A Clinical Method for Identifying Scapular Dyskinesis, Part 2: Validity

Abstract

Context: Although clinical methods for detecting scapular dyskinesis have been described, evidence supporting the validity of these methods is lacking.Objective: To determine the validity of the scapular dyskinesis test, a visually based method of identifying abnormal scapular motion. A secondary purpose was to explore the relationship between scapular dyskinesis and shoulder symptoms.Design: Validation study comparing 3-dimensional measures of scapular motion among participants clinically judged as having either normal motion or scapular dyskinesis.Setting: University athletic training facilities. Patients or Other Participants: A sample of 142 collegiate athletes (National Collegiate Athletic Association Division I and Division III) participating in sports requiring overhead use of the arm was rated, and 66 of these underwent 3-dimensional testing.Intervention(s): Volunteers were viewed by 2 raters while performing weighted shoulder flexion and abduction. The right and left sides were rated independently as normal, subtle dyskinesis, or obvious dyskinesis using the scapular dyskinesis test. Symptoms were assessed using the Penn Shoulder Score.Main Outcome Measure(s): Athletes judged as having either normal motion or obvious dyskinesis underwent 3-dimensional electromagnetic kinematic testing while performing the same movements. The kinematic data from both groups were compared via multifactor analysis of variance with post hoc testing using the least significant difference procedure. The relationship between symptoms and scapular dyskinesis was evaluated by odds ratios.Results: Differences were found between the normal and obvious dyskinesis groups. Participants with obvious dyskinesis showed less scapular upward rotation (P , .001), less clavicular elevation (P , .001), and greater clavicular protraction (P 5 .044). The presence of shoulder symptoms was not different between the normal and obvious dyskinesis volunteers (odds ratio 5 0.79, 95% confidence interval 5 0.33, 1.89).Conclusions: Shoulders visually judged as having dyskinesis showed distinct alterations in 3-dimensional scapular motion. However, the presence of scapular dyskinesis was not related to shoulder symptoms in athletes engaged in overhead sports.

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.…”

“…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.…”

“…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. The study by Tate et al [18] demonstrated the important objective relationship identified between three-dimensional electromagnetic kinematic testing and observationally based scapular evaluation in overhead athletes.…”

“…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.''…”