Week 2 - fractures and dislocations Flashcards
Define a fracture. (LO1)
“A fracture is described as a disruption in the continuity of all or part of the cortex of the bone.”
What are the different types of fractures relating to cause? (LO1)
- traumatic (acute)
- insufficiency
- stress
- avulsion
How do traumatic fractures occur? (LO1)
Generally the result of a sudden incident/impact that results in damage to the bone, e.g. sport or road traffic accidents.
How do insufficiency fractures occur? (LO1)
Result from a normal load on an “insufficient” bone, e.g. osteoporosis.
How do stress fractures occur? (LO1)
Due to a reasonable action repeated excessively resulting in abnormal stress on the bone, e.g. excessive marching in army personnel.
How do avulsion fractures occur? (LO1)
Result from a trauma to a ligament or tendon and usually occur in young athletic people.
What is the standard way to confirm a clinical diagnosis of a suspected fracture? (LO1)
X-ray
Some fractures may not be visible on an X-ray (particularly stress fractures), what are some indirect signs of a possible fracture? (LO1)
- The disappearance of normal fat stripes and fascial planes.
- Joint effusions.
- Periosteal reactions.
- New periosteal bone formation (faint white addition at the fracture site on x-ray).
What are the rules associated with taking an x-ray? (LO1)
- A minimum of 2 planes of view is necessary, 4 for scaphoid fracture.
- If multiple injuries are suspected or trauma has occurred, the field of view should be expanded in order to accommodate these.
Why do fractures become more visible with time before healing? (LO1)
Osteoclasts resorp the dead bone at the edge of the fracture site making the gap wider.
Which parts of the body would you not x-ray? (LO1)
- Ribs - make a clinical diagnosis, an x-ray won’t help you.
- Nose - mostly cartilage so won’t be able to see much.
- Coccyx - some point forwards, downwards, backwards, you might just be able to see the fracture.
N.B. if there is pain at the end of expiration (suspected pneumothorax), then x-ray of ribs is warranted.
What is meant by lucent lines on a fracture x-ray? (LO1)
A dark line indicating the fracture.
What do the different colours on an x-ray indicate? (LO1)
Black = air Dark grey = fat Light grey = water White = bone White stripe = epidermis
What is the rule regarding ring fractures? (LO1)
A rigid ring must break in at least 2 places so if you find one fracture, find another.
e.g. pelvis
What is the rule regarding paired bone fractures? (LO1)
If only one bone in paired bones is fractured, x-ray the joint above and below as there must be a dislocation/ligament disruption.
e. g. tibia/fibula
e. g. facial bones: maxilla, zygomatic, lacrimal, nasal (would take an additional x-ray of the neck in this case)
e. g. radius/ulna
What are the different categories to describe a fracture clinically? (LO1)
- Position.
- Path of fracture line.
- Simple or comminuted.
- Joint involvement.
- Closed or open (compound).
How would we further subcategorise the position of a fracture? (LO1)
- Angulation.
- Displacement.
- Distraction.
- Impaction.
- Rotation.
- Foreshortening.
How would we describe the angulation of a fracture? (LO1)
The degree of the angle, e.g. 45 degrees, followed by:
- Valgus - fracture ends of the bone pointing medially.
- Varus - fracture ends of the bone pointing laterally.
- Posterior - fracture ends of the bone pointing posteriorly.
- Anterior - fracture ends of the bone pointing anteriorly.
How would we describe the displacement of the bone as a result of the fracture? (LO1)
- Laterally displaced - away from the plane of the body.
- Medially displaced - towards the plane of the body.
Describe what is meant by distracted and impacted fractures. (LO1)
Distracted: two ends of the bone (from the fracture site), have been pulled away from each other.
Impacted: two ends of the bone have been crushed together at the fracture site.
Describe what is meant by rotation with regards to a fracture? (LO1)
- Medially rotated = the mobile fragment of bone is internally rotated.
- Laterally rotated = the mobile fragment of bone is externally rotated.
