Arthroscopic lateral acromion resection (ALAR) optimizes rotator cuff tear relevant scapula parameters

Area of Science:

• Orthopedic Surgery
• Shoulder Biomechanics
• Radiographic Analysis

Background:

• Acromion index (AI), critical shoulder angle (CSA), and lateral acromion angle (LAA) predict degenerative rotator cuff tears.
• Unfavorable values of these parameters are linked to suboptimal deltoid force vectors.
• Arthroscopic lateral acromion resection (ALAR) is investigated for optimizing these radiological parameters.

Purpose of the Study:

• To evaluate the effectiveness of arthroscopic lateral acromion resection (ALAR) in optimizing shoulder radiological parameters.
• To assess the impact of ALAR on acromion index (AI), critical shoulder angle (CSA), and lateral acromion angle (LAA).

Main Methods:

• The ALAR procedure was performed on eight fresh frozen cadaver shoulders.
• Radiographs (true a.p. and axial) were taken pre- and post-intervention for radiological evaluation.
• A 1 cm segment of the lateral acromion was resected, and the deltoid insertion integrity was confirmed.

Main Results:

• Mean AI significantly reduced from 0.62 ± 0.11 to 0.40 ± 0.15 (p=0.012).
• Mean CSA significantly reduced from 35.0° ± 7.65° to 25.12° ± 8.29° (p=0.018).
• LAA showed no significant change (76.5° ± 14.02° vs. 82.13° ± 8.93°, p=0.107).
• No macroscopic injury to the deltoid insertion was observed.

Conclusions:

• ALAR effectively optimizes the radiographic parameters AI and CSA.
• The procedure achieves significant improvements without causing macroscopic discontinuity of the deltoid insertion.
• ALAR presents a potential method for improving shoulder biomechanics related to rotator cuff health.