Technique and clinical results of a new intramedullary support nail and plate system for fixation of 3- or 4- part proximal humeral fractures in older adults

Background: Internal fixation of complex proximal humeral fractures (PHF) with osteoporosis is associated with a high incidence of complications. This study introduces the technique and clinical results of a novel intramedullary support nail and plate system (ISNPs) for the internal fixation of 3- or 4- part PHF in older adults. The ISNPs combines the concept of intramedullary support and dynamic fixation into a locking plate fixation system that can be applied using a minimally invasive surgical approach.Methods: A total of 46 consecutive patients diagnosed with 3- or 4-part PHF that met the criteria were included in this study, including 18 in the ISNPs group and 28 in the conventional locking plate (LP) group. Clinical results, including operative time, intraoperative bleeding, reduction quality, subjective outcome ratings, and complications, were compared between the two groups. Functional outcomes were evaluated using the Constant score and disability of the arm, shoulder, and hand (DASH) questionnaire at 1-year follow-up.Results: There were no significant differences in age, sex, local bone quality, Neer-fracture type, and follow-up time between the ISNPs and LP groups. For clinical analysis, there were no significant differences in intraoperative bleeding and operation time between the ISNPs and LP groups. Significant differences were observed in the percentage of the malreduced cases, Constant and DASH score analysis, and “excellent” and “good” ratings between the two groups. Conclusion: The ISNPs technique proposed in this study provides a novel hybrid internal fixation model for complex PHF with osteoporosis. The clinical results at 1-year follow-up confirmed the advantage of applying it to 3- or 4- part PHF in older patients. Further studies are required to optimize its design and explore its optimal indications.