#primary healing Parren's strain hypothesis Contact healing Gap healing Cutting cone Comparison between contact and gap healing

1. Primary Healing
PRESENTED BY- SUPARNA BANDYOPADHYAY

2. Fracture is breach in the structural continuity of the bone and cortex
with a degree of injury to the surrounding soft tissues
Fracture
Healing of fracture
It is an intricate and fluent regenerative process that aims at restoring
the damaged bone to its pre-injury state and cellular composition

3. Parren’s Strain Hypothesis
Inter fragment strain = ΔL/L X 100%
ΔL= Relative Displacement Of Fracture Fragment
L= Initial Gap Between Fracture Fragment

4. Direct or Primary healing
 Direct healing occurs through direct remodeling of the lamellar bones.
 This process usually takes a month to years.
Direct healing occurs:
Following anatomical reduction of fracture fragments
When the fracture fragments are more stable, and
stability is achieved by lag screw or compression plate
Vascular supply is good

5. Contact healing
Cutting cones
Osteoblast lay down the new bone in the
tunnel created by the osteoclast
Lamellar bone formation
Bony union in axial direction (parallel to
the bone)

6. Gap healing
Fracture site filled with lamellar bone
which runs perpendicular to the long axis
of the bone
Primary bone structure is eventually
replaced by longitudinal
revascularized osteons similar to the
cutting cones
3-8 weeks

7. Primary Healing
Gap Healing
 Inter fragment gap is less than 1mm
Lamellar bone formed perpendicular to the axis
Can be done following rigid fixation
Cutting cones
Fragment strain is less than 2%
Healing occurs through the lamellar bone formation
Contact Healing
Inter fragment gap is less than 0.01mm
Lamellar bone formed parallel to the axis
Can be done following rigid fixation
Cutting cones
Fragment strain is less than 2%
Healing occurs through the lamellar bone formation

8. Thank you