All are True about fracture healing except :
Compression at fracture site improves healing by inducing callus formation Compression enhances the rate of union in cancellous bone. In coical bones, compression at the fracture site enhances rigidity of fixation, and possibly results in primary bone healing. Ref: Maheshwari 9th ed pg 12.
Nutrition affects healing
Stable fixation promotes healing
Compression at fracture site causes nonunion
Hormonal status may affect healing
Anatomy and physiology of bone and fracture healing