Replicating proximal humeral articular geometry with a third-generation implant: a radiographic study in cadaveric shoulders.

Prosthetic shoulder arthroplasty must replicate humeral geometry or risk compromising success. The purpose of our study was to evaluate humeral head replacement with respect to replicating proximal humeral anatomy. Using scanning technology and AutoCAD, this study was conducted in 2 parts. First, geometric parameters were measured on 35 cadaveric humeri and were used to design a new shoulder arthroplasty system. Second, humeral head replacement was performed on 18 of these humeri by use of the new shoulder arthroplasty system, and selected preoperative and postoperative measurements were compared. Preoperative to postoperative differences were minimal and exhibited improvement compared with earlier designs. In this study, humeral head replacement with a third-generation system reproduced the original anatomy of 18 cadaveric humeri more accurately than previously reported. This finding is important because accurate anatomic reconstruction in shoulders is essential for minimizing subacromial contact and optimizing range of motion.