Primary fracture arthroplasty of the proximal humerus using a new and freely adjustable modular prosthesis combined with compression osteosynthesis of the tuberosities

Abstract

Prosthetic joint replacement in case of non-reconstructable proximal humerus fracture in order to obtain a pain-free shoulder and an acceptable range of motion. The non-reconstructable proximal humerus fracture in aged, frail patients (over 70 years of age or ASA 3). Patient inoperable or rehabilitation is inacceptable, pre-existing infection of the shoulder, coexisting bacteremia, or rotator cuff insufficiency. Using a deltopectoral or deltoid split approach, the head fragment is removed. After reaming of the humeral canal, a stem is cemented in place. The Affinis Fracture prosthesis consists of three parts: the stem (3 sizes), a metaphyseal part (2 sizes), and a ceramic head (3 sizes). The retroversion of the metaphyseal part is freely adjustable (360°) after cementing the stem. The length can be adjusted over 1 cm. After reconstruction of the height and retroversion, the tuberosities are reattached anatomically. Finally, a compression osteosynthesis of the tuberosities is realized, using a metal cable, compressing the tuberosities directly upon the metaphyseal part. As the stability of this construct is very high, early postoperative mobilization is allowed. In order to avoid adhesion, rehabilitation exercises are started the day after surgery. During the first few days, passive mobilization, within pain limits, is performed. As soon as possible, active assisted mobilization is started. No stretching is performed, especially in rotation, before the sixth postoperative week. The arm is supported in a sling, only for analgesic reasons. Using this technique, anatomical healed tuberosities were obtained in 84% of the 44 patients with a mean Constant score of 59 points.