Background: The elbow stiffness is a common complication after operation of terrible triad injury (TTI) and significantly impair the patients’ activities of daily living, while the risk factors have yet to be clearly identified. The goal of this study was to examine the patient-related, injury-related, and treatment-related factors for elbow stiffness after operation of terrible triad injury.Methods: Between January 2013 and December 2019, 71 patients at two tertiary-care referral centers underwent operation of terrible triad injury were respectively reviewed. Range of motion (ROM), Mayo elbow performance scores (MEPS), Broberg-Morrey scores were used for functional evaluation. According to the ROM, the patients were categorized into stiffness group and non-stiffness group. The former had < 100° of extension-flexion ROM and the latter had > 100°. The patient-related, injury-related, and treatment-related factors were extracted from the medial records. The multivariant logistic regression were performed to identify the independent factors.Result: At a mean follow-up of 35.9 months (12-68 months),13 patients were classified into the stiffness group and 58 patients in the non-stiffness group. The stiffness group had significant worse functional scores compared to the non-stiffness group. Patients in the stiffness group were more likely to be Mason type III fracture, high-energy injuries, to have longer time between injury and surgery, ipsilateral upper limb injuries, and other fractures in body. However, multivariant logistic regression analysis revealed that time between injury and surgery > seven days, concurrent ipsilateral upper limb injuries and high-energy injury were independent factors that increased the risk of elbow stiffness after operation of terrible triad injury.Conclusions: The patients underwent operation for terrible triad injury should be informed the probability of elbow stiffness when concurred ipsilateral upper limb injuries and operations should be conducted without delay. Knowledge of these risk factors will be helpful for guiding prophylaxis and early intervention in patients with high risk of elbow stiffness after operation of terrible triad injury.