A Clinical Method for Identifying Scapular Dyskinesis, Part 1: Reliability

Abstract

Context: Shoulder injuries are common in athletes involved in overhead sports, and scapular dyskinesis is believed to be one causative factor in these injuries. Many authors assert that abnormal scapular motion, so-called dyskinesis, is related to shoulder injury, but evidence from 3-dimensional measurement studies regarding this relationship is mixed. Reliable and valid clinical methods for detecting scapular dyskinesis are lacking.Objective: To determine the interrater reliability of a new test designed to detect abnormal scapular motion.Design: Correlation design using ratings from multiple pairs of testers.Setting: University athletic training facilities. Videotapes from randomly chosen participants were subsequently viewed and independently rated for the presence of scapular dyskinesis by 6 raters (3 pairs), with each pair rating 30 different participants. Raters were trained to detect scapular dyskinesis using a self-instructional format with standardized operational definitions and videotaped examples of normal and abnormal motion.Main Outcome Measure(s): Scapular dyskinesis was defined as the presence of either winging or dysrhythmia. Right and left sides were rated independently as normal, subtle, or obvious dyskinesis. We calculated percentage of agreement and weighted kappa (k w ) coefficients to determine reliability.Results: Percentage of agreement was between 75% and 82%, and k w ranged from 0.48 to 0.61.Conclusions: The test for scapular dyskinesis showed satisfactory reliability for clinical use in a sample of overhead athletes known to be at increased risk for shoulder symptoms.Key Words: shoulder, upper extremity, kinematics, assessment Key Points N Trained athletic trainers and physical therapists can recognize and distinguish between abnormal scapular movement patterns and normal patterns in young, athletically active adults.N The scapular dyskinesis test provides a reliable method for clinical examination of overhead athletes.

Reliability of Scapular Classification in Examination of Professional Baseball Players

“…First, scapular function and motion were not assessed on these players while performing their sport-specific movements such as throwing or pitching. Instead, a clinical method of scapular evaluation was used that involved elevation of the shoulder in the scapular plane using a 2-pound weight as has been advocated and studied elsewhere in the clinical and experimental literature [8,12,18,19]. Second, the use of video recording and capture of the upper extremity movements rather than live evaluation may have limited the interpretation of scapular outline and full appreciation of some aspects of human scapular motion that are better captured with live observation.…”

“…McClure et al [12] videotaped a sample of 142 uninjured athletes using the motions of flexion and coronal plane abduction with a 3-to 5-pound weight. Multiple raters viewed the videotape recording and rated the scapula as normal, subtle, or obvious dyskinesis.…”

“…They identified satisfactory reliability using this scapular classification system in overhead athletes. Tate et al [18] performed an additional study to validate the scapular classification system used in the study by McClure et al [12] using 66 of the same 142 subjects clinically analyzed in the McClure et al study. Using threedimensional electromagnetic kinematic testing, Tate et al [18] revealed less scapular upward rotation and less clavicular elevation in subjects classified with obvious dyskinesis compared with those classified with normal scapular motion.…”

“…Five full repetitions were performed and used for observation and analysis. This scapular test has been recommended and used in the literature for evaluating scapular humeral rhythm in athletes and in patients with glenohumeral dysfunction [7,8,12,18,19].…”

“…These movements, although objectively measurable in the laboratory setting with complex instrumentation such as three-dimensional tracking [1,9,11], are typically evaluated by clinicians in patients with shoulder dysfunction using only visual observation. Clinical decision-making regarding the presence or absence of scapular dysfunction or dyskinesis is made on that basis [5,12,18]. Various authors [6][7][8] defined scapular dyskinesis as ''an observable alteration of the position and motion of the scapula relative to the thoracic cage.''…”