Optimizing glenoid component position using three-dimensional computed tomography reconstruction

Glenoid implant design and alignment are critical to the success of shoulder arthroplasty. Computer-aided design models of 3 glenoid implant designs (keel, standard pegs, and modified pegs) were virtually implanted into 3-dimensional computed tomography-reconstructed models of 40 normal scapulae. The incidence of perforation on 3-dimensional computed tomography preoperative templating varied from 8% to 18% for the 3 models. Malalignment of the implants in retroversion was better tolerated than anteversion and varied with implant design. Tolerance for medialization of the implant to correct for glenoid wear was limited (range, 0 degrees-18 degrees) and varied with implant design. The modified peg design had the lowest incidence of perforation, the greatest tolerance for malalignment, and the ability to correct for glenoid wear effects. These results emphasize the need for accurate preoperative templating and for developing alignment guides or surgical navigation tools for shoulder arthroplasty and may be used to improve implant fixation designs.