The effects of pain science education plus exercise on pain and function in chronic Achilles tendinopathy: a blinded, placebo-controlled, explanatory, randomized trial

Abstract

Exercise is the standard of care for Achilles tendinopathy (AT), but 20% to 50% of patients continue to have pain following rehabilitation. The addition of pain science education (PSE) to an exercise program may enhance clinical outcomes, yet this has not been examined in patients with AT. Furthermore, little is known about how rehabilitation for AT alters the fear of movement and central nervous system nociceptive processing. Participants with chronic AT (N = 66) were randomized to receive education about AT either from a biopsychosocial (PSE) or from a biomedical (pathoanatomical education [PAE]) perspective. Simultaneously, all participants completed an exercise program over 8 weeks. Linear mixed models indicated that there were no differences between groups in (1) movement-evoked pain with both groups achieving a clinically meaningful reduction (mean change [95% CI], PSE: -3.0 [-3.8 to -2.2], PAE = -3.6 [-4.4 to -2.8]) and (2) self-reported function, with neither group achieving a clinically meaningful improvement (Patient-Reported Outcomes Measurement Information System Physical Function-PSE: 1.8 [0.3-3.4], PAE: 2.5 [0.8-4.2]). After rehabilitation, performance-based function improved (number of heel raises: 5.2 [1.6-8.8]), central nervous system nociceptive processing remained the same (conditioned pain modulation: -11.4% [0.2 to -17.3]), and fear of movement decreased (Tampa Scale of Kinesiophobia, TSK-17: -6.5 [-4.4 to -8.6]). Linear regression models indicated that baseline levels of pain and function along with improvements in self-efficacy and knowledge gain were associated with a greater improvement in pain and function, respectively. Thus, acquiring skills for symptom self-management and the process of learning may be more important than the specific educational approach for short-term clinical outcomes in patients with AT.

Figure 1.

Consolidated Standards of Reporting Trials (CONSORT) flow chart of the study participants with Achilles tendinopathy (AT) through the clinical trial comparing Pain Science Education (PSE) plus exercise to Pathoanatomical Education (PAE) plus exercise.

Figure 2.

The exercise progression included 3 phases: isometric, heel raise, and spring. The week that participants started the second 2 phases depended on individualized criteria. Each phase built on the previous phase yet was unique due to the addition of new exercises at a specified dose and frequency.

Figure 3.

Changes in (A) pain, (B) self-reported function, and (C) fear of movement with the Tampa Scale of Kinesiophobia (TSK-17), (D) performance-based function with the maximum number of single-leg heel raises, and (E) central nervous system processing of nociceptive input with conditioned pain modulation (CPM) over time and by group (pathoanatomical education [PAE], pain science education [PSE]). Statistically significant improvements over time are indicated by bars with an asterisk (*). PROMIS, Patient-Reported Outcomes Measurement Information System.