Background: Our study aimed to evaluate the clinical and radiologic results of all-arthroscopic treatment of terrible triad injuries followed-up for a minimum of 5 years and investigate how arthroscopic partial excision for radial head fractures affects the results at the final follow-up.Methods: We retrospectively reviewed consecutive patients with terrible triad injuries who underwent all-arthroscopic treatment between January 2011 and June 2018. In group I, we performed conservative or arthroscopic fixation of stable radial head fractures, while in group II, arthroscopic partial excision of unstable radial head fractures involving <30%–50% of the articular surface area was performed. Clinical outcomes were measured by visual analog scale score and assessment of instability, range of motion (ROM), and Mayo Elbow Performance Score. Radiological outcomes were evaluated using x-rays, and the integrity of the repaired lateral collateral ligament complex was confirmed through magnetic resonance imaging.Results: Thirty-two patients with an average age of 49.5±16.2 years met the inclusion criteria and were followed-up for a mean of 82.7±22.2 months. Twenty patients were assigned to group I and 12 patients to group II. Clinical outcomes showed no significant differences between the two groups at the final follow-up (P>0.05). On radiological evaluation, more heterotopic ossifications were found in the radial head excision group (group II, 66.7% versus group I, 35%, P=0.02); however, there was no significant difference in ROM between the two groups (P>0.05).Conclusions: In all-arthroscopic treatment of terrible triad injuries, arthroscopic partial excision of the radial head did not seem to have a significant impact on elbow joint stability.Level of evidence: III.