What is the recommended length of coracoid (coracoid process) needed for a Latarjet procedure?

Coracoid Length Requirements for Latarjet Procedure

A minimum coracoid length of approximately 17-22 mm is needed for the Latarjet procedure, though the specific requirement depends on the size of glenoid bone loss and the fixation method chosen.

Anatomic Dimensions of the Coracoid

• The mean usable coracoid length ranges from 16.8-23.9 mm across anatomic studies, with significant individual variation 1, 2, 3
• Coracoid width averages 13.6-15.0 mm and thickness averages 8.6-10.5 mm 1, 2, 3
• Approximately 46% of patients have a coracoid length less than 25 mm, making preoperative CT assessment critical 1

Matching Coracoid Length to Glenoid Defect

The adequacy of coracoid length depends on the extent of glenoid bone loss:

• For 20-25% glenoid bone loss: The coracoid graft successfully restores glenoid anatomy in 96% of cases 1
• For 30% glenoid bone loss: The coracoid adequately restores anatomy in only 79.2% of cases, indicating this may represent the upper limit for standard Latarjet 1
• The radius of curvature (ROC) of the coracoid undersurface (mean 13.6 mm) matches the intact glenoid ROC (mean 13.8 mm) in the congruent-arc technique, though substantial variation exists with up to 45% of specimens showing ROC mismatch 2, 3

Fixation Method Considerations

The choice of fixation implant significantly impacts the "safe distance" from the coracoid osteotomy:

• 4.5 mm screws: Safe positioning achieved in only 56% of cases 1
• 3.75 mm screws: Safe positioning in 85% of cases 1
• 3.5 mm screws: Safe positioning in 87% of cases 1
• 2.8 mm button fixation: Safe positioning in 98% of cases, providing the greatest safety margin 1, 3

The "safe distance" is defined as at least equal to the implant diameter between the fixation device and the coracoid osteotomy edge 1.

Critical Preoperative Planning

CT-based preoperative planning is essential to determine:

• Precise coracoid dimensions (length, width, thickness) 4, 5
• Extent of glenoid bone loss 4
• Optimal screw length to avoid suprascapular nerve injury (reported in up to 6% of cases) or bone block non-union (up to 20% of cases) 5
• Whether the available coracoid length is adequate for the planned reconstruction 1, 3

Modified Technique for Limited Coracoid Length

• The "LUtarjet" technique with limit unique coracoid osteotomy preserves the coracoacromial arch while using individualized flexible arthroscopic suture button fixation 4
• This approach allows for coracoid osteotomy as small as 8-10 mm with subscapularis splitting, potentially useful when coracoid length is limited 4

Key Clinical Pitfalls

• Population-specific variations exist: Indian populations show significantly smaller coracoid dimensions, with 2.7 mm screws being the safest option in 82% of shoulders 3
• Without CT planning, screws are frequently too long (mean 4.83 mm beyond posterior cortex for the inferior screw), increasing nerve injury risk 5
• The congruent-arc technique can reconstitute greater glenoid defects than the classic Latarjet orientation, but requires matching ROC between coracoid and glenoid 2