Association Between Pain and Functional Disability in Patients with Shoulder Tendinopathy: A Cross-Sectional Study Using Patient-Reported and Performance-Based Measures

Abstract

Objectives: Shoulder tendinopathy is a common musculoskeletal disorder associated with persistent pain and functional disability. Although the relationship between pain and functional impairment has been investigated in other disorders, evidence in shoulder tendinopathy remains limited. Methods: This cross-sectional study included 36 patients with shoulder tendinopathy. Pain and self-reported function were assessed using the Shoulder Pain and Disability Index (SPADI); Shoulder Rating Questionnaire (SRQ); and a prespecified three-time-point Visual Analogue Scale (VAS) protocol. Affected-arm performance was evaluated using the Timed Functional Arm and Shoulder Test (TFAST). Spearman’s rank correlation coefficients (rs) were calculated using a Bonferroni-adjusted significance threshold of α = 0.007. Results: The SPADI Pain subscale was strongly associated with the SPADI Disability subscale (rs = 0.906, p < 0.001), while SPADI Total was strongly and inversely associated with SRQ Total (rs = −0.836, p < 0.001). Affected-arm TFAST performance was inversely associated with mid-test VAS pain recorded during the planned rest interval (rs = −0.574, p < 0.001). However, TFAST performance was not significantly associated with SPADI or SRQ scores after Bonferroni correction. Conclusions: Pain and self-reported disability were significantly associated, although some strong correlations involved overlapping components of patient-reported instruments. Performance-based function was associated with pain experienced during testing but not with SPADI or SRQ scores. Patient-reported and performance-based measures may capture related but distinct dimensions of shoulder function.