Bone Fracture and healing

Bone Fracture and healing Prof. MamounKremli AlMaarefa College

Definition of Fracture • A break in the continuity bone • Often associated with soft tissue injury • Soft tissue injuries might be more serious than the fracture

Etiology • Motor Vehicle Accident • Fall • Sport injuries • Vigorous Exercise • Bone Diseases • Osteoporosis • Osteomyelitis • Cyst, …

Types of Fracture • Ordinary • Caused by a force • Normal bone • Pathological • Caused by trivial force • Diseased (weak) bone

Types of Fracture • Ordinary • Caused by a force • Normal bone • Pathological • Caused by trivial force • Diseased (weak) bone • Osteoporosis • Osteomyelitis • Tumour, cyst, ..

Types of Fracture www.childrensmemorial.org/ www.childrensmemorial.org/ • Incomplete • Fracture line is incomplete • Only one cortex is broken • Complete • Fracture line is complete • Bothe cortices are broken

Types of Fracture • Incomplete • Green-stick • One cortex is broken • Other cortex is bent • In children Lee P et al. Radiographics 2004;24:1009-1027

Types of Fracture • Complete • Simple: • One fracture line • Two bone fragments • Comminuted: • More than one fracture line • More than two bone fragments • More soft tissue injuries

Types of Fracture • Complete • Simple: • Hairline (Fissure) • In repeated stress • e.g. march fracture in metatarsals • Transverse • Oblique • Spiral

Types of Fracture • Complete • Comminuted: • Butterfly • Segmental • Multiple fragments • Compression

Types of Fracture • Undisplaced • Normal alignment maintained • Displaced • Deformed from normal alignment

Types of Fracture • Closed • Skin intact • Compound (Open) • Skin not intact • Communicating to outside

Types of long bone fractures • Metaphyseal • Diapyseal • Articular • Epiphyseal (children)

Sign and Symptoms of Fracture Pain Swelling Deformity Local tenderness Loss of function

Diagnostic Evaluation • X-ray • The most useful • MRI, CT-scan • In suspected cases • In intra-articular fractures

Fracture Healing • Stages of fracture healing: • Hematoma • Inflammation • Repair • Remodeling

1. Hematoma • Bleeding caused by vessel rupture • Hematoma collects • Bone at fracture edges dies Rockwood and Green

2. Inflammation Inflammatory cells accumulate Inflammatory mediators (cytokines) New blood vessels proliferate Rockwood and Green

2. Inflammation • Mesenchymal cells accumulate • After 1 week forms granulation tissue • Osteoclasts remove necrotic bone at fragment ends • growth factors stimulate the proliferation and differentiation of mesenchymal stem cells • Formation of connective tissue

3. Repair • Connective tissue differentiates • Cartilage and fibrous tissue form • Soft callus formation (2-3 weeks) • Movement at fracture stimulates more callus Rockwood and Green

3. Repair - Tissue Differentiation connective tissue granulation tissue Giemsa stain

3. Repair • Vascular and cellular response leads to tissue differentiation and mineralization resulting in restoration of mechanical integrity • Fibrocartilage mineralizes (converts callus to woven bone)

Tissue Differentiation Cascade Masson-Goldner Cartilageformation Mineral deposition Bone

Callus Formation • Periosteal callus • forms along the periphery of the fracture site • Intramedullary callus • forms in the center of the fracture site • Endochondral ossification at the site of the fracture hematoma • Chemical and mechanical factors stimulate callus formation and mineralization

Callus Formation • Stability adequate in axial plane • Angulation can still occur • fracture ends linked together by soft callus • hard callus stage starts & lasts until fragment ends are firmly united by new bone (3-4 m) www.landesbioscience.com Rockwood and Green

4. Remodeling • Woven bone slowly replaced by lamellar bone (few months to years) • Medullary cavity is reconstituted • Bone is restructured in response to stress and strain

bony bridging Fracturehealing - summary • Inflammation • Hematoma • Mesenchymal cells • Soft callus • Granualationtissue • Fibro-cartilage • Hard callus • Intramembranous bone formation • Enchondral ossification • Remodeling

Fracture healing - summary Summary

Prerequisites for Bone Healing • Adequate blood supply • Adequate mechanical stability • If either is lost: • results in delay in bone healing or no healing occurs • Smoking causes delay in bone union or nonunion

Complications of fractures • Early: • Shock • Compartment syndrome • Fat embolism • Deep vein thrombosis, embolism • Infection • Delayed • Malunion • Delayed union / Nonunion

Complications of fractures • Shock • loss of blood • Fractured femur could bleed 2L easily • Fractured Pelvis could bleed 4L easily • Open fractures with vascular injuries • What is the normal blood volume? • How much bleeding could be tolerated?

Complications of fractures • Compartment syndrome • The compression of nerves, blood vessels, and muscle inside a closed body space (compartment) • Causes tissue death from lack of oxygenation due to the blood vessels being compressed by the raised pressure within the compartment • More common in Forearm and leg (why?)

Complications of fractures • Deep Vein Thrombosis, Embolism • Caused by • Increased pressure in compartment • Interrupted venous return • Hematoma

Complications of fractures • Infection: • More in open fractures • Depends on amount of contamination and tissue necrosis • Possible in closed fractures

Complications of fractures • Delayed • Malunion: deformity • Delayed union • Non-union

Management of fractures First aid: ABC Other injuries Cover wounds Bone immobilization Definitive treatment of fracture

Management of fractures • Assessment • Type, location and severity of fracture • Soft tissue damage • Age and health status of patient • Affection of other parts or organs

Management of fractures • Goals: • To regain and maintain correct position and alignment. • To regain the function of involved part. • To return the patient to usual activities in the shortest time and at the least expenses.

Definitive treatment of fractures • Conservative • Simple fractures • More in children • Operative • More complex fractures • Articular fractures • More in adults

Conservative - closed reduction • Is the most common non surgical method for managing a simple fracture. • Splints: • as upper extremity bones do not bear weight, splints may be sufficient to keep bone fragments in place.

Conservative - closed reduction • Casts : • A cast is an immobilizing device made up of layers of plaster or fiber glass. • Allows early mobility and reduces pain

Conservative - closed reduction • Traction: • Application of a pulling force to a part of the body • Uses a system of ropes, and weights to provide reduction, alignment and rest

Open reduction / internal fixation • Achieves perfect reduction • Permits early mobilization • It is often preferred for elderly patients who are susceptible complications of immobility • Best for adults and in intra-articular fractures • Uses pins, screws, rods, plates, .. • After bone union, the metal may be removed, depending on the location and type of fracture

Examples of internal fixation Screws Wires Nails

Open reduction, internal fixation Forearm fractures in adults (Plates)

Nail in Tibial Fractures Intramedullary Nail

Bone Fracture and healing