Unicortical Locking Screws Provide Comparable Rigidity to Bicortical Compression Screws in Tranverse Mid-Shaft...

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Trauma surgery

Background:

• Mid-shaft clavicle fractures are common injuries.
• Fixation of these fractures carries a risk of neurovascular complications.
• Current fixation methods require careful consideration of biomechanical properties.

Purpose of the Study:

• To biomechanically compare bicortical compression and unicortical locked clavicle plate constructs.
• To evaluate the construct stiffness under various loading conditions.
• To determine the optimal fixation method for mid-shaft clavicle fractures.

Main Methods:

• Ten composite clavicle osteotomy specimens were used.
• Specimens were divided into two groups: bicortical compression and unicortical locking screws.
• Constructs were tested for axial rotation, anterior/posterior bending, and cephalad/caudal bending on a servohydraulic frame.

Main Results:

• Unicortical locking fixation showed significantly greater stiffness in anterior/posterior bending (p=0.001).
• No significant differences in stiffness were observed for axial rotation (p=0.581), cephalad bending (p=0.807), or caudal bending (p=0.182).
• Both fixation methods demonstrated robust performance under tested biomechanical loads.

Conclusions:

• Unicortical locking fixation provides comparable biomechanical rigidity to bicortical compression fixation for mid-shaft clavicle fractures.
• This suggests unicortical locking plates are a viable alternative, potentially reducing surgical risks.
• Further clinical studies are warranted to confirm these biomechanical findings.