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

Introduction Intramedullary nail (IMN) fixation for proximal humerus fractures have 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 IMN for a proximal humerus fracture by one of three surgeons between the years of 2009-2022, and who had a minimum of 12-months follow-up. Fracture pattern, ASES score, SANE score, satisfaction, pain score, range of motion (ROM), and complications were recorded. The mechanism of injury (high energy versus low energy), method of reduction (open versus percutaneous), and evidence of radiographic healing were assessed. A p-value of < 0.05 was considered to be statistically significant. Results The study included 78 patients (62 female, 16 male). The number of patients in each group (2-part, N = 32 versus 3- or 4-part, N = 46), mean age (2-part, 64 versus 3- or 4-part,61), follow-up (2-part, 42.5 months versus 3- or 4-part,34.5 months), injury type (2-part, 88% low energy versus 3- or 4-part, 78% low energy), and method of reduction (2-part, 81% percutaneous versus 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 SANE 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 (p=0.414). The overall rate of conversion to arthroplasty was 3.2% in 2-part fractures and 10.4% in 3- or 4-part fractures. Conclusion Multipart proximal humerus fractures remain difficult to treat. However, this study demonstrates an overall acceptable outcome with improvement in ROM, patient-reported outcomes, and similar complication rates between 2-part versus 3- or 4-part proximal humerus fractures. However, the improvement in certain parameters is not as marked in 3- or 4-part fractures as 2-part fractures.