Introduction: This case report describes the reconstruction of a severe comminuted fracture and bone defect in the lateral half of the clavicle using a novel titanium prosthesis. This unique prosthesis has been specifically designed and three dimensionally printed for the clavicle, as opposed to the Oklahoma cemented composite prosthesis used in common practice. The aims of this study were to: (1) describe the prosthesis, its stress analysis, and its surgical fixation and (2) to demonstrate the results of the 2-year follow-up of the patient with the lateral clavicle prosthesis. Patient's Main Concerns: A 20-year-old, right-handed woman complaining of severe pain in the right shoulder was admitted to our hospital following a traffic accident. Physical examination revealed pain, swelling, tenderness, limb weakness, asymmetric posturing, and loss of function in the right shoulder. Diagnosis, Intervention, and Outcomes: Radiographic evaluation in the emergency room showed complete destruction with a comminuted fracture of the lateral half of the right clavicle and a comminuted fracture of the coracoid. We designed a new prosthesis for the lateral half of the clavicle, which was then tested by finite element analysis and implanted. Use of the new prosthesis was effective in the reconstruction of the comminuted fracture in the lateral half of the clavicle. After 2 years of follow-up, the patient had an aesthetically acceptable curve and was able to perform her activities of daily living. Her pain was relieved, and the disabilities of the arm, shoulder, and hand score improved. Active range of motion of the shoulder joint and muscle strength were also improved. Conclusion: This novel prosthesis is recommended for reconstruction of the lateral half of the clavicle following development of bony defects due to fracture. Our patient achieved functional and aesthetic satisfaction with this prosthesis.