Comparison of clinical outcomes and complications in 2-part vs. 3- or 4-part proximal humerus fractures treated using an intramedullary nail designed to capture the tuberosities.

Background: Intramedullary nail fixation for proximal humerus fractures has been shown to provide satisfactory results. The quality of reduction correlates with clinical outcomes, the rate of complications, avascular necrosis, and postoperative loss of fixation. The purpose of this study was to evaluate the clinical outcomes and complications of 2-part proximal humerus fractures compared to 3- or 4-part proximal humerus fractures. Methods: A single-center retrospective review was carried out of patients who underwent an intramedullary nail for a proximal humerus fracture by one of three surgeons between the years of 2009 and 2022, and who had a minimum of 12-months follow-up. Fracture pattern, American Shoulder and Elbow Surgeons score, Single Assessment Numeric Evaluation score, satisfaction, pain score, range of motion, and complications were recorded. The mechanism of injury (high energy vs. low energy), method of reduction (open vs. percutaneous), and evidence of radiographic healing were assessed. A Results: The study included 78 patients (62 female, 16 male). The number of patients in each group (2-part, N = 32 vs. 3- or 4-part, N = 46), mean age (2-part, 64 vs. 3- or 4-part,61), follow-up (2-part, 42.5 months vs. 3- or 4-part, 34.5 months), injury type (2-part, 88% low energy vs. 3- or 4-part, 78% low energy), and method of reduction (2-part, 81% percutaneous vs. 3- or 4-part 72% percutaneous) were similar among the two groups. There was fracture union in all patients. All patients demonstrated satisfactory patient-reported outcome measures. However, 2-part fractures did have a significantly lower pain score, higher Single Assessment Numeric Evaluation score, and higher percentage of patients being satisfied or very satisfied when compared to 3- or 4-part fractures. The rate of subsequent procedures was 13% (n = 4) in 2-part fractures compared to 19% (n = 9) in 3- or 4-part fractures but was not statistically significant ( Conclusion: Multipart proximal humerus fractures remain difficult to treat. However, this study demonstrates an overall acceptable outcome with improvement in range of motion, patient-reported outcomes, and similar complication rates between 2-part and 3- or 4-part proximal humerus fractures treated with an intramedullary nail. However, the improvement in certain parameters is not as marked in 3- or 4-part fractures as 2-part fractures.