Abstract
BACKGROUND: Assessment and quantification of bone loss in cases of shoulder instability is critical for surgical decision making. The glenoid track concept was initially developed to assess Hill Sachs lesions taking into account the native glenoid diameter of the contralateral shoulder and assessing the degree of glenoid bone loss. However, it can not be reverse calculated to determine the effect of an addition of a bone block. We have developed a novel model to help address this problem yielding an "effective glenoid track" (EGT). METHODS: Begin as we always do by using Itoi's concept for assessment of tracking based on the CT scan cuts. Next step is to calucate the Hill Sach's interval (HSI) which will require an MRI scan. CONCLUSION: The EGT allows for calculation of residual tracking of Hill Sachs lesions post a bone block addition and will aid in surgical decision making.