Measurement of scapular prominence in symptomatic dyskinesis using a novel scapulometer: reliability and the relationship to shoulder dysfunction

Tsun-Shun Huang; Wen-Jou Chen; Wan-Yu Du; Jiu-Jenq Lin

doi:10.1016/j.jse.2020.01.069

Measurement of scapular prominence in symptomatic dyskinesis using a novel scapulometer: reliability and the relationship to shoulder dysfunction

J Shoulder Elbow Surg. 2020 Sep;29(9):1852-1858. doi: 10.1016/j.jse.2020.01.069. Epub 2020 Apr 1.

Authors

Tsun-Shun Huang¹, Wen-Jou Chen¹, Wan-Yu Du¹, Jiu-Jenq Lin²

Affiliations

¹ School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan.
² School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan; Division of Physical Therapy, Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: jiujlin@ntu.edu.tw.

PMID: 32247722
DOI: 10.1016/j.jse.2020.01.069

Abstract

Background: No previous studies have investigated whether the extent of scapular dyskinesis is associated with shoulder dysfunction. This study aimed (1) to establish the reliability of a scapulometer in patients with shoulder pain and (2) to investigate the related factors associated with shoulder dysfunction.

Methods: One hundred participants with symptomatic scapular dyskinesis were recruited. Twenty-one participants were involved in the reliability study to test the intrarater and inter-rater reliabilities of the scapulometer in patients with shoulder pain. After demographic data and self-reported Flexilevel Scale of Shoulder Function (FLEX-SF) scores were recorded, all participants were measured with a scapulometer to determine the posterior displacement of the root of the spine (ROS) and the inferior angle (IFA) of the scapula from the thorax. Next, the participants performed 5 trials of bilateral scapular plane elevation for scapular kinematics and electromyographic (EMG) data collection. Stepwise multiple linear regressions were used to determine the relationships between self-reported FLEX-SF scores and potential factors. In addition to scapular displacement, pain level, scapular kinematics, and EMG data were included as independent variables.

Results: The intrarater and inter-rater reliabilities of the scapulometer were excellent (intraclass correlation coefficient [ICC] = 0.93-0.97) and moderate to good (ICC = 0.74-0.81), respectively. The Bland-Altman plots showed no systematic bias between raters in the ROS and IFA measurements. Final stepwise multiple regression models showed that more ROS distance, higher serratus anterior activity, and lower pain level during arm elevation were associated with higher shoulder function (total R² = 0.253).

Conclusion: The reliability of the scapulometer in patients with shoulder pain is moderate to excellent. Scapular dyskinesis may be a compensatory strategy to avoid shoulder pain and improve shoulder function.

Keywords: Scapular dyskinesis; function; kinematics; muscle activation; regression; reliability.

MeSH terms

Adult
Biomechanical Phenomena / physiology
Electromyography
Female
Humans
Male
Physical Examination / instrumentation*
Range of Motion, Articular / physiology*
Reproducibility of Results
Scapula / physiopathology*
Shoulder Joint / physiopathology*