Plate Osteosynthesis of Proximal Humerus Fracture is Associated with Significant Complications and Poor Functional Score for Patients Older than 45 Years Old: A Cohort Study.

Background: Despite the introduction of new implants and biomechanical improvements for proximal humerus fractures (PHF), the complication rate remains significant, particularly in older adults. This study aimed to identify risk factors for complications and failure following plate osteosynthesis for PHF and discuss an age cut-off that surgeons should consider for complications.

Methods: Adults with PHF treated with the proximal humerus internal locking system (PHILOS) at our large tertiary academic referral center between 2015 and 2020 were retrospectively identified. Univariate analysis was used to compare patients with and without complications. Then, a multivariate regression analysis was conducted to assess the possible complication risk factors. The receiver operating characteristic (ROC) curve of age was drawn to predict complication-free and favorable functional outcomes at the most recent follow-up. Oxford Shoulder Score (OSS) was considered favorable if OSS<10.

Results: A total of 135 patients were identified, with a mean age of 44 years (range 18-85 years) and a mean follow-up duration of 4.6 years (range 2-8 years). Complications were observed in 19 cases (14.1%), namely nonunion (n=5), avascular necrosis (n=1), infection (n=1), intra-articular screw perforation (n=1), arthritic changes (n=5), and superior humeral head migration (n=5). Eight patients (5.9%) needed revision surgery. Older age (OR=1.09) and Neer IV class (OR= 8.3) were associated with an increased likelihood of complication (P<0.001, P=0.02, respectively) in logistic multinominal regression analysis. The ROC curve for age in predicting complication-free cases had an area under the curve (AUC) of 0.829, indicating age as a significant predictor of ORIF outcomes in PHF (P<0.05). The optimalcut-off for age was 44 years, which yielded a sensitivity of 100% and a specificity of 65.7. The age ROC curve for predicting favorable OSS (OSS<10) had an of 0.829, indicating that age could predict the favorable OSS outcomes of ORIF in PHF. The optimal age cut-off was 46 years, yielding a sensitivity of 70.0% and a specificity of 78.6%.

Conclusion: The outcomes of ORIF for PHF in patients older than 45 years are associated with significantly higher complication rates and poorer functional outcomes. Surgeons should possibly consider other treatment options for PHF in each older patient individually, especially with Neer type IV fractures.