Abstract
Background
Clinically evaluating the scapulothoracic joint is challenging. To identify scapular dyskinesis, clinicians typically observe scapular motion and congruence during self-directed upper extremity movements. However, it is unclear whether this method is reliable.
Questions/purposes
We therefore determined the interrater reliability of a scapular classification system in the examination of professional baseball players.
Methods
Seventy-one healthy uninjured professional baseball players between the ages of 18 and 32 years volunteered to participate. We used a digital video camera to film five repetitions of scapular plane elevation while holding a 2-pound weight. Four examiners then independently classified the motions on video into one of four types. Interrater reliability analysis using the kappa (k) statistic was performed for: (1) classifying each scapula into one of the four types; (2) classifying each scapula as being abnormal (Types I–III) or normal (Type IV); and (3) classifying both scapula as both being symmetric (both normal or both abnormal) or asymmetric (one normal, one abnormal).
Results
We found low reliability for all analyses. In classifying each scapula as one of the four types, reliability was k = 0.245 for the left limb and k = 0.186 for the right limb. When considering the dichotomous classifications (abnormal versus normal), reliability was k = 0.264 for left and k = 0.157 for right. For bilateral symmetry/asymmetric, reliability was k = 0.084.
Conclusion
We found low reliability of visual observation and classification of scapular movement.
Clinical Relevance
Current evaluation strategies for evaluating subtle scapular abnormalities are limited.
Level of Evidence
Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bourne DA, Choo AM, Regan WD, MacIntyre DL, Oxland TR. Three dimensional rotation of the scapula during functional movements: an in-vivo study in healthy volunteers. J Shoulder Elbow Surg. 2007;16:150–162.
Fleisig GS, Barrentine SW, Zheng N, Escamilla RF, Andrews J. Kinematic and kinetic comparison of baseball pitching among various levels of development. J Biomech. 1999;32:1371–1375.
Fleiss JL. Measuring nominal scale agreement among many raters. Psychol Bull. 1971;76:378–382.
Fleiss JL, Nee JCM, Landis JR. Large sample variance of kappa in the case of different sets of sample variance of kappa in the case of different sets of raters. Psychol Bull. 1979;86:974–977.
Forthomme B, Crielaard JM, Croisier JL. Scapular positioning in athlete’s shoulder. Sports Med. 2008;38:369–386.
Kibler WB. The role of the scapula in the overhead throwing motion. Contemp Orthop. 1991;22:525–532.
Kibler WB. The role of the scapula in athletic shoulder function. Am J Sports Med. 1998;26:325–337.
Kibler WB, Uhl TL, Maddux JW, Brooks PV, Zeller B, McMullen J. Qualitative clinical evaluation of scapular dysfunction: a reliability study. J Shoulder Elbow Surg. 2002;11:550–556.
Konda S, Yanai T, Sakurai S. Scapular rotation to attain the peak shoulder external rotation in tennis serve. Med Sci Sports Exerc. 2010;42:1745–1753.
Laudner KG, Stanek JM, Meister K. Differences in scapular upward rotation between baseball pitchers and position players. Am J Sports Med. 2007;35:2091–2095.
McClure PW, Michener LA, Sennett BJ, Karduna AR. Direct 3-dimensional measurement of scapular kinematics in vivo. J Shoulder Elbow Surg. 2001;10:269–277.
McClure PW, Tate AR, Kareha S, Irwin D, Zlupkp E. A clinical method for identifying scapular dyskinesis, Part 1: reliability. J Athl Train. 2009;44:160–164.
Myers JB, Laudner KG, Pasquale MR, Bradley JP, Lephart SM. Scapular position and orientation in throwing athletes. Am J Sports Med. 2005;33:263–271.
Nijs J, Roussel N, Struyf F, Mottram S, Meeusen R. Clinical assessment of scapular positioning in patients with shoulder pain: state of the art. J Manipulative Physiol Ther. 2007;30:69–75.
Oyama S, Myers JB, Wassinger CA, Ricci D, Lephart SM. Asymmetric resting scapular posture in healthy overhead athletes. J Athl Train. 2008;43:565–570.
Reid M, Elliott B, Alderson J. Lower-limb coordination and shoulder joint mechanics in the tennis serve. Med Sci Sports Exerc. 2008;40:308–315.
Sim J, Wright CC. The kappa statistic in reliability studies: use interpretation, and sample size requirements. Phys Ther. 2005;85:257–268.
Tate AR, McClure P, Kareha S, Irwin D, Barbe MF. A clinical method for identifying scapular dyskinesis, Part 2: validity. J Athl Train. 2009;44:165–173.
Uhl TL, Kibler WB, Gecewich B, Tripp BL. Evaluation of clinical assessment methods for scapular dyskinesis. Arthroscopy. 2009;25:1240–1248.
Author information
Authors and Affiliations
Corresponding author
Additional information
Each author certifies that he or she, or a member of their immediate family, has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.
Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.
This work was performed at Physiotherapy Associates Scottsdale Sports Clinic, Scottsdale, AZ, USA.
About this article
Cite this article
Ellenbecker, T.S., Ben Kibler, W., Bailie, D.S. et al. Reliability of Scapular Classification in Examination of Professional Baseball Players. Clin Orthop Relat Res 470, 1540–1544 (2012). https://doi.org/10.1007/s11999-011-2216-0
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11999-011-2216-0