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Objective: Scaphoid and lunate fractures have a relatively high incidence rate. Traditional carpectomy and carpal arthrodesis in the treatment of carpal osteonecrosis will lead to many complications. Three-dimensional (3D) printed tantalum has good biocompatibility and can be designed to match the patient’s personalized anatomical carpal structure. This study aims to investigate carpal function and prosthesis-related conditions after carpal bone replacement using 3D printed tantalum prostheses.Methods: From July 2020 to January 2022 at our center, seven patients with osteonecrosis of the carpus received carpal bone replacement using 3D printed tantalum prosthesis. The Disability of the Arm, Shoulder and Hand (DASH) score and patient satisfaction, as well as the Mayo Wrist Scores (Cooney method, modified Green, and O’Brien wrist score), were used to evaluate the preoperative and postoperative wrist function of patients. The Visual Analog Scale (VAS) pain scores were also recorded before and after surgery. The angles of flexion, dorsiflexion, ulnar deviation, and radial deviation were measured using an arthrometer. The grip strength and pinch strength of the operated hand after carpal bone replacement and the contralateral healthy carpus were measured using a dynamometer. Radiographs were taken to confirm the condition and complications of the tantalum prosthesis.Results: All seven patients were followed for 19.6 ± 2.7 months. At the last follow-up, the grip strength of the operated wrist joint after carpal bone replacement was 33.4 ± 2.3 kg, the pinch strength was 8.9 ± 0.7 kg, the flexion was 54.6° ± 0.8°, the dorsiflexion was 54.7° ± 1.7°, the ulnar deviation was 34.6° ± 1.9°, and the radial deviation was 25.9° ± 0.8°, all of which showed no statistically significant difference with the contralateral healthy carpus (p > 0.05). There were significant differences in the VAS, DASH, and MAYO scores between the preoperative and the last follow-up (p < 0.01). Patients had reduced postoperative pain and improved wrist function and range of motion (ROM), and the tantalum prostheses were stable.Conclusion: The 3D printed tantalum brings us new hope, not only for hip or knee replacement, but also for joint replacement of other complex anatomical structures, and patients with other irregular bone defects such as bone tumors and deformity, which could realize personalized treatment and precise medicine.

Fractures of the radial head account for 33% of elbow fractures. More and more studies have found that the radial head plays an important role in the normal function of the elbow joint, and many complications will occur after resection of the radial head. Accurate treatment of radial head fractures is crucially important. At this stage, commercialized radial head prosthesis of fixed size is commonly used in radial head replacement, but the mismatch of prosthesis and material problems have resulted in many complications. The three-dimensional (3D) printed porous tantalum has good biocompatibility, is conducive to bone ingrowth, has ideal elastic modulus, and can be prepared into a highly porous material that can be designed to match the radial head according to each patient's personalized anatomical structure. The purpose of this study was to investigate the elbow joint function, complications and prosthesis conditions after radial head replacement using 3D printed porous tantalum. Seven patients with comminuted fracture of radial head in our Center received radial head replacement using 3D printed porous tantalum. Patients were followed on the elbow joint function, range of motion (ROM), elbow radiographs, postoperative complications, and bone condition of tantalum metal. quality situation. Follow-up data showed that the patients had less postoperative pain, improved elbow function and ROM, and bone ingrowth in the tantalum prosthesis. The 3D printing porous tantalum can be applied to hip replacement, knee replacement, and other patients with irregular bone defects such as bone tumor, bone deformity, etc., which has the potential to realize personalized and precise treatment.