Acromioclavicular joint reconstruction using the LockDown synthetic implant: a study with cadavers

Area of Science:

• Orthopedic surgery
• Biomechanical analysis
• Anatomy

Background:

• Acromioclavicular (AC) joint dislocation is a common injury.
• Surgical treatments vary, with recent use of synthetic ligament devices.
• Non-native solutions require careful placement for optimal outcomes.

Purpose of the Study:

• To evaluate the impact of different clavicular anchorage points for the Lockdown device on AC joint dislocation reduction.
• To identify the optimal clavicular placement for the Lockdown device.
• To assess the added stability from coracoacromial ligament transfer.

Main Methods:

• Cadaveric study on seven fresh-frozen shoulders.
• Reconstruction of the AC joint using the Lockdown implant at four distinct clavicular anchorage points.
• Measurement of joint reduction and assessment of stability with and without coracoacromial ligament transfer.

Main Results:

• Anatomical reduction was achieved in all cases when the Lockdown device was anchored at the conoid tubercle.
• Placement 2 cm medial or lateral to the conoid tubercle resulted in irreducible dislocations.
• Placement 1 cm lateral to the conoid tubercle allowed reduction in four cases, but with difficulty.
• Anterior clavicle displacement persisted even with optimal Lockdown placement, but was managed by coracoacromial ligament transfer.

Conclusions:

• Precise clavicular anchorage of the Lockdown device is critical for anatomical reduction of AC joint dislocations.
• The conoid tubercle represents the optimal anchorage point for the Lockdown implant.
• Coracoacromial ligament transfer provides supplementary stability, addressing residual anterior clavicle displacement.