Effects of Rotator Cuff Pathology and Physical Therapy on In Vivo Shoulder Motion and Clinical Outcomes in Patients With a Symptomatic Full-Thickness Rotator Cuff Tear

Abstract

Background: Physical therapy (PT) is often prescribed for patients with rotator cuff tears. The extent to which PT influences strength, range of motion (ROM), and patient-reported outcomes has been studied extensively, but the effect of PT on in vivo joint kinematics is not well understood. Purpose: To assess the influence of symptomatic rotator cuff pathology and the effects of PT on shoulder motion, strength, and patient-reported outcomes. Study Design: Controlled laboratory study. Methods: Twenty-five patients with a symptomatic rotator cuff tear and 25 age-matched asymptomatic control subjects were recruited. Shoulder motion was measured using a biplane radiography imaging system, strength was assessed with a Biodex dynamometer, and patient-reported outcomes were assessed using the Western Ontario Rotator Cuff Index and visual analog scale (VAS) pain scores. Data were acquired from the patients before and after 8 weeks of physical therapy. Data were acquired at 1 time point for the control subjects. Results: Compared with the control subjects, patients with a symptomatic rotator cuff tear had significantly worse pain/function scores ( P < .01); less ROM ( P < .01); lower abduction (ABD), external rotation (ER), and internal rotation (IR) strength ( P < .01); less scapulothoracic posterior tilt ( P = .05); and lower glenohumeral joint elevation ( P < .01). Physical therapy resulted in improved pain/function scores ( P < .01), increased ROM ( P < .02), increased scapulothoracic posterior tilt ( P = .05), increased glenohumeral joint elevation ( P = .01), and decreased acromiohumeral distance (AHD) ( P = .02). Conclusion: Compared with age-matched controls, patients had worse pain/function scores, less ROM, and lower ABD, ER, and IR strength. Patients also had less scapulothoracic anteroposterior tilt, less glenohumeral joint elevation, and an altered glenohumeral joint contact path. PT resulted in improved pain/function scores, increased ROM, greater posterior scapulothoracic tilt, increased glenohumeral joint elevation, an increased range of superoinferior joint contact, and a lower mean AHD. Of these differences, PT only returned scapulothoracic tilt to control levels. Clinical Relevance: This study documents the effects of PT on shoulder motion and conventional clinical outcomes. It is expected that understanding how changes in joint motion are associated with conventional clinical outcomes will lead to improved nonoperative interventions for patients with rotator cuff tears.