Background: Management of comminuted radial fractures remains controversial. Currently, the emergence of on-table reconstruction technique has made fixation in comminuted radial head fractures more viable. However, the present study reported an intro-operative unstable displacement from the reconstructed radial head to the neck during plate fixation, characterized by a poor radiocapitellar contact and incongruity between the radial head and neck. A hybrid technique combining with intramedullary pining was performed in our study to restore the normal alignment and maintain the stability of fixation. Therefore, the purpose of this article aimed to prove the feasibility of unstable comminuted radial head fractures treated with the extramedullary plate and intramedullary pinning fixation using titanium elastic nails. Methods: The clinical, functional and radiographic outcomes of the groups were compared during follow-up. The radiographic examination was conducted to evaluate the status of bone union, heterotopic ossification and post-traumatic arthritis. The functional assessment was performed to evaluate clinical effects, which included measurements of range of motion (ROM) in the elbow, Visual Analog Scale (VAS) score, Elbow Self-Assessment score (ESAS), Mayo Elbow Performance score (MEPS), and Disabilities of the Arm, Shoulder, and Hand (DASH)Outcome Measure score.Results: Fifteen patients with unstable fractures were participated with an average follow-up of (37.2±5.8) months for the experimental group and (33.2±7.1) months for the control group, respectively. The ROM of the elbow and functional outcomes in the experimental group, including MEPS and DASH, were significantly superior to the control group. However, no significant difference was observed in the mean VAS score between two groups. In the last follow-up, two patients with post-traumatic arthritis rated as grades 1 and two with heterotopic ossifications were observed in the experimental group. In the control group, degenerative changes were observed in four cases (grade 1 in three cases and grade 2 in one case) and heterotopic ossifications rated as grade I were found in two patients. Conclusion: Collectively, intramedullary pinning with extramedullary plate fixation is feasible in unstable comminuted radial head fractures, which can be considered as a remedial surgery for on-table reconstruction technique. Trial registration: This study was retrospectively registered