Fracture

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Fractures : 

Fractures Dr. R. P. PandeyDepartment of SurgeryCollege of Veterinary Sciences, Mathura

Definition & cause:- : 

Definition & cause:- Definition: Fracture is a complete or incomplete breach in the continuity of bone or cartilage. Causes: 1. Direct trauma at # site (75 to 80 % are HBC injuries) 2. Indirect trauma communicated to # site via bone/muscle (# of femur neck, tibial tuberosity, condyle of humerus or femur 3. Bone pathology causing weakening of bone and # by trivial trauma (neoplams, infections, metabolic bone diseases) 4. Repeated stress leading to fatigue # in racers (MC/MT # in Grey hounds).

Predisposition:- : 

Predisposition:- Congenital deformities (conformational) Smooth ground surface Pregnancy/lactation leading to > Ca++ Metabolic/pathological problems Concurrent musculoskeletal problems leading to uneven weight distribution etc.

Cardinal signs:- : 

Cardinal signs:- Pain (palpation / without palpation) Deformity (overriding/ distraction etc) Cripitus (serrated edges/comminution) Aobnrmal mobility (mobility at # site) Inability to bear weight (complete # long bones)

Fractures : 

Fractures Despite its mineral strength, bone may crack or even break if subjected to extreme loads, sudden impacts, or stresses from unusual directions. The damage produced constitutes a fracture. The proper healing of a fracture depends on whether or not, the blood supply and cellular components of the periosteum and endosteum survive.

Fracture Repair : 

Fracture Repair Step 1: Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. Bone cells at the site become deprived of nutrients and die. The site becomes swollen, painful, and inflamed. Step 2: Granulation tissue is formed as the hematoma is infiltrated by capillaries and macrophages, which begin to clean up the debris. Some fibroblasts produce collagen fibers that span the break , while others differentiate into chondroblasts and begin secreting cartilage matrix. C. Osteoblasts begin forming spongy bone. D. This entire structure is known as a fibrocartilaginous callus and it splints the broken bone.

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Step 3: Bone trabeculae increase in number and convert the fibrocartilaginous callus into a bony callus of spongy bone. Typically takes about 6-8 weeks for this to occur. Fracture Repair Step 4: During the next several months, the bony callus is continually remodeled. Osteoclasts work to remove the temporary supportive structures while osteoblasts rebuild the compact bone and reconstruct the bone so it returns to its original shape/structure.

Fracture Types : 

Fracture Types Fractures are often classified according to the position of the bone ends after the break: Open (compound)  bone ends penetrate the skin. Closed (simple)  bone ends don’t penetrate the skin. Comminuted  bone fragments into 3 or more pieces. Common in the elderly (brittle bones). Greenstick  bone breaks incompletely. One side bent, one side broken. Common in children whose bone contains more collagen and are less mineralized. Spiral  ragged break caused by excessive twisting forces. Sports injury/Injury of abuse. Impacted  one bone fragment is driven into the medullary space or spongy bone of another.

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What kind of fracture is this? It’s kind of tough to tell, but this is a _ _ _ _ _ _ fracture.

Bone Remodeling : 

Bone Remodeling Bone is a dynamic tissue. What does that mean? Wolff’s law holds that bone will grow or remodel in response to the forces or demands placed on it. Examine this with the bone on the left.

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Check out the mechanism of remodeling on the right! Why might you suspect someone whose been a powerlifter for 15 years to have heavy, massive bones, especially at the point of muscle insertion? Astronauts tend to experience bone atrophy after they’re in space for an extended period of time. Why?

Bone Remodeling : 

Bone Remodeling Bone is a dynamic tissue. What does that mean? Wolff’s law holds that bone will grow or remodel in response to the forces or demands placed on it. Examine this with the bone on the left.

Slide 14: 

Check out the mechanism of remodeling on the right! Why might you suspect someone whose been a powerlifter for 15 years to have heavy, massive bones, especially at the point of muscle insertion? Astronauts tend to experience bone atrophy after they’re in space for an extended period of time. Why?

