Francesco Lazzarini - Department of Orthopaedic Surgery, Santa Maria Annunziata Hospital, Florence, Italy
Marco Distefano - Department of Orthopaedic Surgery, Santa Maria Annunziata Hospital, Florence, Italy
Tony Shen - Adult Reconstruction and joint Replacement, Hospital of Special Surgery, New York, NY, USA
Gregorio Secci - Department of Shoulder Surgery, AOU Careggi, University Hospital of Florence, Florence, Italy
Michael Cresci - Department of Shoulder Surgery, AOU Careggi, University Hospital of Florence, Florence, Italy
Raffaele Tucci - Department of Shoulder Surgery, AOU Careggi, University Hospital of Florence, Florence, Italy
Luigi Zanna - Department of Orthopaedic Surgery, Santa Maria Annunziata Hospital, Florence, Italy

Objectives: Proximal humerus fractures account for four-five % of all fractures. Shoulder hemiarthroplasty is indicated for complex fractures with high complication rates when treated with ORIF. This study aims to evaluate the correlation between the proper intraoperative tuberosity reduction, and the mid-to-long-term clinical outcome in a series of patients treated with hemiarthroplasty after proximal humerus fracture.Methods: Forty-one patients with proximal humerus fractures who underwent hemiarthroplasty surgery between July ۲۰۰۹ and December ۲۰۱۹ were retrospectively reviewed. Quantitative analysis of the reduction of the tuberosities was performed on postoperative X-rays focusing on the distance between reconstructed greater tuberosity and the apex of the head of the prosthesis, (head-tuberosity distance), and contact between tuberosity and humerus diaphysis. The University of California Los Angeles Score (UCLA) was calculated for each patient.Results: The mean time to surgery was ۶.۲۹ ± ۲.۸ days (range ۲-۱۸ days). Nine patients out of ۴۱ (۲۲%) had non anatomic tuberosity, and ۳۲ (۷۸%) were anatomic reduced. The UCLA score at the final follow-up was good and excellent (≥۲۷) in ۲۷ patients (۶۶%), and poor (<۲۷) in ۱۴ (۳۴%). A significant correlation was observed between proper tuberosity reduction and good/excellent UCLA scores (P<۰.۰۰۱).Conclusion: Hemiarthroplasty is a valid and reliable technique for the treatment of proximal humerus fracture not eligible for internal fixation, with high risk of failure. The proper tuberosity reconstruction, paying special attention to the HTD and the contact between the cortical of the humeral diaphysis and the reconstructed tuberosity, is essential to reach a good clinical outcome. Level of evidence: IV

clinical outcome, Hemiarthroplasty, Proximal humerus fractures, shoulder, Tuberosities reduction