Classification and Morphological Parameters of the Scapular Spine: Implications for Surgery

Area of Science:

• Orthopedic surgery
• Anatomy
• Biomechanics

Background:

• Scapular spine (SS) fractures are a significant complication of reverse total shoulder arthroplasty, leading to poor clinical outcomes and increased revision rates.
• These fractures, including those involving the acromion, account for 6% to 23% of all scapula fractures.

Purpose of the Study:

• To classify the scapular spine (SS) based on osteologic features.
• To present specific geometrical parameters for each SS type.
• To understand the anatomical variance of SS morphology relevant to surgical fixation and fracture susceptibility.

Main Methods:

• Collection and morphological classification of 319 intact dry scapulae.
• Identification and description of nine bony landmarks relevant to scapular fixation.
• Analysis of shape, thickness, and complexity of the scapular spine.

Main Results:

• Five distinct types of scapular spines were identified.
• Type 1 (Fusiform shape) was most prevalent (47.17%), followed by Type 5 (Horizontal S-shape) (19.18%).
• Types 2 and 5 were found to be thinner and potentially more susceptible to fractures, while Types 1, 3, and 4 exhibited thicker landmark values.

Conclusions:

• The classification into five types highlights the significant anatomical variability of the scapular spine.
• Complex SS morphologies (Types 1 and 5) may complicate surgical approaches.
• Thinner SS types (2 and 5) are identified as potentially more vulnerable to fracture, informing surgical planning and implant design.