Detection of primary screw perforation in locking plate osteosynthesis of proximal humerus fracture by intra-operative 3D fluoroscopy.

Abstract

The purpose of this study was to identify the rate of primary screw perforations after osteosynthesis of proximal humerus fractures with intra-operative 3D fluoroscopy and to analyse the rate of secondary screw perforations as well as complications, outcome, and revision surgeries after a minimum of 12months. Thirty-three patients (20 female, 13 male, median age 67years, range 35-85years) with displaced proximal humerus fractures were included. After reduction and fixation, an intra-operative 3D fluoroscopy was performed to evaluate primary screw perforations (PS) and screws with "near perforation" (nPS). These screws were changed intra-operatively. Patients were followed-up for a minimum of 12months. Clinical and radiological parameters, such as secondary screw perforation, secondary loss of reduction, or functional outcome, were investigated. In six patients (18.2%), humeral head screws were changed due to primary PS (n=2) or nPS (n=4) after the intra-operative 3D fluoroscopy. Follow-up revealed an adapted constant score (%CMS) of 76.2% after a mean follow-up of 17.7months. Two secondary screw perforations were observed (6%). Loss of reduction was observed in eight patients (24.2%). The intra-operative 3D reveals a high rate of primary screw perforations or near perforations. Immediate change of these screws may lead to a lower rate of secondary screw perforations and, therefore, reduce post-operative complications.