Eccentric reaming is superior to augmented components in B2 glenoids: a biomechanical study.

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Biomaterials Science

Background:

• Primary glenohumeral arthritis often involves glenoid retroversion and posterior bone loss.
• Glenoid component fixation is critical for anatomical total shoulder arthroplasty (aTSA) survivorship, especially in B2 glenoids.
• This study evaluates glenoid preparation techniques for B2 glenoid bone loss models.

Purpose of the Study:

• To compare the biomechanical stability of two glenoid preparation techniques in a simulated B2 glenoid bone loss model.
• To assess the effect of different correction angles and component augmentations on glenoid fixation.
• To determine the optimal surgical approach for improving glenoid component stability in revision shoulder arthroplasty.

Main Methods:

• A biomechanical cyclic loading study using 30 sawbone models of a scapula with a B2 glenoid and 15° retroversion.
• Groups included eccentric reaming (7° and 12°) with standard components and augmented components (7° and 12° correction).
• Cyclic loading to 100,000 cycles assessed component displacement and loosening to compare fixation stability.

Main Results:

• All 26 analyzed samples reached 100,000 cycles, with significant displacement increase from baseline in all groups.
• The 12° anterior reaming group (B1) showed significantly less displacement (1.4 mm) than augmented groups (A2: 2.0 mm, B2: 2.2 mm) at 100,000 cycles.
• No significant differences in translational forces were observed between groups at 100,000 cycles.

Conclusions:

• Higher degree posteriorly augmented glenoid components led to greater translational displacement over time compared to high-side reaming.
• Anterior reaming with a standard component may provide superior glenoid fixation in B2 glenoid bone loss models.
• Further clinical studies are necessary to validate these biomechanical findings for anatomical total shoulder arthroplasty outcomes.