Skeletal Pathology

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Fractures

Fractures are the most common skeletal abnormality seen in general radiology.

A fracture usually appears as a radiolucent line crossing the bone and disrupting the cortical margins.

Fractures in which bone fragments overlap produce a radiopaque line.

There are two major causes of fractures in the skeletal system:

1. Traumatic

2. Pathological

In all cases of trauma, it is essential to produce two x-rays of the injured part 90 degrees from each other to determine displacement or fracture continuity.

Types of Fractures

•A closed fracture , also called a simple fracture, is a broken bone that does not penetrate the skin.

•An open fracture, also called a compound fracture, is an injury where a broken bone is open through the skin. When a broken bone penetrates the skin there is a need for more immediate treatment, and an operation is often required to clean the area of the fracture.

Open fractures usually take longer to heal because of the extent of injury to the bone and the surrounding soft-tissues. Open fractures also have a high rate of complications including infection and non-union.

Classifications (types) of fractures

Complete fractures involve the entire cross section of the bone resulting in the discontinuity of two or more fragments.

Incomplete fractures are fractures that crack the bone, but the fracture does not completely traverse the width of the affected bone.

Longitudinal fracture one extending along the length of the bone.

Linear fracture, a fracture that extends parallel to the long axis of a bone but does not displace the bone tissue. Sometimes called a hairline fracture.

Classification(types)of Fractures

Fractures are classified by their : direction, position, # of fracture lines and the integrity of the overlying skin.

Transverse Fracture of the surgical neck of the humerus (complete)

Spiral Fracture

 

Spiral Fracture

 

Avulsion Fracture

 

Greenstick Fracture (Incomplete fracture with opposite cortex intact)

A Torus (buckle) Fracture (incomplete)

Comminuted and Compound

 

Compression fracture

•Associated with osteoporosis or with a compression force from trauma.

•Radiographically shows collapse of a vertebral body which results in decreased length or width of the bone. (wedge shaped)

Impacted fractures

Impacted Fracture : An impacted fracture is similar to a compression fracture. It is a closed fracture which occurs when pressure is applied to both ends of the bone, causing it to split into two fragments that jam into each other. This type of fracture is common in car accidents and falls.

Depressed fractures

•Occurs in the skull or tibial plateaus (usually comminuted fracture)

 

Classification of fractures

Undisplaced fracture is a bone break in which cracks in the bone may radiate in several directions but the bone fragments do not separate.

Displaced fracture – fracture in which the two ends of the broken bone are separated from one another

Dislocation– displacement of a body part, especially the temporary displacement of a bone from its normal position.

Subluxation– incomplete or partial dislocation of a bone in a joint

 

Dislocated Hips

•Posterior dislocations of the hip (85-90%) are far more common than anterior dislocations.

Dislocation of the shoulder

The shoulder is the most commonly dislocated joint in the body. About 95% of shoulder dislocations are anterior

 

Common ( specifically “Named “) Fractures

•Sides 20 – 42 are common fractures and dislocations seen in general radiography and are a requirement of the CAMRT.

•Not all of these fractures are in Eisenberg.

 

Bimalleolar (Pott’s Fracture)

Bimalleolar fracture of ankle is a fracture of the lower fibula and of the malleolus of the tibia, resulting in displacement of the foot. Image shows: A transverse fracture of the medial malleolus (broad arrow) is associated with a low oblique fracture of the distal fibula (thin arrow).

Trimalleolar

A trimalleolar fracture is a fracture of the ankle that involves the lateral malleolus, medial malleolus and the distal posterior aspect of the tibia, which can be termed the posterior malleolus.

 

 

Blow out Fracture

Blow-out fractures are produced by a traumatic force. The force is absorbed by the orbital rim and transmitted to the weaker medial orbital wall or floor causing a fracture. As the intraorbital pressure is raised by the backward displacement of the eye, periorbital fat is squeezed out of the orbit, blowing the fractured floor out into the maxillary sinus.

Boxers Fracture

A boxer’s fracture involves a transverse break in the neck of the 5th metacarpal with palmar angulation. Cause: blow struck with clenched fist.

 

 

Boxer’s Fracture

 

Bennett’s Fracture

A fracture at the base of the first metacarpal bone. The fracture line enters the carpometacarpal joint, complicated by subluxation or dislocation

With subluxation the smaller fracture fragment stays attached to the wrist bones and the larger fragment is displaced along with the whole thumb.

Cause- fall or force to a partially flexed thumb

Patients present with swelling and pain at the base of the thumb

 

Colles’ Fracture

Most common fracture of the wrist.

A fracture of the distal radius with the distal fragment being displaced posteriorly.

