Epiphyseal fragment as a predictive factor of failure in fixation of proximal fractures of the humerus

•There are several possible causes of failure in fixation after a surgical treatment.•We found a correlation between the size of the epiphyseal fragment in fractures of the proximal humerus and surgical failure.•A cross-sectional length of the epiphyseal fragment of less than 15.5 mm indicates a higher probability of loss of reduction after osteosynthesis. Fractures of the proximal humerus are frequent and are widely studied with regards to their treatment indications. The aim of this article is to establish a correlation between the size of the epiphyseal fragment in fractures of the proximal humerus and the probability of loss of reduction after a surgical procedure. A total of 47 surgically treated proximal humeral fractures were reviewed. Preoperative CT scans were used to evaluate the size of the epiphyseal fragment of the fracture. Postoperative X-rays were analyzed to assess complications, especially loss of reductions. Mean age was 61 years old (29–91 years). In total, 42 shoulders were evaluated. The average size of the epiphyseal fragment was 38.3 mm (32–50 mm) the largest longitudinal length; and 19.9 mm (12–30 mm) the largest cross-sectional length. The most frequent complication observed was loss of reduction. The statistical analysis showed significance that patients with smaller cross-sectional size of the epiphyseal fragment presented more complications (p = 0.034), and based on the graph and ROC curve, a value of 15.5 mm was considered as the cutoff value for failure. A cross-sectional length of the epiphyseal fragment of less than 15.5 mm indicates a higher probability of loss of reduction in fractures of the proximal end of the humerus after extra-medullary osteosynthesis.