The coronoid process is the most important articular stabilizer of the elbow. While most large coronoid fractures are treated surgically with open reduction and internal fixation, there is limited data on the most effective fixation method. The strengths of five different coronoid fixation methods were assessed using a materials testing machine. Plate fixation proved to be stronger than screw fixation;​ two screws, regardless of the orientation, were stronger than one;​ and suture fixation was unreliable. In the setting of an unfixable coronoid fracture, reconstruction of the coronoid using the tip of the olecranon has been described. However, this technique has not been evaluated biomechanically to verify its effectiveness. Using an elbow motion simulator, elbow kinematics were examined after a 40% coronoid deficiency and following reconstruction using the tip of the ipsilateral olecranon. The coronoid deficiency resulted in significant alterations in elbow kinematics, but these were restored after reconstruction. Nonetheless, when coronoid reconstruction is not possible, coronoid replacement may be required. Using the elbow simulator, the effects of coronoid replacement with a novel anatomic and extended tip prosthesis after a 40% coronoid deficiency were examined with the collateral ligaments both repaired and insufficient. When the collateral ligaments were repaired, both prostheses restored stability to the coronoid-deficient elbow. In the setting of ligament insufficiency, an extended prosthesis reduced elbow laxity relative to the anatomic prosthesis, yet was still less stable than the intact elbow with repaired ligaments.