To determine the outcome after indirect reduction and buttress plate fixation of displaced and unstable proximal humeral fractures: we retrospectively evaluated 98 patients, an average of 34 months (range 24-72 months) after fracture fixation. The patients were reviewed and results were evaluated clinically according to the Neer, UCLA and Constant score. A radiographic evaluation of fracture healing, avascular necrosis and degenerative changes of the shoulder joint was performed in all patients. Any complications of treatment were assessed. Results were, according to the UCLA-rating system, good to excellent in 76% of fractures. According to the Constant-score and the Neer score, good to excellent results were obtained in 69 and 59% of fractures, respectively. Poor results were mainly due to secondary malunion. The avascular necrosis rate was 4%. Non-union was seen in one case. Secondary varus deformity and retroversion of the humeral head as a result of lack of rotational and angular stability of the plate developed in twelve (12%) and eight (8%) cases, respectively. Plate fixation is an adequate procedure for treating unstable and displaced two- to four-part fractures of the proximal humerus, enabling early functional after-treatment. The incidence of avascular necrosis and nonunion are low, when fracture reduction is performed indirectly. Poor rotational and angular instability can lead to a loss of reduction. (C) 1999 Elsevier Science Ltd. All rights reserved.