Altered Scapular Time Series in Individuals With Subacromial Pain Syndrome

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Altered scapular movement is linked to subacromial pain syndrome (SASP).
• Previous analyses using discrete data reduction have limitations in addressing data collinearity and variability.
• Scapular translations remain under-investigated in symptomatic populations.

Purpose of the Study:

• To investigate and compare scapular rotation and translation during arm motions in individuals with and without SASP.
• To utilize principal component analysis (PCA) for a comprehensive kinematic analysis.

Main Methods:

• Scapulothoracic kinematics were assessed in 47 participants with SASP and 50 asymptomatic controls.
• Principal component analysis (PCA) was employed to analyze scapular rotation and translation during arm elevation and lowering.

Main Results:

• The SASP group showed significantly increased range of scapular anterior/posterior tilt during arm elevation and lowering (P = .01, P < .01).
• Increased range of scapular forward/backward translation was observed in the SASP group during arm lowering (P < .01).
• The symptomatic group exhibited reduced differences in anterior tilt angular velocities between arm lowering phases (P = .03).

Conclusions:

• Scapular anterior/posterior tilt motion, angular velocity, and forward/backward translation differ significantly between individuals with and without SASP.
• These findings underscore the importance of considering the entire arm movement for accurate kinematic assessment in SASP.
• The study provides valuable insights into the biomechanical alterations associated with subacromial pain syndrome.