OBJECTIVES: To examine the impact of preoperative coronal plane deformity on functional and radiographic outcomes on endosteal strut augmentation of proximal humerus fracture fixation. DESIGN: Single surgeon, retrospective analysis of a prospective database. Case series. SETTING: Academic level 1 trauma center. PATIENTS/PARTICIPANTS: Seventy-two patients with isolated proximal humerus fractures fulfilled all inclusion/exclusion criteria with a minimum follow-up of 12 months. INTERVENTION: Proximal humerus open reduction internal fixation with a laterally placed proximal humeral locking plate and endosteal placement of an allograft fibula treated through the anterolateral approach. MAIN OUTCOME MEASUREMENTS: Global functional outcome as determined by the Disabilities of the Arm, Shoulder and Hand (DASH) score and Short Form 36 physical function. Shoulder-specific functional outcome as determined by the Constant-Murley and the University of California Los Angeles shoulder scores. RESULTS: The mean age was 62 years old (range, 26-90 years). There were 32 varus fractures (neck-shaft angle, 110.8 degrees) and 40 valgus fractures (neck-shaft angle, 168.9 degrees). There was no significant difference in the initial postoperative (varus: 132.5 degrees, valgus: 135.5 degrees) and final (varus: 129.9 degrees, valgus: 132.2 degrees) neck-shaft angles or change in humeral height (varus: 0.94 mm, valgus: 1.48 mm). There were no significant differences in functional outcomes [Constant (varus: 85.2, valgus: 88.7) DASH (varus: 21.4, valgus: 13.9), University of California Los Angeles (28.6, varus 30.4), and Short Form 36 (varus: 66.8, valgus: 59.1)]. There were 2 patients in the valgus group and 3 patients in the varus group with an asymptomatic humeral head screw penetration (mean Constant 84.5, DASH 9.5). There was 1 deep infection in the varus group and 2 in the valgus group necessitating implant removal after fracture union. There was 1 case of avascular necrosis in the valgus group (DASH 19.4, Constant 73). CONCLUSIONS: There were no significant differences in complication rates, radiographic, or clinical outcomes between fractures presenting with preoperative varus coronal displacement compared with those presenting with valgus coronal displacement. The equivalent outcomes may be attributed to the uniform operative technique and fibular strut augmentation used by the primary surgeon. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.