Background <p>Heterotopic ossification (HO) is a frequent complication after surgical management of distal humerus fractures. This study aimed to identify factors associated with HO formation following fixation of AO/OTA type C distal humerus fractures, with particular attention to the potential influence of the olecranon osteotomy approach.</p> Methods <p>We retrospectively analyzed 57 patients who underwent open reduction and internal fixation for intra-articular distal humerus fractures (AO/OTA 13C1–C3) between 2015 and 2024. Patients treated with either olecranon osteotomy or paratricipital approaches were included. Demographic, clinical, and radiological data were collected, and HO was graded using the Hastings and Graham classification at six months postoperatively. Statistical analyses were conducted to identify independent risk factors for HO.</p> Results <p>HO was observed in 31 patients (54.4%). HO was significantly associated with the surgical delay of ≥ 6 days (OR = 4.94; <i>p</i> = 0.005), and AO/OTA type C3 fractures (31.6%) (OR = 5.11; <i>p</i> = 0.008). The use of olecranon osteotomy (31.6%) initially appeared to increase the risk of heterotopic ossification (OR = 4.13; <i>p</i> = 0.020) in univariate analysis; however, this significance diminished after adjustment for confounding factors in the multivariate analysis (OR = 2.97; <i>p</i> = 0.123). Age, surgical duration, intraoperative blood loss, and trauma energy did not show significant association with HO. The incidence of higher-grade HO (≥ 2) (67.7%) was also more frequent in patients with these risk factors.</p> Conclusion <p>Olecranon osteotomy, delayed surgery, and AO/OTA type C3 fracture patterns are independent risk factors for HO development following distal humerus fracture surgery. Surgeons should consider early intervention and triceps-sparing approaches to minimize HO risk, particularly in complex fractures.</p> Trial registration <p>Not applicable. This study is a retrospective study with ethics committee approval.</p>