So far, glenoid implantation still remains a challenge and is technically demanding even for an experienced shoulder surgeon. Each shoulder pathology has its own evolution. In primary glenohumeral osteoarthritis, glenoid involvement and proper morphology vary considerably. Erosion is more posterior and inferior. In rheumatoid arthritis, glenoid erosion is more medial with a very weak and soft bone. In eccentric arthritis, glenoid erosion is most of the time superior. Glenoid component loosening has been recognized as one of the common indications for revision surgery after total shoulder arthroplasty. Scapular notching is specific to the reverse shoulder arthroplasty. Moreover, there is concern about the high frequency of glenoid components that demonstrate radiographic periprosthetic lucencies. There is little information available to guide clinical decision making regarding glenoid surgery. Placement or replacement with a standard glenoid component is usually possible. In some instances, bone graft reconstruction or the use of augmented or custom components can be an option. The purpose of this study is to evaluate the main glenoid erosion classifications.