Abstract:[Objective] To introduce the surgical technique and primary clinical outcomes of 3D printed polyetheretherketone prosthesis for defect reconstruction secondary to en bloc resection of clavicular malignant tumor. [Methods] A total of 5 patients underwent abovementioned surgical treatment for clavicular malignancy. The lesion involved the lateral segment of the clavicle in 3 cases, while the medial segment in 2 cases, with pathological fracture in 2 cases. After computer modeling based on the shape of the clavicle on the healthy side of the patient, personalized prosthesis and osteotomy guide plate were prepared by 3D printing. The sternoclavicular ligament or acromioclavicular ligament was cut off according to the location of the tumor during the operation, and the osteotomy guide was used to assist the osteotomy on the other side to remove the tumor segment en bloc. The personalized prosthesis prepared by 3D printing was implanted, and connected and fixed with the normal clavicle at the reserved end by using locking plates, with reattachment of the sternoclavicular ligament or acromioclavicular ligament by anchor sutures. [Results] All the patients were successfully operated on without nerve, vascular injury and other complications, got incisions healed in stage I without infection. The patients were followed up for 2 to 26 months, had the shape and function of the shoulder recovered well after the operation. No local tumor recurrence was found during the follow-up period, and no obvious rejection and other complications were observed. [Conclusion] The 3D printed polyetheretherketone prosthesis for defect reconstruction secondary to en bloc resection of clavicular malignant tumor is a feasible technique, and achieves satisfactory clinical consequences in short-term.