Abstract
In the discussion concerning the theory of the healing of shaft fractures the demand for absolute stability of the fracture has been a dominating factor. This cannot be an absolute prerequisite because fractures of the tibia or femur heal well even with continued weight-bearing and movement. the ingrowth of vessels is apparently not a crucial factor. It is evident, however, that fractures caused by direct violence with soft tissue damage heal more slowly than fractures caused by indirect violence, irrespective of the treatment. Soft tissue heals with fibrous scar; fractures heal by bone regeneration. the author postulates that the damaged tissue stimulates (possibly via molecular determinants) the structural genes of undifferentiated cells to produce mRNA and proteins for either fibrous tissue or bone formation. the rate of healing of the fracture is determined by the degree of bone damage in relation to soft tissue damage. in fractures with extensive soft tissue injury there occurs a competitive condition in the common haematoma, with a risk of delayed fracture healing due to the dominance of cells that are triggered off by fibrous tissue formation.