EMBARGO LIFTS: Saturday, Oct. 20, 4:30 p.m. (CT)
Media Contact: Monica McDonald
Newsroom – (312) 949-8822
Office – (404) 633-3777 ext. 332
HIGHER INTENSITY WALKING MAY LOWER RISK OF KNEE REPLACEMENT IN PEOPLE WITH OA
Newswise — CHICAGO – Patients with knee osteoarthritis who walk at a moderate-to-vigorous intensity may lower their risk of total knee arthroplasty, or joint replacement surgery, according to new research findings presented this week at the 2018 ACR/ARHP Annual Meeting (Abstract #1166).
Osteoarthritis (OA) is a common joint disease that most often affects people in middle age or later. OA is a painful disease that affects the entire joint, involving the cartilage, joint lining, ligaments and bone. OA is characterized by the breakdown of the cartilage (the tissue that cushions the ends of the bones between joints), bony changes of the joints, deterioration of tendons and ligaments, and various degrees of inflammation of the joint lining (called the synovium).
This study was conducted to help answer the question: Does walking more increase a patient’s risk of structural worsening in the knee joint and total knee arthroplasty (TKA)? One reason for prior inconsistent, contradictory evidence in this area is that patients may walk at different intensities. Researchers at the University of Delaware conducted a study to learn more about the association of walking intensity with TKA risk over a five year period in adults with or at high risk of knee OA.
“We wanted to know if walking was helpful or harmful for getting a knee replacement for people who have knee OA,” said Hiral Master, PT, MPH, a PhD candidate in biomechanics and movement science at the University of Delaware and the study’s co-author. “Walking may exacerbate knee pain and further make things worse, but on the other hand, walking is helpful to build and maintain strength, and may prevent the development of difficulty functioning.”
The study used data from the Osteoarthritis Initiative (OAI), and included participants who did not have TKA at or before a 48-month follow-up visit. The researchers quantified time spent in different walking intensities by step cadence recorded by an accelerometer. They defined less than one step/minute as non-walking, 1-49 steps/minute as very light walking, 50-100 steps/minute as light walking, and more than 100 steps/minute as moderate to vigorous walking. They quantified time to TKA in months from the baseline visit date to the surgery date if it occurred in the subsequent five years, or at the 108-month visit. Any participants who did not have TKA at the 108-month visit or who were lost to follow-up were censored. The researchers examined the effects of replacing time spent not walking with walking at either very light, light or moderate-to-vigorous intensities with TKA risk over five years. They also repeated these analyses on just participants with radiographic and symptomatic knee OA.
At baseline, there were 1,854 participants without TKA who wore their accelerometer for at least four out of seven days. They had a mean age of 65 years, a mean body-mass index (BMI) of 28.4 and 55 percent were female. Over five years, 108 participants received a TKA. Those participants who replaced five minutes per day of non-walking time with five minutes per day of walking at moderate-to-vigorous intensity reduced their risk of TKA by 16 percent, the study’s findings showed. Very light and light intensity walking had no effect. Similar results were found when the researchers analyzed samples of patients with radiographic and symptomatic knee OA.
“Our findings suggest that small changes in walking behavior may delay the need for TKA in people with or at high risk of knee OA. Clinicians should consider encouraging their patients with or at high risk of knee OA to go for a brisk walk for five to 10 continuous minutes each and every day,” said Master.
This research was supported by the National Institutes of Health.
About the ACR/ARHP Annual Meeting
The ACR/ARHP Annual Meeting is the premier meeting in rheumatology. With more than 450 sessions and thousands of abstracts, if offers a superior combination of basic science, clinical science, tech-med courses, career enhancement education and interactive discussions on improving patient care. For more information about the meeting, visit https://www.rheumatology.org/Annual-Meeting, or join the conversation on Twitter by following the official #ACR18 hashtag.
About the American College of Rheumatology
The American College of Rheumatology is an international medical society representing over 9,400 rheumatologists and rheumatology health professionals with a mission to empower rheumatology professionals to excel in their specialty. In doing so, the ACR offers education, research, advocacy and practice management support to help its members continue their innovative work and provide quality patient care. Rheumatologists are experts in the diagnosis, management and treatment of more than 100 different types of arthritis and rheumatic diseases. For more information, visit www.rheumatology.org.
Abstract #: 1166
Friend or Foe: Does Walking at Higher Intensities Increase or Decrease the Risk of Total Knee Arthroplasty over Five Years?
Hiral Master, Louise Thoma, Meredith Christiansen, Dana Mathews, Erin Macri, Melissa Ziegler, Joshua J. Stefanik and Daniel White, University of Delaware, Newark, DE
Background/Purpose: There is contradicting evidence whether walking more is associated with structural worsening and total knee arthroplasty (TKA). One reason for inconsistent findings is that walking can occur at different intensities. However, little is known about the association of walking intensity with the risk of TKA. The purpose of this study was to examine the extent to which walking intensity is associated with the risk of TKA over five years in adults with or at high risk of knee OA.
Methods: Using data from the Osteoarthritis Initiative (OAI), we included participants who did not have TKA at or before the 48-month follow-up visit, which we considered our study baseline. Time spent in different walking intensities was quantified by step cadence recorded by an accelerometer (Actigraph GT1M). We defined <1 step/min as non-walking, 1-49 steps/min as very-light, 50-100 steps/min as light, and >100 steps/min as moderate-to-vigorous intensities of walking. Time to TKA was quantified in months from the baseline visit date to TKA date if received in the subsequent five years, i.e., until the 108-month OAI visit. Participants without TKA at the 108-month OAI visit or lost to follow-up were censored. We examined effects of replacing time not walking with walking at very-light, light, or moderate-to-vigorous intensities with the risk of TKA over five years using isotemporal substitution within a Cox proportional hazard model. Specifically, we calculated hazard ratios (HR) and 95% confidence interval (CI) adjusted for potential confounders. We repeated analyses restricting our sample to participants with radiographic (ROA) and symptomatic (SxOA) knee OA (see Table).
Results: Of the 1854 participants without TKA at baseline and who wore the accelerometer for ≥ 4 days ([mean ± sd] age: 65.0 ± 9.1 years, BMI: 28.4 ± 4.8 kg/m2, 55% female), 108 (6%) participants received a TKA over five years. Replacing 5 minutes of non-walking time with 5 min of walking at moderate-to-vigorous intensity reduced the risk of TKA by 16% (HR 0.84, 95%CI [0.72, 0.98]). There was no effect for very-light and light intensity. We found similar results for ROA and SxOA only samples (see Table).
Conclusion: Replacing time not walking with walking at moderate-to-vigorous intensity was associated with not more but less risk of TKA over five years. Our findings suggest that small changes in walking behavior could delay the need for TKA in people with or at high risk of knee OA.
Disclosures: H. Master, None, L. Thoma, None, M. Christiansen, None, D. Mathews, None E. Macri, None, M. Ziegler, None, J. J. Stefanik, None, D. White, None