A new study by UMass Chan Medical School faculty found that while adult patients from all age groups reported improvements following total knee arthroplasty (TKA, also called knee replacement), patients aged 55 and younger were found to have less improvement in pain, function and quality of life following surgery compared with patients 75 years and older.
“The literature had conflicting results about whether a difference in outcome based on patient age existed, so we felt this was an important area in which we could improve knowledge of outcomes following TKA,” said lead author David Ayers, MD, the Arthur M. Pappas, MD Chair in Orthopedics and distinguished professor of orthopedics & physical rehabilitation.
The paper was among a few impactful research presentations highlighted by the American Academy of Orthopaedic Surgeons at its 2023 annual meeting, held in Las Vegas in March.
The study analyzed 11,602 patients who underwent unilateral (one knee) TKA. Patients were segmented into cohorts by age: under 55, 55-64, 65-74 and 75 years and older. The team collected the following patient information prior to surgery and at three months and one year postoperative: detailed demographic data; medical and musculoskeletal comorbidity conditions; patient-reported outcome measures to determine the patients’ levels of pain, function and quality of life; and a short health survey that assessed the overall physical and emotional status of the patient.
“TKA is a life-changing operation, and this study shows it works extremely well in all four age groups,” said Dr. Ayers. “But when you compare the age groups in detail and focus on pain, in particular, the younger patients start at a different pain level when compared to the older patients.”
There had previously been a sense that younger patients needing TKA were typically healthy, fit people who tended to be athletes who had injured their knees, Ayers explained. “When we looked at this group carefully, however, that is not true,” he said. “The less than 55-year-olds were on the whole more obese than the older patient groups. They also had a higher incidence of being smokers and former smokers, and many of them exhibited a variety of other medical conditions.”
The youngest patients started with more pain and reported lower quality of life before surgery as well, compared with the oldest group. Ayers said that this may be related to the patients’ expectations based on what they see among peers their age.
Ayers said, “One of the take-home messages from this study is that it’s important for the surgeon and the surgical team to ask all patients—but particularly patients less than 55—what their expectations are regarding pain and activity level after TKA. The surgeon should set realistic expectations for after surgery, so patients know that their knees are not going to be completely pain free, but it’s going to be dramatically better than it was before surgery. The discussion should include what activities after TKA are appropriate and what sporting activities are not.”
This large study of patient data and patient-reported outcomes across a wide range of surgery settings in the United States is a product of UMass Chan’s role developing and managing a national consortium funded by the U.S. Agency for Healthcare Research and Quality, called FORCE-TJR (Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement). FORCE-TJR was launched in 2010 with an award of $12 million and includes a national network of 235 practices, including academic and community medical centers as well as private surgical centers.
Ayers said that FORCE-TJR’s focus on the voice of the patient through the use of patient-reported outcomes has become a standard of care across the U.S. in measuring surgical outcomes following knee replacement and will be required by federal regulators for all Medicare patients undergoing knee or hip replacement beginning in 2026.
