Fig. 1

Procedures of tension-free external immobilization. A An anterior median incision of the patella was made to expose the fracture end. B The fracture end was sutured in a knee-extension position. C Kirschner wires were cross-inserted in the vertical direction of the waist segment of the patella and fixed with the ^1/2 ring. D The two ^2/3 rings were bridged and fixed with Kirschner wires and threaded needles on the plane of tibial tubercle and two distal planes. E The devices at the patellar end and the tibial end were connected and fixed using the joint hinge, and the joint motion and tension-free state of the fracture end were maintained