AJSM Webinar Series: Management of Anterior Shoulder Instability: A Highlight of the Top 4 Articles in AJSM (2024 to 2025)-Provencher - Biomechanical Evaluation and Surface Analysis of Glenoid Reconstruction Using a Subtalar Joint Allograft

Provencher - Biomechanical Evaluation and Surface Analysis of Glenoid Reconstruction Using a Subtalar Joint Allograft

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This controlled laboratory study evaluated the biomechanical performance and surface characteristics of a novel subtalar joint allograft (STA) compared to the coracoid graft used in the Latarjet procedure and the established distal tibial allograft (DTA) for glenoid reconstruction in cases of significant glenoid bone loss (GBL) associated with recurrent anterior shoulder instability.<br /><br />Using eight fresh-frozen cadaveric shoulder specimens, researchers simulated a 30% anterior glenoid defect and tested five conditions: native intact glenoid, bone loss state, Latarjet procedure, DTA reconstruction, and STA reconstruction. Biomechanical tests applied 440 N compressive loads at varying abduction angles with pressure sensors capturing average contact pressure, peak contact pressure, and contact area. Surface geometry was analyzed using 3D laser scanning and custom software to assess surface area and congruency.<br /><br />Key findings include:<br /><br />- Both the DTA and STA reconstructions restored glenohumeral contact parameters—average contact pressure, peak contact pressure, and contact area—to levels comparable to the native glenoid at 60° abduction and 60° abduction with 90° external rotation, while the Latarjet procedure showed less favorable results.<br /><br />- Surface area was highest with DTA reconstruction, exceeding native levels; STA and Latarjet grafts showed physiological or slightly reduced surface area.<br /><br />- Surface congruency to the native glenoid was significantly better with DTA and STA compared to the Latarjet, with no significant difference between DTA and STA.<br /><br />- The Latarjet procedure yielded increased peak contact pressures and reduced contact areas, potentially due to poorer congruency and absence of cartilage, which may contribute to complications like arthropathy.<br /><br />The study supports that STA provides biomechanical contact mechanics and surface geometry comparable to the DTA and superior to the traditional Latarjet procedure, suggesting it as a promising anatomic, cartilage-preserving graft alternative. The STA may offer particular advantages in cases of bipolar bone loss requiring concurrent humeral head and glenoid reconstruction using a single graft source.<br /><br />Limitations include the cadaveric design lacking soft tissue and muscle forces, inability to simulate long-term remodeling, and use of a standardized bone defect that may not replicate clinical variability. Further clinical investigations are needed to assess in vivo outcomes, graft incorporation, and long-term stability.<br /><br />In conclusion, the STA represents a novel, potentially effective allograft for anatomic glenoid reconstruction, warranting future clinical study alongside established graft options like the DTA.

Keywords

subtalar joint allograft

STA

distal tibial allograft

DTA

Latarjet procedure

glenoid reconstruction

glenoid bone loss

biomechanical performance

shoulder instability

cadaveric study