Three-dimensional (3D) bio-printing is a novel engineering technique by which the cells and support materials can be manufactured to a complex 3D structure. Compared with other 3D printing methods, 3D bio-printing should pay more attention to the biocompatible environment of the printing methods and the materials. Aimed at studying the feature of the 3D bio-printing, this paper mainly focuses on the current research state of 3D bio-printing, with the techniques and materials of the bio-printing especially emphasized. To introduce current printing methods, the inkjet method, extrusion method, stereolithography skill and laser-assisted technique are described. The printing precision, process, requirements and influence of all the techniques on cell status are compared. For introduction of the printing materials, the cross-link, biocompatibility and applications of common bio-printing materials are reviewed and compared. Most of the 3D bio-printing studies are being remained at the experimental stage up to now, so the review of 3D bio-printing could improve this technique for practical use, and it could also contribute to the further development of 3D bio-printing.
Objective To investigate the effectiveness of arthroscopic autologous iliac bone grafting with double-row elastic fixation in treatment of recurrent anterior shoulder dislocation combined with massive glenoid bone defects. Methods Between January 2018 and December 2021, 16 male patients with recurrent anterior shoulder dislocation combined with massive glenoid bone defects were treated with arthroscopic autogenous iliac bone grafting and double-row elastic fixation. The patients were 14-29 years old at the time of the first dislocation, with an average age of 18.4 years. The causes of the first dislocation included falling injury in 5 cases and sports injury in 11 cases. The shoulders dislocated 4-15 times, with an average of 8.3 times. The patients were 17-37 years old at the time of admission, with an average age of 25.1 years. There were 5 left shoulders and 11 right shoulders. The preoperative instability severity index (ISIS) score of the shoulder joint was 5.8±2.1, and the Beighton score was 4.3±2.6. The University of California Los Angeles (UCLA) score, Constant score, American Shoulder and Elbow Surgeons (ASES) score, and Rowe score were used to evaluate shoulder function, and the degree of the glenoid bone defect repair was observed based on CT after operation. Results All incisions healed by first intention, and no complication such as incision infection or neurovascular injury occurred. The patients were followed up 12 months. At 12 months after operation, UCLA score, Constant score, ASES score, and Rowe score all significantly improved when compared with the scores before operation (P<0.05). CT imaging showed the degree of glenoid bone defect was significantly smaller at immediate, 6 and 12 months after operation when compared with that before operation (P<0.05), and the bone blocks healed with the scapula, and bone fusion had occurred at 12 months. ConclusionArthroscopic autologous iliac bone grafting with double-row elastic fixation is a safe treatment for recurrent anterior shoulder dislocation combined with massive glenoid bone defects, with good short-term effectiveness.