Problem of and solution for uneven wear and erosion of glenoid. A, Area of wear. B, If glenoid component is inserted without correction of slope, anchoring device passes out of medullary canal; tilt and loss of height also make implant unstable. C and D, Severe erosion is corrected by bone grafting. Piece of humeral head is secured to scapula with 4-mm AO navicular screw. Lesser erosion can be offset by building up low side with acrylic cement or lowering high side. Building up with cement is not recommended because of feared cement loosening. Lowering high side often requires shortening holding device of glenoid component and creates laxity between components, which can make implant temporarily unstable and requires special postoperative care. Alternatively, an augmented glenoid component can be used to correct glenoid version. SEE TECHNIQUE 12.2.