This document summarizes principles of fracture fixation, methods that provide absolute versus relative stability, and Perren's strain theory. Absolute stability results in primary bone healing without callus formation, while relative stability stimulates callus formation and secondary bone healing. Simple fractures benefit from absolute stability using techniques like lag screws or compression plates, while multifragmentary fractures typically use relative stability with bridging plates, intramedullary nails, or external fixation. The goal is anatomical reduction and rigid fixation for intra-articular fractures, and alignment with relative stabilization for multifragmentary diaphyseal fractures.

1. +
Principles of fracture
fixation

2. +
Absolute stability
No micromotion in the fracture  healing by
primary (direct) bone without callus formation

3. +
Relative stability
There is some motion in the fracture
fragments  stimulation of callus formation
 secondary bone healing by callus
formation

4. + Perren's strain theory

5. +
Fracture Simple fracture
(<2 mm)
Multifragmentary
(>2 mm)
Relative stability Bone resorption,
healing delay, or
nonunion
Secondary bone
healing (callus)
Absolute stability Primary bone
healing, osteonal
remodelling
Bone resorption,
healing delay, or
nonunion

6. +
Methods of absolute stability
Compression by Lag Screw

7. +
Compression plate

8. +
Dynamic compression by Tension band

9. +
Methods of relative stability
Bridging plate

10. +
intramedullary nailing

11. +
External fixation

12. +
Home message
 Simple diaphysialfracture anatomical reduction and
absolute stabilization
 Intraarticular fracture  anatomic congruity of the joint
surface must be restored and the fragments should be
fixed rigidly by interfragmentary compression
 Diaphysialmultifragmentaryfracture god alignment in all
planes and relative stabilization.

13. +
References:
 AO Principles of Fracture Management: Thomas P. Ruedi , William M. Murphy
 Rockwood and Green's Fractures in Adults