A prospective study of patients with shoulder pain and Mechanical Diagnosis and Therapy (MDT).

: A prospective observational cohort study was conducted to (1) determine the prevalence of Mechanical Diagnosis and Therapy (MDT) syndromes for patients with shoulder impairments and (2) report the interaction between MDT classification and clinical outcomes, including pain intensity and disability, at discharge.: Clinical outcome measures were completed at intake and discharge by 115 patients. A two-way mixed model analysis of variance with subsequent pairwise comparisons was done to examine differences in clinical outcomes between the following MDT classifications: Shoulder Derangement, Shoulder Dysfunction, and Other.: The primary findings were that (1) 44.3 (35.3, 53.4), 40.0 (31.0, 48.9), and 15.6 (9.0, 22.3) percent of patients' conditions were classified as Shoulder Derangement, Shoulder Dysfunction, and Other, respectively, (2) all groups managed via MDT methods made clinically significant improvements in disability and pain intensity at discharge, (3) a statistically significant difference in pain intensity at discharge was observed between the Shoulder Derangement and the Shoulder Dysfunction classifications ( = 0.01), and (4) patients with the Shoulder Derangement classification were discharged, on average, 35.3 days earlier than the Shoulder Dysfunction classification and 28.3 days earlier than the Other classification.: This study confirms previous reports that the Shoulder Derangement and Shoulder Dysfunction classifications are common and represent distinct clinical trajectories when assessed and managed via MDT methods.