The usefulness of ultrasound in predicting outcomes in patients with shoulder pain: a prospective observational study

Objectives Shoulder pain is common but current clinical classification has limited utility. We aimed to determine whether groups of ultrasound-based shoulder pathologies exist and to evaluate outcomes according to identified groups and individual pathologies. Methods This was a prospective study of a community-based cohort with shoulder pain referred for their first ultrasound scan at a single radiology unit, with subsequent routine clinical care. Patient-reported outcomes were collected at baseline, 2 weeks and 6 months; standardized ultrasound reporting was employed. Latent class analysis (LCA) identified ultrasound pathology–based groups. Multiple linear regression analysis explored associations between baseline pathologies, subsequent treatment and Shoulder Pain and Disability Index (SPADI). Short-term response to corticosteroid injections was investigated. Results Of 500 participants (mean age 53.6 years; 52% female), 330 completed follow-up. LCA identified four groups: bursitis with (33%) or without (27%) acromioclavicular joint degeneration, rotator cuff tear (21%) and no bursitis/tear (19%). Total SPADI was higher at baseline for cuff tears (mean 55.1 vs 49.7–51.3; overall P = 0.005), but accounting for this, groups did not differ at 6 months (43.5 vs 38.5–40.5; P = 0.379). Baseline SPADI was the only predictor of 6-month SPADI retained by penalized modelling; neither LCA-derived ultrasound groups nor individual pathologies were selected. Response to baseline injection at week 2 did not differ between groups (mean SPADI 40.1–43.8; P = 0.423). Conclusion Ultrasound-based classification (groups or individual pathologies) of shoulder pain did not predict medium-term outcomes using current treatments. The role of routine diagnostic ultrasound for shoulder pain needs consideration; it may be useful to establish evidence-based therapies for specific pathologies