Analysis of scapular kinematics during active and passive arm elevation

Area of Science:

• Orthopedics
• Sports Medicine
• Biomechanics

Background:

• Early postoperative passive motion exercise following arthroscopic rotator cuff repair is a subject of ongoing debate.
• Understanding scapular kinematics and muscle activity during passive arm elevation is crucial for optimizing rehabilitation protocols.

Purpose of the Study:

• To evaluate scapular kinematics and muscle activities during passive arm elevation in healthy individuals.
• To provide data that may inform decisions regarding early postoperative rehabilitation after rotator cuff repair.

Main Methods:

• Three-dimensional scapular kinematics were assessed using electromagnetic sensors in 27 healthy subjects during active and passive arm elevation.
• Surface and intramuscular electrodes recorded the activity of seven shoulder muscles simultaneously.
• Scapular and glenohumeral motion were analyzed during different phases of arm elevation.

Main Results:

• Passive arm elevation significantly decreased scapular upward rotation between 30° and 100° compared to active elevation.
• Passive elevation led to a significant increase in the glenohumeral elevation angle in the mid-range.
• No significant differences in scapular posterior tilt or external rotation were found between active and passive elevation.

Conclusions:

• Passive arm elevation alters scapular kinematics, specifically reducing upward rotation and increasing glenohumeral motion.
• These findings suggest that passive arm elevation may not be ideal during the early postoperative period after rotator cuff repair.
• The study contributes to a better understanding of rehabilitation strategies for arthroscopic rotator cuff repair patients.