Shoulder pain across more movements is not related to more rotator cuff tendon findings in people with chronic shoulder pain diagnosed with subacromial pain syndrome.

INTRODUCTION: People with chronic shoulder pain commonly report pain during arm movements in daily-life activities. Pain related to movement is commonly viewed as an accurate representation of tissue damage. Thus, when a person reports pain across a variety of movements, this is often understood as indicative of greater damage. OBJECTIVES: We aimed to investigate if movement-related pain that occurs across a wider variety of movements was associated with the number or severity of rotator cuff tendons reported as abnormal on a magnetic resonance imaging (MRI). To answer this question, this study was designed in 3 phases. METHODS: We recruited 130 individuals with chronic shoulder pain diagnosed with subacromial pain syndrome. First, a list of daily functional activities commonly reported as painful by people with chronic shoulder pain was generated from 3 well-established outcome measures with 30 individuals and a measurement tool was developed with data from further 100 individuals, which demonstrated to have acceptable content validity, construct validity, internal consistency, interrater reliability, and structural validity. Multiple linear regression was then used to evaluate the hypotheses of the study. A direct acyclic graph was used to select variables for linear regression modelling. RESULTS: There was no association between movement-related pain occurrence across movements and the MRI findings. CONCLUSION: Our study provides evidence that neither the number of rotator cuff tendons reported as abnormal nor the severity of each tendon imaging finding were associated with pain occurrence across movements and activities commonly perceived as painful by people with chronic shoulder pain.

Distorted distance perception to reachable points in people with chronic shoulder pain.

Perception is not simply a carbon copy of the real world, but is subject to distortions that may reflect protective drive. This study aimed to investigate whether people with chronic shoulder pain show perceptual distortions of space and body that may promote protective behavior. Eighty-four people with shoulder pain and 51 healthy controls participated. Participants estimated (1) distances to points on a cork-board within and outside reaching distance, and (2) the perceived length of their own arms. A novel measure of movement-related pain was also used to determine whether movement-related pain relates to perceptual distortion. Overall, distance and arm length estimates did not differ between groups, nor did participants perceive their arms to be of different length. However, a moderate correlation between movement-related pain and the index of distance perception was found within the pain group, specifically for distance estimates to points within reach. Our results suggest that distorted perception is not a typical consequence of chronic shoulder pain; however, that it may occur in cases where pain is strongly linked to movement. Our findings have implications for understanding avoidance of movement in people with persistent pain.