Describe what is meant by foreshortening of the bone in a fracture? (LO1)
This is when the bone fragments are completely misaligned, with one of the fragments moving so the ends of the two fragments overlap, visibly shortening the bone.
What are the four different paths of a fracture line? (LO1)
- Transverse (most stable) - horizontal line through the shaft.
- Oblique - diagonally through the shaft.
- Spiral - spiralling through the shaft.
- Longitudinal (least stable) - vertical along the axis of the bone.
If a fracture results in more than 2 fragments of bone, what is it referred to as? (LO1)
Comminuted fracture.
What are the types of joint involvement in a fracture and how could they impact the patient long-term? (LO1)
- Dislocation - adjoining bones no longer touching each other.
- Subluxation - minor/incomplete dislocation where joint surfaces still touch but are not in normal relation to each other.
Joint involvement can mean damage to the cartilage leading to premature osteoarthritis later in life.
Describe what is meant by open (compound) and closed fractures? (LO1)
If the skin is unbroken, it is a closed fracture.
If a piece of bone is in contact with air, it’s a compound fracture (open).
What is a Colles fracture? (LO1)
A fracture of the distal radius resulting in a posterior displacement of the radius and obvious deformity.
What are the different types of fractures in children? (LO1)
- Plastic.
- Torus.
- Greenstick.
- Growth plate fractures.
- Non-accidental injury.
What is a Greenstick fracture? (LO1)
Children’s bones have a degree of elasticity but when bent too far, one side (the side being stretched) may crack slightly, causing a Greenstick fracture.
What is a Torus (buckle) fracture? (LO1)
“An incomplete fracture of the shaft of a long bone that is characterised by the bulging of the cortex.”
As children’s bones have a degree of elasticity, instead of a crack on the side being stretched (Greenstick), the opposite side pushes out some of the bone, creating a bulge.
What is a plastic (bowing) fracture? (LO1)
As children’s bones have a degree of elasticity, when a longitudinal force is applied. If the force is low and subsequently released, the bone will return to its normal position.
If the force is greater than the mechanical strength of the bone, the bone undergoes plastic deformation and when the force is released, the bone remains in this bowed position.
Although no fractures are visible radiographically, microscopic fractures occur on the concave border of the bowed bone.
What are the different types of growth plate fractures? (LO1)
We use the Salter-Harris classification for this: S - slipped (type I) - best case A - above (type II) L - lower (type III) T - through (type IV) R - ruined (type V) - worse case
Describe what is meant by a Salter-Harris type I fracture (slipped). (LO1)
Horizontal along and through the growth plate, not involving bone.
Describe what is meant by a Salter-Harris type II fracture (above). (LO1)
Through the growth plate and metaphysis (most common).
Describe what is meant by a Salter-Harris type III fracture (lower). (LO1)
Through the growth plate and epiphysis.
Describe what is meant by Salter-Harris type IV fracture (through). (LO1)
Throught the metaphysis, growth plate and the epiphysis.
Describe what is meant by Salter-Harris type V fracture (ruined). (LO1)
Crush injury of the epiphyseal growth plate (worse prognosis).
Bonus question: why is a metaphyseal corner fracture a sign of abuse? (LO1)
The only way to obtain this fracture is to grab a child by the arm and swing them around your head.
How do pathological fractures occur? (LO1)
This is due to focally abnormal bone.
E.g. myeloma eating away at bone.
E.g. metastatic cancer.
What are the two examples of fracture mimics? (LO1)
- Unfused epiphyseal growth plate.
- Unfused apophysis (ossification centre where the tendon inserts).
What are the factors determining fracture healing? (LO1)
- age
- fracture site
- position of fracture fragments (e.g. comminuted).
- blood supply to fracture site.
- immobilisation of the fracture.
- other conditions, e.g. osteoporosis.
How does healing of a fracture take place? (LO1)
- The osteoclasts will remove damaged bone which may result in widening of the fracture line.
- Endosteal healing in stable fractures will result in the obliteration of the fracture line after several weeks.
- In less stable fractures, periosteal healing results in the formation of a callus manifesting as a white mass around the fracture site.
