Prognostic factors in prosthetic replacement for acute proximal humerus fractures

Objectives: To investigate the effect of some epidemiological and radiologic factors on the outcome of prosthetic replacement in acute proximal humerus fractures. Design: Retrospective clinical study. Patients: Thirty-two patients [mean age 58 (range 37-83 years)] with a mean follow-up period of 35 months (range 8-80 months). Fifteen cases had Neer type IV, 2 had type III, and 15 patients had fracture-dislocations. Main Outcome Measurements: Neer's criteria, Constant score, and elevation degree were used. Radiological parameters were union and position of the tuberosities, bone stock, and position of the prosthesis. Results: Excellent or good results according to Neer's criteria were obtained in 24 of the 32 cases (75%), and unsatisfactory results in 8 cases (25%). Mean Constant score was 68 (range 19-98) and mean elevation degree 113 (range 30-180). Thirty-one cases (97%) had no or mild pain. Cases operated within 14 days following injury had a better general outcome (p = 0.005). The humeral offset was directly correlated to the elevation degree (p = 0.011) and Constant score (p = 0.002), whereas the head height was inversely correlated to the same parameters (p = 0.001 for both). The cutoff point for the humeral offset-general outcome correlation was calculated as 23 mm using ROC curve analysis. The most common complications were problems concerning the tuberosities (50%), and they adversely affected the clinical outcome (p = 0.002). Conclusions: Preoperative delay, problems of tuberosity fixation, and position of the tuberosities were parameters influencing the clinical outcome. Lateralization of the tuberosities results in better scores, whereas their distal transfer can be related to a poorer outcome.