Depending on the viability of the fracture end, there are abundant (hypertrophic) and ischemic (atrophic) bone discontinuities. In the former, the fracture ends are regenerative and produce a significant biological response. The rich bone discontinuity can be divided into different subtypes: (1) “elephant’s foot” type bone discontinuity: the fracture end has hypertrophic and abundant bone scabs, and the fracture end has vitality, the bone discontinuity is mainly caused by poor fixation after fracture repositioning, insufficient braking or premature weight bearing; (2) “horseshoe (2) “Horseshoe” type bone discontinuity: the fracture end is mildly hypertrophic with less bone crust, mainly due to insufficient plate and screw fixation, the formed bone crust is not enough to connect the fracture end, and there may be a small amount of sclerosis; (3) Dystrophic bone discontinuity: the fracture end is non-hypertrophic, lacks bone crust, and mainly occurs in obvious displacement, separation or inaccurate alignment during internal fixation. Ischemic osteonecrosis with lack of viability of the fracture end, little biological response, and poor blood supply to the fracture end. (1) torsional wedge: a fracture with a lack of or no blood supply between the two fracture ends; (2) comminuted bone discontinuity: the presence of one or more dead bone fragments without any crust formation on x-ray; (3) defective bone discontinuity: the fracture end is viable but cannot be joined over the defect; (4) atrophic bone discontinuity: the absence of the middle bone fragment is caused by scar tissue that lacks osteogenic potential caused by filling, with atrophy and osteoporosis at the fracture end. Type A is divided into movable deformity (type A1) and fixed deformity (type A2), which is further divided into non-deformed ankylosing bone discontinuity (type A2-1) and deformed ankylosing bone discontinuity (type A2-2). type B is further divided into Type B is divided into bone loss (type B1), bone length loss (type B2), and bone loss with bone length loss (type B3).