The effects of coronoid fracture fixation on functional outcomes and complication rates following terrible triad injuries of the elbow

Background: Management of the coronoid fracture in terrible triad injuries (TTI) of the elbow remains controversial. We compared outcomes of TTI patients with versus without coronoid fixation.Methods: We retrospectively analyzed 105 TTI patients; 59 patients with no fixation (group 1) and 46 patients with coronoid fixation (group 2). Complications, revisions, range of motion (ROM) and functional scores (Mayo Elbow Performance Score [MEPS], Quick Disabilities of the Arm, Shoulder and Hand [QuickDASH], Subjective Elbow Score [SES]) were assessed. Stratified analyses using t-tests and Fisher's exact tests with Cohen’s d were performed according to O’Driscoll (OD) subtype (type 1 tip, type 2 anteromedial facet, and type 3 basal).Results: Baseline OD distribution differed substantially between groups 1 and 2 (type 1: 79.7% vs. 34.8%, respectively; type 2: 18.6% vs. 58.7%, respectively; P<0.001). Follow-up timing was comparable between the two groups (first, 4.4 vs. 4.1 months; final, 3.0 vs. 2.8 years). In the whole cohort, group 2 patients showed greater flexion (P=0.030), pronation and supination (both P<0.001), and better MEPS (P=0.032), QuickDASH (P=0.027) and SES (P=0.044) than group 1 patients. Stiffness (22.0% vs. 2.2%, P=0.003) and revision surgery rates (30.5% vs. 10.9%, P=0.018) were significantly higher in group 1 than in group 2. Within OD type 2, fixation was associated with significantly greater flexion (P=0.001), pronation (P=0.005), and supination (P<0.001), and lower rates of nonunion (9% vs. 50%, P=0.046) and posttraumatic osteoarthritis (5% vs. 50%, P=0.025) than non-fixation.Conclusions: OD type 2 fractures repaired with coronoid fixation showed greater ROM and lower complication rates than these types of fractures repaired without coronoid fixation. Within OD type 1, coronoid fixation did not show any significant benefits compared to no fixation.Level of evidence: III, retrospective cohort study.