Jafarian Tangrood Z1, Sole G1, Cury Ribeiro D1
1University of Otago, Physiotherapy, Dunedin, New Zealand
Background: Measuring scapular orientations is challenging because of its anatomical form, complex motions, and overlying muscle and skin artefacts. One method for measuring the scapular orientations is to palpate scapula based on landmarks using a scapular locator, a hand-held measuring instrument. The scapular locator has been used as a gold standard to validate skin-fixed sensors on the scapula. However, to our knowledge, the between-day reliability and error of measurement of scapular locator has not been assessed.
Purpose: The purpose of this study was to assess the between-day reliability of scapular locator for measuring scapular orientations during arm elevation in the scapular plane.
Methods: Twenty-three asymptomatic individuals participated in the study. Scapular orientation was measured during two sessions with 24 hours interval. Three wireless inertial sensors were fixed on the thorax, upper arm and scapula locator with double-sided tape. One observer measured scapular orientations while participants sitting and holding their arms at 30°, 60°, 90° and 120° arm elevation in scapular plane. Three trials were performed for each position.
Analysis: We assessed the orientation of sensor locating on the scapular locator relative to thorax for each measurement. The sequence of rotations used to describe orientation of scapular locator sensor was YZX. Internal/external rotation occurred around the Y axis, upward/downward rotation around Z axis, and anterior/posterior tilt around the X axis. In each position of arm elevation, the between-day reliability was assessed using interclass correlation coefficients (ICC) and standard error of measurement (SEM).
Results: At 30° of arm elevation, poor ICCs (0.05 to 0.33) were found for all scapular orientations. Between 60° and 120° of arm elevation, ICCs ranged from 0.60 to 0.79 for scapular internal/external rotation, 0.68 to 0.87 for scapular upward/downward rotation, and from 0.46 to 0.61 for scapular anterior/posterior tilt. At 30° of arm elevation, SEMs were relatively large (5.5° - 6°) compared to the mean recorded values for all scapular orientations. Between 60° and 120° of arm elevation, the largest SEM (2.9° - 4.3°) was calculated for scapular internal/external rotation and the lowest SEM (2.8° - 3.1°) was found for scapular upward/downward rotation.
Conclusion(s): At 30° arm elevation, we observed poor reliability with high measurement error for scapular orientation. From 60° to 120° of arm elevation, we found higher relative reliability (ICCs) for scapular upward/downward and internal/external rotation than scapular anterior/posterior tilt. However, we indicated lower error of measurement for scapular upward/downward rotation and anterior/posterior tilt than scapular internal/external rotation. This means that from 60° to 120° of arm elevation, caution should be used when presenting scapular internal/external rotation.
Implications: The results define the reliability of scapular orientations measurements using a scapular locator. These results will inform how to interpret findings from studies assessing changes in scapular orientations over a period of time.
Keywords: Scapular orientation, Inertial sensor, Scapular locator
Funding acknowledgements: This study was part of a PhD project of the candidate Zohreh Jafarian Tangrood, supported by University of Otago PhD-Scholarship.
Purpose: The purpose of this study was to assess the between-day reliability of scapular locator for measuring scapular orientations during arm elevation in the scapular plane.
Methods: Twenty-three asymptomatic individuals participated in the study. Scapular orientation was measured during two sessions with 24 hours interval. Three wireless inertial sensors were fixed on the thorax, upper arm and scapula locator with double-sided tape. One observer measured scapular orientations while participants sitting and holding their arms at 30°, 60°, 90° and 120° arm elevation in scapular plane. Three trials were performed for each position.
Analysis: We assessed the orientation of sensor locating on the scapular locator relative to thorax for each measurement. The sequence of rotations used to describe orientation of scapular locator sensor was YZX. Internal/external rotation occurred around the Y axis, upward/downward rotation around Z axis, and anterior/posterior tilt around the X axis. In each position of arm elevation, the between-day reliability was assessed using interclass correlation coefficients (ICC) and standard error of measurement (SEM).
Results: At 30° of arm elevation, poor ICCs (0.05 to 0.33) were found for all scapular orientations. Between 60° and 120° of arm elevation, ICCs ranged from 0.60 to 0.79 for scapular internal/external rotation, 0.68 to 0.87 for scapular upward/downward rotation, and from 0.46 to 0.61 for scapular anterior/posterior tilt. At 30° of arm elevation, SEMs were relatively large (5.5° - 6°) compared to the mean recorded values for all scapular orientations. Between 60° and 120° of arm elevation, the largest SEM (2.9° - 4.3°) was calculated for scapular internal/external rotation and the lowest SEM (2.8° - 3.1°) was found for scapular upward/downward rotation.
Conclusion(s): At 30° arm elevation, we observed poor reliability with high measurement error for scapular orientation. From 60° to 120° of arm elevation, we found higher relative reliability (ICCs) for scapular upward/downward and internal/external rotation than scapular anterior/posterior tilt. However, we indicated lower error of measurement for scapular upward/downward rotation and anterior/posterior tilt than scapular internal/external rotation. This means that from 60° to 120° of arm elevation, caution should be used when presenting scapular internal/external rotation.
Implications: The results define the reliability of scapular orientations measurements using a scapular locator. These results will inform how to interpret findings from studies assessing changes in scapular orientations over a period of time.
Keywords: Scapular orientation, Inertial sensor, Scapular locator
Funding acknowledgements: This study was part of a PhD project of the candidate Zohreh Jafarian Tangrood, supported by University of Otago PhD-Scholarship.
Topic: Education: clinical
Ethics approval required: Yes
Institution: University of Otago
Ethics committee: Human Ethics Committee (Health)
Ethics number: reference number H17/073
All authors, affiliations and abstracts have been published as submitted.
