The finding has “important implications, since fear of movement can lead to decreased physical activity,” wrote Alexander H. Gunn, of Duke University in Durham, N.C., and colleagues. Because physical activity is an essential component to the management, individuals with fear of movement may experience poorer outcomes, the authors said.

Although most of the study participants considered activity to be safe for them in a global sense, “a substantial proportion feared injury as a consequence of physical activity.”

For the study, now online in Arthritis Care & Research, 350 patients enrolled in the PATH-IN (Physical THerapy versus INternet-Based Exercise Training for Patients with Knee Osteoarthritis) study had data collected at baseline, prior to randomization. Each patient completed the Brief Fear of Movement measure, which consists of six items scored on a four-point scale from “strongly agree” to “strongly disagree.” Total scores range from 6 to 24, with higher scores indicating greater fear. The mean age of the study participants was 65.3, and 71.7% were female.

A total of 77% agreed or strongly agreed with at least one item on the scale, indicating some level of fear of movement. For example, 24.5% either agreed or strongly agreed with the statement “I am afraid that I may injure myself if I exercise,” 43.3% either agreed or strongly agreed with the statement “If I were to try to overcome it, my pain would increase,” 42.0% either agreed or strongly agreed with the statement “I am afraid that I might injure myself accidentally,” and 58.2% either agreed or strongly agreed with the statement “Simply being careful that I do not make unnecessary movements is the safest thing I can do to prevent pain from worsening.”

Previous evidence showed that individuals who experience pain-related fear are likely to engage in avoidance behaviors — specifically, avoidance of movement and physical activity, Gunn et al noted. “Although avoidance of potentially injurious movements is important in OA, and joint protection strategies should be encouraged as part of overall disease management, some individuals may avoid movement in general to minimize risk of pain exacerbation.”

A total of 41% agreed with one or two items on the scale, and 36% endorsed three or more items, indicating a high fear of movement.

In the multivariable model, the Knee Injury and Osteoarthritis Outcome Score (KOOS) (OR 0.61 per decade increase, 95% CI 0.44-0.85), the KOOS activities of daily living (ADL) subscale (OR 0.67 per 10-point increase, 95% CI 0.49-0.91) and the Patient Health Questionnaire depression scale (PHQ-8) (OR 1.15 per 1 unit increase, 95% CI 1.03-1.28) were associated with agreement on one or more of the Brief Fear of Movement items. “Directly addressing psychological variables could help to improve physical activity levels and clinical outcomes,” the researchers wrote.

Increasing age was associated with a lower likelihood of fear of movement (OR 0.79 per decade increase in age, 95% CI 0.66-0.95). “It is possible that older individuals have gained more experience with engagement in activity despite having a chronic pain condition, lessening their fear of movement.”

Patients with better function had less fear of movement: For each 10-unit increase in KOOS ADL there was a 14% reduction in the odds of having a higher degree of fear of movement (OR 0.86 per 10-unit increase in the KOOS ADL score, 95% CI 0.76-0.97). In addition, for each 10-unit increase in self-efficacy for exercise, there was a 13% reduction in the odds of having a higher degree of fear of movement (OR 0.87 per 10-unit increase, 95% CI 0.78-0.96).

For each one-unit increase in depressive symptoms, there was a 15% increase in the odds of having a higher degree of fear of movement (OR 1.15 per unit increase on the PHQ-8, 95% CI 1.08-1.22).

Limitations of the study cited by the authors were the cross-sectional nature of the data, the lack of de novo radiographs, and patient representation from a single clinical trial.

• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

LAST UPDATED 04.10.2017