What are the types of complications which can occur during healing of a fracture? (LO1)
- Delayed union.
- Malunion.
- Nonunion.
- Damage to blood supply or nerves.
- Damage to surrounding tissues.
What is meant by delayed union? (LO1)
When the fracture does not heal in the expected time.
Usually with further immobilisation, the fracture will heal.
What is meant by malunion? (LO1)
When the fracture heals in a manner that is unacceptable.
This could be cosmetically or mechanically.
What is meant by nonunion? (LO1)
When it is determined that a fracture will never heal on its own.
This can present as sclerotic fracture margins (thickening of the bone). Pseudoarthritis (lack of bone fusion) may occur along with a synovial lining (connective tissue).
What must happen if it’s suspected that a fracture could be compromising blood supply? (LO1)
The fracture must be reduced before any imaging is done to preserve function and prevent long term damage.
Define compartment syndrome. (LO2)
Increased pressure within an osteofascial compartment leading to compromised perfusion of the tissue. If left untreated, necrosis can occur within hours.
Describe acute and chronic compartment syndrome. (LO2)
Acute compartment syndrome is a medical emergency, usually caused by trauma, i.e. broken leg.
Chronic/exertion compartment syndrome is caused by intensive repetitive exercise and usually pain is alleviated when exercise stops and the limb rests.
Describe the epidemiology of compartment syndrome. (LO2)
- Most cases occur after a trauma.
- 75% of acute cases are associated with fractures.
- Tibial shaft fracture is the most common cause of acute cases, associated with 1-10% of incidence rates.
- Soft tissue injuries is the second most common cause of acute cases.
- Other causes include: burns, vascular injuries, crush injuries, drug overdoses, thrombosis, infections, penetrating trauma, improperly placed casts or splints, poor positioning during surgery, etc.
Describe the presentation of compartment syndrome. (LO2)
- Tense or “wood-like” feeling of the compartment.
- Pain is severe and out of proportion to the injury.
- Initially pain may be burning sensation or deep ache.
- Paraesthesia, hypoaesthesia or poorly localised deep muscular pain may also be present.
- Late findings: the 5 Ps
- Pain
- Pulselessness
- Paraesthesia
- Paralysis
- Pallor
Describe the investigations for compartment syndrome. (LO2)
- Skin: look for lesions, swelling or colour change.
- Palpate: the compartment, note temperature, tension, tenderness.
- Check pulses.
- Weber two-point discrimination test for sensation - evaluate how finely innervated the skin is.
- Evaluate motor function of the affected limb.
- Radiographs if fracture is suspected.
- Manometer to measure intracompartmental pressure if uncertain (does this by measuring resistance to saline solution when injected into the compartment).
- Slit catheter place within compartment, pressure measured with arterial line transducer (continuous monitoring and more accurate).
- Normal pressure 0-8mmHg.
- Pressure >30mmHg = compartment syndrome.
- Delta pressure (perfusion pressure) = diastolic pressure - measured intracompartmental pressure.
- Ultrasound with Doppler to look for occlusion or thrombus.
- Blood cound and coagulation (pre-operative).
- Creatinine phosphokinase (CPK) levels show muscle breakdown from from ischaemia, damage, or rhabdomyolysis.
- If rhabdomyolysis, do renal function tests, urin myoglobin and urinalysis (full chemistry panel).
Describe the management for compartment syndrome. (LO2)
- Fasciotomy.
- Immediate surgical consult.
- Provide supplemental oxygen.
- Relieve pressure - remove any restrictive casts, dressings or bandages.
- Keep extremity at the level of the heart to prevent hypo-perfusion.
- Prevent hypotension and provide blood pressure support in patients with hypotension.
Define dislocation. (LO3)
Absence of articulation between two bones.
What are the most common dislocations? (LO3)
- Anterior glenohumeral dislocations.
- Acromioclavicular subluxations and dislocations.
- Hip dislocations.
- Knee dislocations.
- Ankle sprains.
What are key questions to ask in a trauma history? (LO3)
Use the AMPLE mnemonic: A - allergies M - medications P - past medical history L - last meal E - events
Fully medical history if time allows.