Caused by falling on outstretched hand

 

Smith’s Fracture (reverse Colles’)

A fracture of the wrist with the distal fragment of the radius displaced anteriorly rather than posteriorly as in a Colles’ fracture.

Usually the result of falling backwards on an outstretched arm.

Intertrochanteric Fracture

•An intertrochanteric fracture is one where the fracture line lies between the greater and lesser trochanters. Unlike a femoral neck fracture, the intertrochanteric region has good blood supply to cancellous bone, and thus has good healing potential.

Contracoup Fractures

•A fracture in a part or region opposite to that at which the blow is received.

Example: Mandible fracture

Example: Tibia fractures- an impact to the distal tibia may create a fracture thru the fibular head (proximal)

Stress Fractures

Stress fracture also known as a march or fatigue fracture. Fracture is the response of the bone to repeated stresses, none of which is sufficient to cause a fracture.

Epiphyseal Fractures(Salter- Harris system)

•Epiphyseal fractures is a fracture through the epiphyseal plate. This is one of the most easily fractured sites in the long bones of children. Radiologists use the Salter-Harris classification to describe the severity .

 

Salter-Harris Classification of Epiphyseal fractures

Type IV                    Type III

Slipped Capital Epiphysis

Monteggia’s Fracture

Fracture of the proximal half of the ulna, along with dislocation of the radial head.

Monteggia’s Fracture

Supracondylar Fractures

•Supracondylar fractures of the humerus are widely considered to be the most common fracture of the elbow in children.

•Approximately 3 percent of all fractures in children are supracondylar fractures.

•They often result from trauma to the elbow, most often due to a fall from a height or related to sports or leisure activities.

Supracondylar Fracture-Fat pad sign

Navicular (Scaphoid) Fracture

Hangman’ Fracture

•This fracture occurs through the pedicles of the axis (C2), with or without displacement of C2 or C3

Hangman’s Fracture

 

 

 

Examples of fractures

•Slides 42-47 are not on the CAMRT profile but are good examples of the different types of fractures.

Example of a transverse fracture and normal ossification

Avulsion fractures of the spinous process of C6 -Clay-shoveler’s fracture

Fracture of the body of C7- initially missed on first x-ray

Dislocation of the Atlantooccipital joint

A. Transverse fracture of the odontoid(dens) of C2. B. Fracture of the body of C2

Fractures from seat belts

Pathological Fracture

Fractures that occur in bone that has been weakened by disease.

Battered-Child Syndrome

•Physical child abuse or non-accidental child trauma refers to fractures and other signs of injury that occur when a child is hurt by the parents or guardians.

• This syndrome referred to many fractures that occurred at different times in children too young to have received them from an accident.

•Radiographic appearance of this syndrome include: multiple fractures at varying stages of healing, corner fractures, rib fractures, diaphyseal fractures, and skull fractures.

Battered Child Syndrome

A. Demonstrates a corner fracture. B. Demonstrates healing displaced fracture

Battered Child Syndrome-Bucket Handle Fracture – avulsion fracture of the metaphyseal plate.

Battered Child Syndrome

Nuclear Medicine scan reveals multiple hot spots

Fracture Healing

•Fracture – broken periosteum and blood vessels

•Hematoma plugs up the gap between the bone fragments

•New capillaries will start to grow “procallus”

•Phagocytic cells clean up debris.

•Fibroblasts produce collagen within the procallus.

•Chondroblasts produce fibrocartilage, now procallus is called “fibrocartilaginous callus.”

Fracture Healing

•Fibrocartilaginous callus last approx. 3 weeks.

•Osteoblasts from neighboring healthy bone will begin to produce trabecullae.

•Trabecullae infiltrate fibrocartilagous callus to create a bony callus.

•Remodeling by osteoblasts and osteoclasts to create proper cancellous and compact bone structures.

•It can take 3 – 4 months for the new bone to resemble original bone.

Fracture Repair

Post fracture Treatment

Closed reduction (external reduction or external fixation)-is a non surgical procedure. Fractures are realigned by manipulation and are immobilized by a cast or splint.

Open reduction (internal fixation) ORIF– a surgical procedure is required. The fracture site is exposed and screws, plates, rods and wires are installed as needed to maintain alignment until new bone growth can take place.

Closed Reduction

Bimalleolar Fracture

ORIF-Open reduction with internal fixation

Extensive callus formation around fracture site.

Also note area where medullary rod was placed is also seen.

K wires in hands

Malunion of fracture

•Poor positioning of fracture will result in deformity and possibly decrease function/loss of use.

Non union of Scaphoid

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