- See: Bone Topics 
 
- Discussion:
    - woven bone healing:
          - ref: Distal radial fractures heal by direct woven bone formation
    - stages of enchondral bone healing:
          - hematoma / inflammation:
                 - shortest stage of fracture healing
                 - disruption of vascular flow through the marrow and periosteum
                 - infiltration of hematopoietic cells for hematoma formation, phagocytosis,
                           and reparative cytokine production
                 - ref: Human Early Fracture Hematoma Is Characterized by Inflammation and Hypoxia
          - endochondral ossification (chondrogenesis)
                 - low oxygen tension where woven bone develops to stabilize the fracture
          - remodeling / intramembranous ossification:
                 - strain results in the formation of collagen and intramembranous ossification;
                 - neovascularization, differentiation of mesenchymal stem cells into osteoblasts
                 - replacement of the cartilaginous callus by bone callus with remodeling;
                 - references:
                        - The four biomechanical stages of fracture repair. 
                        - Evidence for a humoral mechanism for enhanced osteogenesis after head injury.
                        - The biology of fracture repair. 

          - bone healing w/ plates: 
                  - pure compression and hydrostatic pressure causes mesenchymal cells to differentiate to chondrogenesis
                            and endochondral ossification;
                  - references:
                         - Evolution of the internal fixation of long bone fractures. choosing a new balance between stability and biology.
                         - Comparison of the effects of compression plates and external fixators on early bone-healing.
                         - Bone-healing patterns affected by loading, fracture fragment stability, fracture type, and fracture site compression.
                         - Motion Predicts Clinical Callus Formation: Construct- Finite Element Analysis of Supracondylar Femoral Fractures.
                         - Dynamic Stabilization with Active Locking Plates Delivers Faster, Stronger, and More Symmetric Fracture-Healing

    - bone vascular supply:
          - fracture healing depends on adequate blood supply.
                  - The vascular response to fracture micromovement.
                  - The effects of extraperiosteal and subperiosteal dissection. II. On fracture healing.
                  - The effects of extraperiosteal and subperiosteal dissection. I. On blood flow in muscle. 
         - fracture healing depends on periosteum:
                  - Periosteal and perichondral grafting in reconstructive surgery. 
                  - The presence of periosteum is essential for the healing of large diaphyseal segmental bone defects reconstructed with trabecular metal: a study in the femur of goats.
                  - The induction of neochondrogenesis in free intra-articular periosteal autografts under influence of CPM.

- Radiographic Determinants of Healing:  (non union)
          - restoration of cortical continuity (look for healing on 4 cortices - AP and lateral views); 
          - loss of distinct fracture line;
          - presence of callus (w/ IM nail or external fixator); 
          - references:
                  - Accuracy of radiologic assessment of tibial shaft fracture union in humans
                  - Correlations of radiographic analysis of healing fractures with strength: a statistical analysis of experimental osteotomies.  
    - age: 
          - references:
                   - Aging of bone tissue: mechanical properties.
                   - Age-related changes in properties of cortical bone. The importance of porosity, mineralization, and microstructure.
                   - Structural and cellular changes during bone growth in healthy children. 

- Negative Influences on Bone Healing: 

- Positive Influences on Bone Healing:

- Labs to Promote Bone Healing:
         - vitamin D, B12, DHEA, testosterone, E1, and E2, liver enzymes, and parathyroid hormone level.
         - ref: A study of male patients with forearm fracture in Northern Ireland.

- Induction of Bone Healing:
      - autograft / allografts:
      - bone morphogenic proteins: 
      - ultrasound:
              - Low intensity pulsed ultrasound accelerates delayed healing process by reducing the time required for the completion of endochondral ossification in the aged mouse femur fracture model.

      - electrical properties of bone:
              - bone loaded in compression will cause an electronegative field;
              - bone loaded in tension will cause an electropositive field;
              - references:
                       - Treatment of recalcitrant non-union with a capacitively coupled electrical field. A preliminary report.
                       - Intraoperative measurement of bone electrical potential: a piece in the puzzle of understanding fracture healing. 

The biology of fracture healing in long bones
Repair of segmental bone defects in the rat: an experimental model of human fracture healing.
Effect of intense physical activity on the bone-mineral content in the lower limbs of young adults.
Humeral hypertrophy in response to exercise.
The science of fracture healing.
Indirect reduction brought surgeons back to basics
Immobilizing the fracture: nonsurgical fracture treatment
Non Sine Gloria
Use of clinical assessment tools in the evaluation of fracture healing