Proximal humerus fractures treatment in adult patients with bone metastasis.

The humerus is the second long bone most affected by pathological fractures. According to Capanna and Campanacci criteria, surgical choice is based on bone metastasis location, on the patient's status and on the residual functional capacity. Metadiaphysis is an area of conflict in the choice between megaprosthesis implant and intramedullary nail osteosynthesis. This study compares these two surgical procedures in terms of reacquired functionality and local control of metastasis. Thirty-eight patients (17 males and 21 females; mean age: 66 years old) treated in our institution between January 2010 and December 2020 for pathological humeral metadiaphyseal fractures caused by metastasis, were included in this study. We choose the Musculoskeletal Tumor Society rating system (MSTS) and the Quick Disability of Arm-Shoulder-Hand (QuickDASH) scores for the evaluation of the upper limb function after surgery. Eighteen (47%) pathological fractures were treated by resection and megaprosthesis implantation, twenty (53%) were treated by medullary nail osteosynthesis. A reduction in pain and greater mechanical stability in the immediate post-operative period was found in all patients. Twenty-two patients died (58%) and sixteen survived (42%). Long-term functional recovery of patients undergoing osteosynthesis is greater than megaprothesis group. Both medullary nail osteosynthesis and resection and megaprosthesis implantation guarantee excellent recovery at 72 months after surgery, improvement in quality of life and pain relief.  Patients treated with osteosynthesis showed a great short-term functional recovery since the joint portion of the limb is not involved, whereas patients treated with megaprosthesis showed better local oncologic control. It is therefore possible to define the type of treatment not only on the localization of the fracture (diaphysis or epiphysis) but above all on the conditions and characteristics of the patient.