FRACTURE HEALING Dr. Mohit - PowerPoint Presentation

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FRACTURE HEALING

Dr.

Mohit

Dhingra

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DEFINITON OF FRACTURE

It’s a break in the continuity of bone With partial or total disruption of blood supply to the region of boneSeen radiologically as uni or bicortical break.

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DEFINITION OF FRACTURE REPAIR

Is a systematic and organized cascade of events for the regeneration of tissue with influence of local and systematic factors

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FRACTURE REPAIR

It’s a regenerative process rather than healingAs the defect is replaced by new bone rather than scar tissue.

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FRACTURE REPAIR

It’s a continuous process in which bone is Formed Replaced Remodeled

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FACTORS AFFECTING FRACTURE REPAIR

Local factorsType of bone (normal or pathological)Type of fracture ( open or closed)Intra articular fractureSurrounding soft tissue injurySingle or both bone fractureLocal bone pathology like cystInfectionVenous stasisType of treatment and fixation

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FACTORS AFFECTING FRACTURE REPAIR

Systemic factorsAgeActivity levelNutritional statusHormonal factorsVitamin and mineral deficiencyDiabetes mellitusPatient on drugs like chemotherapy, steroidsSmokingAlcohol abuseHead injury

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TYPES OF FRACTURE REPAIR

3 types

Intramembranous repair (direct bone healing)

Creeping substitution

Repair with bone callus formation (indirect bone healing)

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INTRA MEMBERANEOUS REPAIR

No callus formationBone heals directlySeen in rigid fixation such as platingThis occurs when the gap after fixation is below 500 micronsCutting cones crosses from one side to another

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INTRA MEMBERANEOUS REPAIR

Healing passes through following stagesResorption of bone ends- due to compression at fracture site Fibrous tissue formation- formed from healing hematoma composed of collagen3. Maturation to lamellar bone- Haversian remodeling occurs across fracture site. Osteoclastic front is followed by osteoblastic ossification and laying of thin capillaries.

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CREEPING SUBSTITUTION

Primarily seen in cancellous boneSeen around intra and peri articular fracturesIt’s a process of resorption of trabecular networkLying of new bone by appositional ossification on the surface of scaffoldThe inflammatory cells and granulation tissue creeps and new bone is thus formed

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CREEPING SUBSTITUTION

This sandwich of necrotic bone surrounded by viable new bone is remodeledGross architecture of the bone is maintainedScaffold is copy pasted by new living bone

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SECONDARY BONE HEALING

This refers to passing through the stage of callus formationCallus is pre-ossification cartilage tissue which is formed in response to controlled motion over fracture site

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SECONDARY BONE HEALING

Three stagesReactive (Inflammatory) stageHematoma formationGranulation tissue formation2. Reparative stageCallus formation soft callus hard callusConsolidation3.Remodelling stage

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INFLAMATORY STAGE

Hematoma formationBlood leaks into the surrounding tissue due to disruption of vessels, periosteum and endosteumInduces local inflammatory responseStarts regional acceleratory phenomenon

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INFLAMATORY STAGE

Stage of hematoma formation

Osteoblast comes from bone marrow and mesenchymal cells from cambium layer of periosteum

Osteoclast come from hematopoietic cells of bone marrow

BMP

BMP

Migrate to the fracture focus

TGF-beta and platelet derived growth factor

Colony forming unit fibroblast

Granulation tissue

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INFLAMATORY STAGE

Granulation tissue formation

hematoma

vessels

Vascular endothelial growth factor and fibroblast growth factor

Fibro vascular granulation tissue-

type II collagen

This stage

last for 2 weeks

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REPARATIVE STAGE

It comprises of two stages-Callus formation stage soft callus (primary callus) hard callusConsolidation (lamellar bone deposition)

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REPARATIVE STAGE

Callus formation-It’s a regenerative tissue formed in response to micro motion at the injury site.The formation is combined effect of four distinct healing responses Bone marrowBone cortexPeriosteumExternal soft tissue

