Clinical evaluation of a new custom offset shoulder prosthesis for treatment of complex fractures of the proximal humerus.

Primary hemiarthroplasty of the shoulder is an accepted procedure to treat complex proximal humeral fractures. The goal of this study was to assess the functional outcome in patients treated with hemiarthroplasty using a custom offset shoulder prosthesis, either for an acute four-part fracture of the proximal humerus or following failed primary treatment of a complex humeral fracture. Thirty seven patients were followed up for a mean of 17 months after shoulder replacement (Group A: four-part-fractures; n = 26, Group B: posttraumatic necrosis/non-union after failed primary treatment; n = 11). The Constant-Murley-Score and radiological score according to Neer's classification were used for postoperative functional and radiological assessment. Following hemiarthroplasty, Group A achieved an average Constant Score of 52 and Group B of 46. The pain relief after hemiarthroplasty was about 53% in Group A and only 33% in Group B. The least satisfying partial function was shoulder mobility in both groups. Radiographic evaluation did not correlate with the Constant Score. Patients secondarily treated with arthroplasty seem to have less chance to achieve a satisfying functional outcome compared to those with immediate hemiarthroplasty. These results emphasise the importance of a careful initial decision to select the most appropriate treatment modality in complex fractures of the proximal humerus.