Comminuted fracture of the coronoid process usually occurs in patients with serious elbow injuries, such as fracture of the terrible triad and transolecranon fractures. Unfortunately, this fracture is challenging for some surgeons because of complications and poor clinical outcomes due to conflicts between elbow stability and early motion. Even though the O'Driscoll classification is used for ordinary fractures [1], several kinds of fixation, such as nonabsorbable sutures, wiring, and plates/screws, have been reported to yield promising outcomes [2], [3], [4]. However, in comminuted, multifragmentary coronoid fractures, especially those involving the basal area, certain kinds of fixation tool cannot provide their own stability against posterior dislocation due to the loss of anatomical geometry for the buttress role.

Furthermore, our authors encountered several comminuted coronoid fractures with partial loss of articular defects (CCFPLAC) over a few decades. Thus, overall restoration of their original shape and height requires meticulous manipulation of the multiple fragments and firm fixation. Due to the importance of precise restoration of the original bony anatomy, the concept of the design of coronoid prostheses was recently introduced by O'Driscoll [5]. Afterward, the coronoid prosthesis received attention, as it allowed for elaborate restoration of elbow integrity while avoiding the pitfall of grafting [5]. In particular, patient-specific prostheses produced by 3-dimensional (3D) printing are emerging as novel tools for treating complicated coronoid fractures in which the collapsed structure is stable. However, the longevity of the prosthesis has not yet been established. Additionally, the most important factor influencing the longevity of prostheses is the fixation method used; therefore, additional investigations need to be performed to evaluate the promotion of osseous integration and the minimization of loosening [6,7].

We have tried to restore the arc by considering trochlear-coronal articulation as a complete circle during fixation of the coronoid, even for CCFPLAC, using various kinds of locking plates. The purpose of this retrospective study was to report the radiological and clinical outcomes after the fixation of basal-1 type CCFPLAC (according to the O'Driscoll classification) using our method.