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REPARATIVE STAGE

Soft callus-Starts forming after 2 weeks4 types-Periosteal bridging callusIntramedullary callusIntercortical uniting callusExternal soft tissue callus

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REPARATIVE STAGE

Periosteal bridging callusIntramedullary callus

Cells from cambium layer develop into osteoblast and deposit the organic matrix

Laid down from inside the bone

It’s a double concave shape

Predominant response during gap repair

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REPARATIVE STAGE

Intercortical uniting callusExternal soft tissue response

Occupy the space between opposed cortices of fracture ends

Develop from vascular mesenchymal tissue like muscles and is important in fracture repair

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REPARATIVE STAGE

Hard callusTransformation of woven bone into primary lamellar bone Commences in 4th week and finishes around 16th week.The amount of callus formed depends on the oxygen tension and strain pattern (treatment)

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REPARATIVE STAGE

Consolidation(lamellar bone deposition)Type II collagen is replaced by type I collagen.Followed by mineralization of the collagen. (osteoid)Enchondral ossification- formation of lamellar bone over hyaline cartilageBone substitution- formation of lamellar bone over woven bone.

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REMODELLING

Recycling of minerals (calcium and phosphate)Conversion of primary lamellar bone Secondary lamellar boneMay last upto 7 years

Osteoclast with their cutting cones

Resorbs the bone and form

howship

lacunae

Osteoblast then grows and lay down the lamellar bone

According to the functional load and stress(wolff’s law)

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FACTORS AFFECTING REMODELLING

Proximity to appendicular skeletonJuxta physeal deformity (more bone deposition on concave side and bone resorption at convex side). So any deformity near the physis have more chances of remodelingPresence of deformity near the particular physis. Remodeling is more when present near proximal humerus than distal humerus.

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FACTORS AFFECTING REMODELLING

Fracture location- fracture near the metaphysis remodels faster.Age of the patientPathological bone

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FACTORS AFFECTING FRACTURE REPAIR

Method of treatment

Affect of age and site of fracture

Absolute stability, rigid fixation, low strain environment

Primary fracture repair

Fracture heals faster in children by 1.5 to 2 times than in old age

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FACTORS AFFECTING FRACTURE REPAIR

Smoking

Radiation

can causeOsteoradionecrosisFracturesBone growth changesRadiation induced cancers

smoking

Osteoblastic activity

inhibits

osteoporosis

induces

Estrogen activity

Inhibits

Antioxidant properties of vitamin C and E

inhibits

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BONE GRAFT AND BONE GRAFT SUBSTITUTE

Indications

-

Skeletal defects after tumor resection

Reconstruction of bone defects after failed joint arthroplasty

Reconstruction of congenital bone defects

Obliteration of cystic cavity of bone

Repair of fresh fractures with bone loss.

Treatment of non union

Arthrodesis of joints.

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BONE GRAFT AND BONE GRAFT SUBSTITUTE

Provide

Latticework for ingrowth of host bone-

osteoconductive

Supply living osteogenic cells-

osteogenic property

Growth factors to induce bone formation-

osteoinduction

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BONE GRAFT AND BONE GRAFT SUBSTITUTE

Types of graft-

Cancellous graft

Cortical graft

Cortico

- cancellous graft

Auto graft

Syngraft

Allograft

Xenograft

Synthetic graft

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BONE GRAFT AND BONE GRAFT SUBSTITUTE

Sites of obtaining cancellous bone auto graft

Iliac crest

Proximal tibia

Trochanteric region of femur

Distal condyle of femur

Olecranon process of ulna

Distal radius styloid process.

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BONE GRAFT AND BONE GRAFT SUBSTITUTE

Sites for obtaining cortical bone auto graft

Fibula

Tibia proximal half

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BONE GRAFT AND BONE GRAFT SUBSTITUTE

Types of allograft-

Fresh

Fresh frozen

Freeze dried (lyophilized)

Osteochondral

allograft

Large composite graft

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