TKA Outcomes for Age 80+ Similar to Younger Patients

CHICAGO — Patients 80 years or older undergoing primary total knee arthroplasty (TKA) have similar odds of complications compared with 65- to 79-year-old patients, an analysis of more than 1.7 million cases suggests.

Priscilla Varghese, MBA, MS, and an MD candidate at SUNY Downstate Health Sciences University in Brooklyn, New York, led the research, presented at the American Academy of Orthopaedic Surgeons (AAOS) 2022 Annual Meeting.

Priscilla Varghese

Varghese's team queried a Medicare claims database for the years 2005-2014 and analyzed information from 295,908 octogenarians and 1.4 million control patients aged 65-79 who received TKA.

Study group patients were randomly matched to controls in a 1:5 ratio according to gender and comorbidities, including chronic obstructive pulmonary disease, congestive heart failure, diabetes, peripheral vascular disease, and kidney failure.

Octogenarians were found to have higher incidence and odds of 90-day readmission rates (10.59% vs. 9.35%; odds ratio [OR], 1.15; 95% CI, 1.13 - 1.16; P < .0001).

Hospital stays were also longer (3.69 days ± 1.95 vs 3.23 days ± 1.83; P < .0001) compared with controls.

Reassuring Older Patients

However, Varghese told Medscape Medical News she was surprised to find that the older group had equal incidence and odds of developing medical complications (1.26% vs 1.26%; OR, 0.99; 95% CI, 0.96 - 1.03; P =.99).

"That's a really important piece of information to have when we are advising 80-year-olds to be able to say their risk of adverse outcomes is similar to someone who's 10 years, 15 years younger," she said. "It's really reassuring."

These results offer good news to older patients who might be hesitant to undergo the surgery, and good news in general as life expectancy increases and people stay active long into their later years, forecasting the need for more knee replacements.

The number of total knee replacements is expected to rise dramatically in the US.

In a 2017 study published in Osteoarthritis Cartilage, the authors write, "the number of TKAs in the US, which already has the highest [incidence rate] of knee arthroplasty in the world, is expected to increase 143% by 2050."

Dr Thomas Fleeter

Thomas Fleeter, MD, an orthopedic surgeon practicing in Reston, Virginia, who was not involved in the study, told Medscape Medical News this study reinforces that "it's OK to do knee replacements in elderly people, you just have to pick the right ones."

He pointed out that the study also showed that the 80-and-older patients don't have the added risk of loosening their mechanical components after the surgery, likely because they are less inclined than their younger counterparts to follow surgery with strenuous activities.

In a sub-analysis, revision rates were also lower for the octogenarians (0.01% vs 0.02% for controls).

Octogenarians who had TKA were found to have lower incidence and odds (1.6% vs. 1.93%; OR, 0.86; 95% CI, 0.83 - 0.88, P < .001) of implant-related complications compared with the younger group.

The increased length of stay would be expected, Fleeter said, because those 80-plus may need a bit more help getting out of bed and may not have as much support at home.

A total knee replacement can have the substantial benefit of improving octogenarians' ability to maintain their independence longer by facilitating driving or walking.

"It's a small and manageable risk if you pick the right patients," he said.

Demand for TKAs Rises as Population Ages

As patients are living longer and wanting to maintain their mobility and as obesity rates are rising, more older patients will seek total knee replacements, especially since the payoff is high, Varghese noted.

"People who undergo this operation tend to show remarkable decreases in pain and increases in range of motion," she said.

This study has the advantage of a more personalized look at risks of TKA because it stratifies age groups.

"The literature tends to look at the elderly population as one big cohort — 65 and older," Varghese said. "We were able to provide patients more specific data."

Varghese and Fleeter have disclosed no relevant financial relationships.

American Academy of Orthopedic Surgeons (AAOS) 2022 Annual Meeting: Poster P0120. Presented March 22, 2022.

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