AJSM Webinar Series: Management of Anterior Shoulder Instability: A Highlight of the Top 4 Articles in AJSM (2024 to 2025) - Recording-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

Pdf Summary

This controlled laboratory cadaveric study evaluated biomechanical properties and surface characteristics of glenoid reconstruction using a novel subtalar joint allograft (STA) compared to the traditional Latarjet coracoid graft and distal tibial allograft (DTA) for significant glenoid bone loss (GBL) associated with recurrent shoulder instability. Eight fresh-frozen cadaveric shoulders underwent testing in five conditions: native intact, 30% anterior glenoid bone defect, Latarjet procedure, DTA reconstruction, and STA reconstruction. Compressive loads were applied at 30° abduction, 60° abduction, and 60° abduction with 90° external rotation (ER), with measurement of contact pressure, peak contact pressure, contact area, surface area, and surface congruency.<br /><br />Key findings include that both DTA and STA reconstruction restored average and peak contact pressures and contact area to native levels at 60° abduction and 60° abduction with 90° ER, unlike the Latarjet procedure which showed increased peak contact pressure and reduced contact area, especially at lower abduction angles. The DTA yielded the largest glenoid surface area, exceeding native levels, while STA and Latarjet showed physiological surface areas. Surface congruency with native glenoid anatomy was superior with both DTA and STA compared to the Latarjet procedure. The STA demonstrated biomechanical performance and surface geometry comparable to the DTA.<br /><br />The study suggests that anatomic glenoid reconstruction with osteochondral allografts like STA or DTA better restore joint biomechanics and cartilage congruency compared to the nonanatomic Latarjet coracoid graft, which lacks a cartilaginous surface and can lead to complications such as graft osteolysis and altered joint mechanics. The STA’s similar radius of curvature to the glenoid and DTA, along with its potential to simultaneously address bipolar bone loss (glenoid and humeral head), highlights its promise as a novel alternative graft source.<br /><br />Limitations include the cadaveric model (absence of soft tissue and muscle loading), simplified graft preparation, and no long-term in vivo data. Further clinical studies are needed to validate STA’s safety, efficacy, and outcomes in patients. Overall, the STA offers a promising anatomic reconstruction option that might overcome limitations of current grafts in managing severe glenoid bone loss in shoulder instability.

Keywords

glenoid reconstruction

subtalar joint allograft

STA

Latarjet procedure

distal tibial allograft

DTA

glenoid bone loss

shoulder instability

biomechanical properties

cartilage congruency