopedic surgery on the human brain,” said Haiqing Huang, Ph.D., one of the study’s lead authors.
  • Patients who were cognitively weaker before surgery – with worse working memory, slowed mental processing and evidence of brain atrophy as seen in imaging scans – demonstrated the biggest network declines after surgery.

This research was not the first to seemingly make a connection between cognitive decline and knee replacement surgery. In December 2016 in the journal Medicine, research lead by a team from Seoul National University made these observations on Postoperative cognitive dysfunction.

  • Postoperative cognitive dysfunction occurs in 25.8% of elderly patients (over the age of 60 year) within 1 week after surgery and in 9.9% of patients between 1 week and 3 months after surgery.
  • Although various factors including the types of anesthesia and surgery, comorbidities (numerous and other health problems the patient has), and prior to the surgery conditions may contribute to Postoperative cognitive dysfunction, why they occur is still not known. But they do occur.

The researchers found their evidence concerning enough that they suggest that some patients should be given more extensive neurological testing before knee replacement surgery.(2)

Over 65? Living in an adult community? What painkillers may or may not do to your brain

University researchers in Israel visited people, over age 65, who lived in an adult community. What they wanted to explore was how many of these 65+ people lived with chronic pain and what the chronic pain was doing to their health. Among the things that the researchers looked at was how chronic pain affected cognitive function.

These are the findings they published in the June 2018 issue of the Journal of Pain Research.(3)

  • More than half of the study participants reported pain that lasted for at least 3 months.
  • 94% of patients with chronic pain reported at least a moderate severity of pain and almost 60% complained of severe or very severe pain that had a negative effect on their daily activity.

The cognitive function connection: The use of painkillers – does it make cognitive function better or worse?

  • The study notes that past studies have raised an important question as to the association between painkillers administered for chronic pain and cognitive impairment:
    • in some cases, painkillers can cause cognitive impairment,
    • while in others, not only does analgesic therapy not cause cognitive impairment but it might even improve it.
    • However, only 41.4% study participants with chronic pain took painkillers. The question, were doctors afraid to offer painkiller prescription or were people declining the medication to prevent sluggishness? (3)

1 Huang H, Tanner J, Parvataneni H, Rice M, Horgas A, Ding M, Price C. Impact of total knee arthroplasty with general anesthesia on brain networks: cognitive efficiency and ventricular volume predict functional connectivity decline in older adults. Journal of Alzheimer’s Disease. 2018 Jan 1;62(1):319-33. [Google Scholar]

2 Jeon YT, Kim BG, Park YH, Sohn HM, Kim J, Kim SC, An SS, Kim S. Postoperative cognitive changes after total knee arthroplasty under regional anesthesia. Medicine. 2016 Dec;95(52). [Google Scholar]

3 Liberman O, Freud T, Peleg R, Keren A, Press Y. Chronic pain and geriatric syndromes in community-dwelling patients aged ≥65 years. Journal of Pain Research. 2018;11:1171-1180. doi:10.2147/JPR.S160847. [Google Scholar]

 

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