Fig. 1

a Intraoperative images show an ulna atrophic nonunion with bone loss and consequent gap; b both groups of patients were treated with the standard surgery procedure consisting of removing nonviable bone tissue and reopening the medullary canal; c fractures were stabilized with plates and screws according to the AO principles and a cortical homoplastic stick to increase stability; d lyophilized bone chips were used to fill the gap; e preparation and f application of biological adjuvants (PRF and BMAC) in all patients of group B