1. Elbow Dislocation

2. 3-6% of all elbow injuries Peak: 13-14 yrs after closure of physes
High association with the following fractures
Medial epicondyle
Coronoid
Radial head and neck

3. Modified hinge joint Very stable Joint congruity
Opposing tension of triceps and flexors
Ligaments
Most important: Medial Collateral Ligament

6. Mechanism of Injury Fall on an outstretched hand o elbow
Causes unlocking of the olceranon from the trochlea + translation of the articular surfaces
2 types of dislocation
Posterior
Anterior

7. Malunion Discussion

8. Bone Healing Primary Secondary
Cortex attempts to heal without callus formation
Occurs when fx is anatomically reduced, the blood supply is preserved, and the fracture is rigidly stabilized
Secondary
Formation of callus
Involves participation of the periosteum and external soft tissues

9. 4 Stages of Fracture Healing
Hematoma formation (inflammation) and angiogenesis.
Cartilage formation with subsequent calcification
Cartilage removal and bone formation
Bone remodeling

11. Stage 1 - Hematoma Formation and Angiogenesis
< 1 week after a fracture
Transforming growth factor beta (TGF-) and platelet derived-growth factor (PDGF) are released from platelets at the fracture site
Osteogenic cells and inflammatory cells ensheathe the fracture and differentiate into chondrocytes or osteoblasts.
-Transforming growth factor beta (TGF-) and platelet derived-growth factor (PDGF) are released from platelets at the fracture
-Low-oxygen tension, low pH, and movement favor the differentiation into chondrocytes; high-oxygen tension, high pH, and stability predispose to osteoblasts

12. Stage 2 - Cartilage formation with subsequent calcification
~ 1 to 3 weeks after fracture
Radiologic evidence of mineral formation signals the onset of this phase.
consisting of calcified cartilage, woven bone made from cartilage, and woven bone formed directly.
Woven bone replaces cartilage in callus by active transport of minerals and their precipitation from a supersaturated solution

13. Stage 3 - Cartilage removal and bone formation
~ 1 to 3 months after fracture
woven-bone mineralized callus replaced by lamellar bone arranged in osteonal systems
3 characteristics:
It forms only under conditions of mechanical stability;
It has the ability to replace fibrous or muscle tissue; and
It forms within the confines of the bone defect

14. Stage 4 – Bone Remodelling
Can be around several years
meticulously coordinated removal of bone from one site and deposition in another.
Two lines of cells, osteoclasts and osteoblasts, are responsible for this process
Osteoclasts – resorption
Osteoblast - accretion

15. Malunion
Described to be a fractured bone that did not heal in an anatomic position
Bone may have:
Angulated
Rotated out of position
Overrided another bone
Causes shortening of the limb

16. Shortening is better tolerated in the upper limb
>1 inch poorly tolerated in the lower limb
Causes:
Inadequate immobilization
Misalignment
Premature removal of an immobilizer

17. Surgical Indication:
Pain
Impaired normal function

18. Non-union Healing by fibroblastic response instead of bone formation
Caused by:
Overdistraction
Excessive motion
Inadequate immobilization

19. Malunion vs. Non-union