Mathematical modeling of glenoid bone loss demonstrate differences in calculations that May affect surgical decision making

OBJECTIVE: Two glenoid bone loss calculations are compared across a range of anatomic glenoid sizes. METHODS: 20 cadaveric paired glenoid diameters were measured to create glenoid models with bone loss calculated in 1 mm linear increments up to 50% bone loss comparing the linear measurement percentage (LMP) to the circle line method (CLM) gold standard. RESULTS: The LMP overestimates glenoid bone loss at every potential 1 mm increment across each glenoid model until bone loss reaches 50%. CONCLUSION: The widely-used LMP method overestimates bone loss compared to a gold standard potentially misguiding surgeons towards bony reconstruction in shoulder instability during preoperative planning.