What is the incidence of total elbow arthroplasty after intra-articular versus extra-articular distal humerus open reduction and internal fixation?

Introduction: Distal humerus fractures are rare but technically challenging. Intra-articular patterns may predispose patients to post-traumatic osteoarthritis, potentially requiring total elbow arthroplasty (TEA). This study compared TEA incidence after intra- versus extra-articular distal humerus fracture fixation across age groups. Methods: The TriNetX database (2006–2026) was queried for patients undergoing open reduction and internal fixation (ORIF) of distal humerus fractures. Patients were stratified into younger (10–40 years) and older (>50 years) cohorts and classified as extra-articular (current procedural terminology (CPT) 24545) or intra-articular (CPT 24546, 24586, 24579). Cohorts were 1:1 propensity-matched for demographics and comorbidities. Younger patients were analyzed as a combined cohort. Kaplan–Meier analysis estimated TEA incidence at 1, 3, 5, and 10 years. Results: In the older cohort (2181 patients/group; mean age ∼70 years), intra-articular fractures demonstrated significantly higher TEA conversion at 1 year (3.9% vs. 1.6%), 3 years (4.3% vs. 2.1%), 5 years (4.3% vs. 2.1%), and 10 years (4.4% vs. 2.2%) (all ps < 0.05; odds ratio: 2.02–2.46). Kaplan–Meier analysis confirmed lower TEA-free survival in intra-articular patients (p < 0.001). TEA conversion remained rare in younger patients (1.04% at 10 years). Conclusion: TEA conversion after distal humerus ORIF is uncommon overall but varies by age and fracture pattern, supporting individualized counseling. Level of evidence: Level III, Prognostic.