outcome after open reduction and internal fixation of capitellar and trochlear fractures background capitellar and trochlear fractures are uncommon fractures of the distal aspect of the humerus there is limited information about the functional outcome of patients managed with open reduction and internal fixationmethods the functional outcome of twentyeight patients with a mean age and standard deviation of 43 13 years who were treated with open reduction and internal fixation for capitellar and trochlear fractures was evaluated at a mean duration of followup of 56 33 months patient outcomes were assessed with physical and radiographic examination rangeofmotion measurements strength testing and selfreported questionnaires short form36 mayo elbow performance index american shoulder and elbow surgeons elbow assessment form and patientrated elbow evaluation scalesresults eleven fractures involved the capitellum with or without fracture of the lateral ridge of the trochlea four involved the capitellum and trochlea as one piece and thirteen involved the capitellum and trochlea as separate fragments these fractures were further characterized by the presence or absence of posterior comminution fourteen patients had isolated fractures and fourteen had other elbow forearm or wrist injuries patients with more complex fractures required more extensive surgery had more complications resulting in secondary procedures and had poorer outcomes compared with those with simple fractures the average score on the mayo elbow performance index 91 11 the average qualityoflife scores 46 on the physical component and 50 on the mental component of the short form36 and the average range of motion 19 degrees to 138 degrees suggest favorable patient outcomes overall two comminuted fractures did not unite and required conversion to a total elbow arthroplastyconclusions patients with isolated noncomminuted capitellar andor trochlear fractures have better results than those with more complex fractures a classification system based on the radiographic patterns of these fractures is recommended