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Increased PTH release by parathyroid gland Binds to osteoblast causing decreased osteoblast activity and release of osteoclast-stimulating factor OSF causes increased osteoclast activity Decreased bone deposition and increased bone resorption Increased calcitriol synthesis Increased intestinal Ca2+ absorption Decreased Ca2+ excretion Increased Blood [Ca2+] Decreased Blood [Ca2+]

Healing of Fracture:- : 

Healing of Fracture:- Events: 1. Haemorrhage in the area 2. Clot formation 3. Inflammation and edema 4. Cell proliferation 5. Cartilage & Bone formation 6. Remodelling

Slide 17: 

Blood supply of long bone

Slide 18: 

Healing of Fracture - A

Slide 19: 

Healing of Fracture - B

Slide 20: 

Healing of Fracture - C

Slide 21: 

Healing of Fracture - D

Slide 22: 

Inflammatory response -Time of injury to 24-72 hours (No. 1) Reparative response -2 days to 2 weeks (No. 2 & 3) Consolidation & remodeling-Middle of repair phase up to 7 years (No. 3 & 4) Healing of Fracture - Summary of events

Slide 23: 

Injured tissues and platelets release vasoactive mediators, growth factors and other cytokines. The cytokines influence cell migration, proliferation, differentiation and matrix synthesis.   Growth factors recruit fibroblasts, mesenchymal cells & osteoprogenitor cells to the fracture site. Macrophages, PMNs & mast cells (48hr) arrive at the fracture site to begin the process of removing the tissue debris. Inflammatory response -Time of injury to 24-72 hours:-

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Reparative response -2 days to 2 weeks :- Vasoactive substances (Nitric Oxide & Endothelial Stimulating Angiogenesis Factor) cause neo-vascularisation & local vasodilation Undifferentiated mesenchymal cells migrate to the # site having the ability to form cells which in turn form cartilage, bone or fibrous tissue (ref.O2). The # haematoma is organised and fibroblasts and chondroblasts appear between the bone ends and cartilage is formed. The amount of callus formed is inversely proportional to the amount of immobilisation of the #. In fractures fixed with rigid compression plates primary bone healing with little or no visible callus formation can be obtained.

Slide 25: 

Consolidation & remodeling - Middle of repair phase up to 7 years :- Remodeling of the woven bone is dependent on the mechanical forces applied to it (Wolff’s Law - 'form follows function’) Fracture healing is complete when there is repopulation of the medullary canal. Cortical bone: Remodeling occurs by invasion of an osteoclast “cutting cone” which is then followed by osteoblasts which lay down new lamellar bone (osteon). Cancellous bone: Remodeling occurs on the surface of the trabeculae which causes the trabeculae to become thicker.

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Systemic Local Age Degree of local trauma Hormones Degree of bone loss Functional activity Vascular injury Nerve function Type of bone fractured Nutrition Degree of immobilisation Drugs (NSAID/SAID) Infection Local pathology Factors influencing bone healing:-

Slide 27: 

Hormonal influences on bone healing:- Hormone Effect Mechanism Cortisone < Decreased callus production Calcitonin > Unknown TH/PTH > Bone remodeling GH > Increased callus volume Androgens > Increased callus volume

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Age of animal External & IMP Bone plates Under 3 months 2-3 weeks 4 weeks 3-6 months 4-6 weeks 2-3 months 6-12 months 5-8 weeks 3-5 months Over 1 year 7-12 weeks 5 months -1 year Rate of Clinical Union (Average healing time):- (Clinical union is the time when immobilization can be removed)

Slide 29: 

Healing of Fracture - Possibilities & hope

Slide 30: 

Classification-Patterns of #

Slide 31: 

Classification-Patterns of # # in young subjects (K-L) Epiphyseal #

Classification:- : 

Classification:- A. Presence of wound Closed or simple # 2. Open or compound # First Degree: Penetration from inside by fractured bone. Second Degree: A contused wound inflicted from the outside. Third Degree: Extensive skin, muscle, and possible nerve damage with a comminuted fracture. Wounding occurs from outside

Classification:- : 

Classification:- B. Extent of damage (ref. fig.) 1. Complete # 2. Green stick # (in young ones, Periosteal and cortical bone discontinuity at convex side) 3. Fissured # (spiral or longitudinal cracks in the cortex with intact [?] periosteum.

Classification:- : 

Classification:- C. Direction of # line 1. Transverse # 2. Oblique # 3. Spiral # 4. Segmental # 5. Comminuted #

Classification (conti.):- : 

Classification (conti.):- C. Direction/location of # line 6. Impacted #

Classification (conti.):- : 

Classification (conti.):- C. Direction/location of # line 7. Avulsion # 8. Physeqal # 9. Condylar # Unicondylar Bicondylar

Classification:- : 

Classification:- D. Stability on reduction 7. Stable # (transverse/green/ stick/impacted) 8. Unstable # (oblique/comminuted/multiple)

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