Preoperative radiograph: The radiograph indicated a transverse fracture of the left patella, with the fracture end separated and displaced by about 2 cm, and the joint surface was uneven. Pre-operative radiographs Post-operative radiographs For the transverse patella fracture, the Department of Orthopaedic Hospital Arthroplasty was the first to carry out closed reduction of the patella under arthroscopic surveillance with internal fixation with tension bands. Arthroscopic exploration of patellar fracture repositioning The advantages of using arthroscopic treatment for patellar fracture are: A. It provides a good intra-articular view directly to understand the damage of other structures in the joint and helps to determine further treatment plan. B. It can be repeatedly irrigated to remove clots, fibrinous exudate and bone and cartilage fragments. C, direct observation of the patellofemoral articular surface, in patellar repositioning, the position of the upper and lower fracture blocks can be adjusted at any time according to the alignment. D.Probes and other instruments can be applied internally and externally to basically ensure fracture repositioning. E. Directly observe the repositioning effect of the patellofemoral articular surface after the completion of internal fixation. F.After the completion of internal fixation, the fracture of the joint capsule and the expanded quadriceps tendon on both sides of the patella can be directly observed to determine whether to perform skin incision and suture repair. G. The whole operation is less traumatic, the joint cavity is basically not exposed, and the chance of infection is small, which is conducive to early postoperative functional exercises. H. The length of hospital stay is reduced.