Characteristics

Typically, a non-united fracture, is not painful on movement unlike that of a fracture with delayed union.

Two types of non-union are distinguished on the basis of x-ray or isotope uptake on bone scan:

• hypertrophic or vascular - the fracture is trying to heal and is characterised by a massive cuff of bone around the ends of the fracture fragments. The radiologic appearance is likened to an elephant's foot due to the large surface area which also makes movement about the fracture stiff on examination
  
  
• atrophic or avascular - the bone ends show no sign of healing and come to a point. Some patients also develop a synovial pseudoarthrosis. The fracture is extremely mobile with a significant gap between the fragments filled with fibrous tissue