Du W.-Y.1, Huang T.-S.1, Hsu K.-C.2, Lin J.-J.1
1National Taiwan University College of Medicine, School and Graduate Institute of Physical Therapy, Taipei, Taiwan, 2National Taiwan University, College of Engineering, Department of Mechanical Engineering, Taipei, Taiwan
Background: Scapula control is crucial in upper limb motion, winging and inferior angle prominence of scapula are believed to be key components for evaluation and treatment in rehabilitation of shoulder pathologies. Although some measurement instruments have been developed, lack of sufficient psychometric properties makes them difficult for clinical practice.
Purpose: A modified scapulometer was developed to measure scapula winging and inferior angle prominence. Psychometric properties of the instrument were analyzed.
Methods: Twenty-nine participants with scapular dyskinesis (23 ± 2.1 years old, 14 male, 26 right handed) were recruited. Modified scapulometer was designed to measure the posterior displacement distance from thorax to root of spine (ROS) and inferior angle (INF) of the scapula, respectively. All measurements were performed in natural sitting position with arms by side. Two raters measured the ROS and INF distance of scapula 3 times bilaterally. During the measurements, 2 raters were blinded to the results. Intraclass correlation coefficients (ICC) were calculated based on a repeated measure analysis of variance to determine intertester and intratester reliability. The standard error of measurement (SEM) was used to determine the measurement error. Additionally, FASTRAK Polhemus 3-D motion tracking system was used as a standard instrument for validation. Scapula position differences between dyskinesis and neutral positions were calculated, including scapula tilt, internal/external rotation and upward/downward rotation. Correlations between ROS and internal/external rotation and between INF and tilt were calculated to represent convergent validity. Correlations between ROS/INF and upward rotation of scapula represent divergent validity.
Results: The average ROS and INF displacement was 13.7 ± 5.0 mm and 12.5 ± 6.3 mm, respectively. The results showed excellent intra-rater and inter-rater reliability, ICC= 0.88-0.99 and 0.95-0.99 (SEM=0.7-0.8 mm), respectively. Convergent validity correlations were 0.35 and 0.19 for ROS/external rotation and INF/posterior tilt, respectively. Divergent validity correlations were 0.07 and 0.09 for ROS/upward rotation and INF/upward rotation, respectively.
Conclusion(s): The modified scapulometer had excellent reliability and sufficient validity to quantify winging and inferior angle prominence of scapula. Further research utilizing this measurement instrument is recommended.
Implications: The modified scapulometer is inexpensive and easy to access, designed to measure winging and inferior angle prominence of scapula. Application of this instrument in evaluation and treatment outcomes for patients with shoulder pathologies is suggested.
Funding acknowledgements: This research is supported by ministry of science and technology, MOST 104-2314-B-002-026-MY3, Taiwan.
Topic: Musculoskeletal: upper limb
Ethics approval: This research is approved by IRB committee at National Taiwan University Hospital, Taiwan.
All authors, affiliations and abstracts have been published as submitted.
