Optimization of bone-block positioning in the Bristow-Latarjet procedure: a biomechanical study

Area of Science:

• Orthopedic surgery
• Biomechanics
• Shoulder joint anatomy

Background:

• The Bristow-Latarjet procedure aims to stabilize the shoulder joint.
• Optimal positioning of the coracoid bone-block is debated.
• The effect of bone-block placement on humeral head stabilization needs biomechanical assessment.

Purpose of the Study:

• To biomechanically assess the impact of coracoid bone-block positioning on anterior and inferior humeral head stabilization.
• To compare the 'standing' versus 'lying' bone-block positions.
• To evaluate stabilization in different arm positions (ADER and ABER).

Main Methods:

• Eight fresh cadaveric shoulders underwent the Bristow-Latarjet procedure.
• Bone-blocks (2.5x1x1 cm) were placed in 'standing' and 'lying' positions at 3, 4, and 5 o'clock.
• Humeral head displacement was measured under traction in ADER and ABER positions.
• Radiological control was used to compare displacement with glenoid surface.

Main Results:

• The 'lying' bone-block position at 4 o'clock significantly reduced anterior and inferior humeral head displacement in ADER and ABER, respectively.
• In ABER, the 'lying' position also showed a trend towards decreased anterior translation, though not statistically significant.
• The 'standing' bone-block position did not influence humeral head translation.

Conclusions:

• Positioning the bone-block in a 'lying' manner at the 4 o'clock position (antero-inferior glenoid rim) enhances shoulder stabilization.
• This specific positioning effectively decreases anterior humeral head displacement (especially in ADER) and inferior glenohumeral translation (especially in ABER).
• The findings provide crucial biomechanical evidence for optimizing the Bristow-Latarjet procedure.