Stereophotogrammetry for 3-Dimensional Kinematic Analysis in Rotator Cuff Tears: An Experimental Study Assessing Correlation with Clinical Scores

Background: Rotator cuff tears (RCTs) are a significant cause of shoulder pain and disability. In clinical practice, assessing a patient’s rotator cuff health status generally includes multiple questionnaire-based clinical scales. Optoelectronic motion capture systems, currently considered the gold standard, can be used to assess shoulder 3-dimensional (3D) kinematics quantitatively. Identifying new, hitherto unexplored relationships between kinematic parameters and clinical scores may help provide new insights into the management of patients with RCTs. Purpose: To investigate the correlations between the most common clinical scores for evaluating patients with RCT and objective kinematic measures retrieved by optoelectronic motion capture systems. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 102 patients with RCT were enrolled to evaluate correlations between clinical scores (eg, Shoulder Pain and Disability Index [SPADI] score and Oxford Shoulder Score [OSS]) and kinematic measurements (range of motion [ROM] and peaks) obtained using a 3D optoelectronic analysis system while performing 4 tasks. The relationship between these variables was evaluated using the Spearman correlation analysis. Results: The results revealed moderate to weak correlations between some kinematic variables and clinical scales, varying by the kinematic variable type, the task performed, and the specific clinical scale. A moderate correlation was found between the SPADI score and peaks during flexion (ρ = −0.485; P < .001) and abduction (ρ = −0.493; P < .001). Another moderate correlation was found between the OSS and ROM in flexion (ρ = −0.428; P < .001) and abduction (ρ = −0.415; P < .001); additionally, a moderate correlation was found between the OSS and peaks in flexion (ρ = −0.403; P < .001) and abduction (ρ = −0.407; P < .001). Other significant correlations were identified between kinematic measures and clinical outcomes, albeit of fair intensity, between visual analog scale score and ROM and peaks in flexion, abduction, and external rotation. Conclusion: This study emphasizes the necessity of a multidimensional approach to managing RCT, showing that only moderate correlations exist between some kinematic measurements and outcome scores, such as the SPADI score and OSS. Furthermore, measures like the American Shoulder and Elbow Surgeons and visual analog scale scores display even weaker, fair correlations. This discrepancy suggests the need for complementary tools to comprehensively evaluate a patient’s rotator cuff health status.