Natural Bone Healing & Fixation

Natural Bone Healing

Stages of Natural Bone Healing

• Fracture healing passes through stages
• Movement at the fracture site initiates a healing process - callus formation
• Bleeding and clot formation is followed by migration of capillaries and fibroblasts into the broken area
• Vascular and cellular response leads to tissue differentiation and mineralization resulting in restoration of mechanical integrity

Characteristics of Natural Bone Healing

• The aim of fracture healing considered to be ‘cortex - to - cortex’ union, with fracture surfaces directly joining by bone.CCY????
• It requires the fracture to be immobilized in some way before it can occur.

Process of Natural Bone Healing

• Fractures are joined initially by a cuff of provisional woven bone (bridging external callus). This varies in amount.CCY ⇒
  • cortex - to - cortex union ⇒
  • late medullary callus ⇒
  • Remodelling and the gradual replacement of bridging bone by medullary callus

Detailed Stages of Natural Bone Healing

1. Hematoma formation

   • Hematoma

2. Fibrocartilaginous callus formation

   • Internal callus (fibrous tissue and cartilage)
   • External callus
   • New blood vessels
   • Spongy bone trabeculae

3. Bony callus formation

   • Bony callus of spongy bone

4. Bone remodeling

   • Healed fracture

Alternative Description of Fracture Healing Stages

1. Inflammation

   • Hematoma
   • Mesenchymal cells

2. Soft callus

   • Granulation tissue

3. Hard callus

   • Intramembranous bone formation
   • Enchondral ossification

4. Remodeling

Cascade of Tissue Differentiation

Following a fracture:

1. Hematoma
2. Granulation tissue
3. Connective tissue
4. Fibrocartilage
5. Mineral deposition
6. Bone

Tissue Differentiation Cascade

Healing Time & Strength

Process	Timing	Strength
Hematoma	2 hrs	1%
Inflammation	2 days	5%
Soft callus	2 weeks	25%
Hard callus	2 months	74%
Re-modeling	2 years	100%

Types of Bone Healing

Indirect Bone Healing

• Ordinary bone healing with callus formation occurs in conditions of relative stability
  • Fracture held stable (by cast/splint, or operative fixation)
  • Some movement is still possible

Direct Bone Healing

• With strong fixation and absolute stability Direct bone healing occurs without callus formation
• The rigid internal fixation with compression across the fracture takes the place of the callus. It may replace the first two processes of fracture healing

Conditions Necessary for Bone Healing

• Good blood supply
• Controlled motion
  • (Relative / Absolute Stability)
• No infection

Unfavorable Factors for Bone Healing

• Impairment of blood supply
• Infection
• Excessive movement (fracture not stable)
• Presence of tumor/cyst
• Interposition of soft tissue
• Any form of Nicotine (smoking)
• Bad nutrition

Average Healing Time

• Children:
  • Upper limb: 3-4 weeks
  • Lower limb: 2X upper limb (6-8 weeks)
• Adults:
  • Upper limb: 2X children (6-8 weeks)
  • Lower limb: 2X upper limb (12-16 weeks)

Aims of Fracture Treatment

• Aim of fracture treatment
  • Aid healing,
  • In normal position,
  • Avoiding complications

Principles of Fracture Treatment

• Treat the patient, not only the fracture
• Reduce the fracture
• Immobilize the fracture
  • Prevents displacement
  • Alleviates pain
  • Promotes soft tissue healing
• Mobilize the patient
• Avoid complications