What information does the surgeon need before using software to plan a total shoulder arthroplasty? An international perspective.

Shoulder arthroplasty is a surgical procedure that is increasingly being used to treat patients with shoulder joint disorders, such as osteoarthritis and rotator cuff tears. Preoperative planning and the accurate transfer of this plan to the surgical procedure are critical for the success of the surgery. Three-dimensional (3D) preoperative planning software that assists with arthroplasty requires some basic surgical planning steps. These steps include segmentation of the bones, defining anatomic landmarks, 3D templating, and positioning of the planned implant. Surgical planning is thereby influenced by the surgeon's preferred implant and surgical technique, which is influenced by the bone and soft tissue pathology. Only the bone pathology is defined within the 3D preoperative planning software and in some software the premorbid patient-specific normal anatomy is defined. Each software utilizes its specific methods. These 3D preoperative planning software programs have generally been found to improve the accuracy of preoperative planning and the execution of implant positioning. However, it is important for shoulder surgeons to be aware that these systems are not all comparable, have their limitations and potential pitfalls, and therefore can potentially introduce errors into the surgical procedure.