Background The treatment of complex persistent elbow instability after trauma is challenging. Previous studies on treatments have reported varied surgical techniques, which makes it difficult to establish a therapeutic algorithm. Furthermore, the surgical procedures may not sufficiently restore elbow stability, even with an additional device, and a noted high rate of arthritis progression.While a recently developed internal joint stabilizer effectively treats elbow instability, its clinical application for complex persistent elbow instability is limited and the standardized protocol is not well described. Additionally, we want to know whether the arthritis progression will cause a negative impact on the functional outcomes of complex persistent elbow instability. Questions/purposes (1) Does treatment of complex persistent elbow instability with a hinged internal joint stabilizer and a standardized protocol prevent recurrent instability and other complications? (2) What are the pre-to postoperative improvements in pain, disability, elbow performance, and ROM? (3) Is the development of posttraumatic arthritis associated with worse pain, disability, elbow performance, and ROM? Methods Between September 2014 and October 2019, we treated 22 patients for persistent dislocation or subluxation after initial treatment of traumatic elbow fracturedislocations. Of those, we considered patients who were at least 20 years of age, with an interval of 6 weeks or more between the injury (initial treatment) and the index reconstructive procedure, which had been performed at our institute, as potentially eligible. During that time, we used an internal joint stabilizer with a standardized protocol for posttraumatic complex persistent elbow instability. We performed total elbow replacements in patients older than 50 years who had advanced elbow arthritis. Based on that, 82% (18 of 22) of patients were eligible; 14% (3 of 22) were excluded because total elbow replacements was undertaken, and another 5% (1 of 22) were lost before the minimum study follow-up of 1 year (median 24 monthsThe study was funded by E-Da Hospital, Taiwan (EDAHP108035). Each author certifies that there are no outside funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. Ethical approval for this study was obtained from (E-Da Hospital)