Assessment of Primary Stability and Micromotion of Different Fixation Techniques for Scapular Spine Bone Blocks for the Reconstruction of Critical Bone Loss of the Anterior Glenoid—A Biomechanical Study

Anteroinferior shoulder dislocations require surgical intervention when related to critical glenoid bone loss. Scapular spine bone blocks have emerged as a promising alternative to traditional bone augmentation techniques. However, limited data exist on their biomechanical stability when using different suture-based fixation techniques. This study aimed to evaluate primary stability and micromotion after glenoid augmentation using a scapular spine bone block. A total of 31 fresh-frozen human shoulder specimens underwent bone block augmentation. The specimens were randomized into three groups: double-screw fixation (DSF), single-suture bone block cerclage (SSBBC), and double-suture bone block cerclage (DSBBC). Biomechanical testing was conducted using cyclic loading (5000 cycles at 1 Hz) and micromotion was analyzed using an optical 3D measurement system. Statistical analysis showed that medial irreversible displacement was significantly greater in the SSBBC group compared to DSF (<i>p</i> = 0.0386), and no significant differences were found in anterior or inferior irreversible displacements. A significant difference was noted in posterior reversible displacement (<i>p</i> = 0.0035), while no differences were found in inferior or medial reversible displacements. Between DSF and DSBBC, no significant differences were found in irreversible or reversible displacements in any direction. DSBBC provided stability comparable to DSF while offering a viable metal-free alternative. In contrast, SSBBC displayed inferior biomechanical properties, raising concerns about its clinical reliability.