Ultrasonographic Assessment of Posterior Shoulder Capsule Thickness in Baseball Pitchers: A Validation Study
Year: 2025
Type: article
Study design: Observational Study
Abstract: BACKGROUND: A thickened posterior shoulder capsule may increase injury risk in baseball pitchers due to maladaptive shoulder biomechanics such as altered arthrokinematics, decreased internal rotation range of motion (ROM) and increased scapular upward rotation. While diagnostic ultrasound offers a reliable method of measuring posterior capsule thickness (PCT), it is currently unclear whether PCT thus measured is valid. HYPOTHESIS: Diagnostic ultrasound is a valid method for measuring PCT compared with magnetic resonance imaging (MRI). STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 4. METHODS: Asymptomatic baseball pitchers recently drafted into professional baseball from a single organization were enrolled during the 2021 to 2024 seasons. Pitchers underwent both diagnostic ultrasound and shoulder MRI on the same day to minimize any acute changes in PCT. All shoulder ultrasounds were performed with a 15-MHz linear transducer. Posterior capsule was identified as the tissue immediately lateral to the tip of the labrum between the humeral head and rotator cuff. PCT was measured on axial MRI scans by a musculoskeletal radiologist blinded to the ultrasound measurements. Agreement between modalities was evaluated through Pearson correlations and Bland-Altman analysis. RESULTS: < 0.001). The Bland-Altman plot demonstrated 95% limits of agreement of 0.55 mm between diagnostic ultrasound and MRI measurements of PCT. CONCLUSION: Measuring PCT with diagnostic ultrasound is a valid technique compared with the gold standard of MRI. CLINICAL RELEVANCE: Clinicians who wish to evaluate PCT in baseball pitchers may use this validated technique to quantify PCT and evaluate for potential contributors to glenohumeral internal rotation deficit.
Authors: Ryan W. Paul, Suzanne S. Long, Carlo Coladonato, Justin Ahrens, Aaron Hoback, Paul Buchheit, Joseph Rauch, Michael G. Ciccotti, Steven B. Cohen, Brandon J. Erickson, Stephen J. Thomas
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W4417447698