In what direction does the shoulder commonly dislocate and what complications could this present? (LO3)
Anterior - this moves the humeral head towards the axilla and might damage the neurovascular bundle running there.
Shoulder dislocations are more common in men and may require surgery if recurrent.
List the key things that need to be considered alongside a shoulder dislocation. (LO3)
The nerves and vascular supply.
- Assess for nerves because the humeral head (shoulder dislocation) can move to the area of the nerves during a dislocation.
- Assess for the motor and sensory function of the medial nerve.
List the key finding when examining a patient susceptible to recurrent shoulder dislocations. (LO3)
Patients with recurrent shoulder dislocations will have joint instability - on certain movements, the patient will experience the sensation when they are about to dislocate the joint.
When this happens, they will stop the examination or move their arm away.
What does the median nerve innervate? (LO3)
The median nerve innervates the palm of the hand (thumb, index, middle and half of the ring finger) and the adductor pollicis brevis.
How do we test median nerve function? (LO3)
Place the hand with the palm facing up. The thumb must also be facing up. Push down on the thumb and if the patient is able to resist it, the median nerve is functioning normally.
What does the radial nerve innervate? (LO3)
The radial nerve innervates the posterior aspect of the arm, from the upper arm all the way down to the back of the hand and fingers. It also innervates the extensor muscles in the forearm.
How do we test radial nerve function? (LO3)
Ask the patient to extend the wrist and fingers while you push against them. If the patient is able to resist it, the radial nerve is functioning normally.
What does the axillary nerve innervate? (LO3)
The axillary nerve innervates the deltoid muscle and provides sensation over the shoulder.
How do we test axillary nerve function? (LO3)
Ask the patient to abduct their arm from the shoulder joint. If they can lift it up past 90 degrees, axillary nerve is functioning normally.
What does the ulnar nerve innervate? (LO3)
The ulnar nerve innervates the pinky finger and the medial half of the ring finger. It also innervates some muscles in the flexor compartment of the forearm (flexor capri ulnaris and part of the flexor digitorum profundus).
How do we test ulnar nerve function? (LO3)
Ask patient to flex their wrist while you provide an opposing force. If they are able to resist, the ulnar nerve is functioning normally.
Alternately, ask the patient to adduct their pinky.
How do you confirm a diagnosis of a fracture/dislocation? (LO3)
X-ray can identify the main issue.
CT/MRI can identify the underlying cause and associated soft tissue injuries.
List the 4 key principles of fracture management. (LO3 + LO5)
Follow the 4 Rs:
Resuscitate - life-saving treatment if the patient is dying.
Reduce - put bone back in its anatomical position (closed vs open).
Retain - maintain bone in the reduced position - with sling/cast/plates, etc.
Rehabilitation - movement to aid recovery and reduce future risk of osteoarthritis.
Describe the pharmacological management of a fracture. (LO3)
- Analgesia.
- If pain is severe, might require opioids, e.g. morphine.
- If pathological fracture, treat the underlying condition, e.g. for osteoporosis - calcium and vitamin D, bisphosphonates and glucosamine.
Why is it important to assess neurovascular status when dealing with a fracture? (LO3)
Bony injuries can damage the surrounding structures, e.g. nerves and blood vessels. This can have long-term effects if not managed promptly. This also helps determine the severity of fractures and further management.
List the 2 most common wrist fractures? (LO3)
Colle’s fracture - outwards
Smiths fracture - inwards
Colle’s fracture occurs during a fall on outstretched hand (FOOSH).
How long do wrist fractures need to be in a cast (LO3)
4-6 weeks
What type of fracture is associated with dangling? (LO3)
Distal humerus fracture, sometimes along with damage to the olecranon.
It’s important to note that the ulnar nerve runs near this area and may be damaged.
Which way does the hip most commonly dislocate? (LO3)
Posteriorly, which can affect the sciatic nerve.
What are the clinical findings in a hip fracture? (LO3)
The leg is shortened and externally rotated.
What type of hip fracture can cause avascular necrosis of the femoral head? (LO3)
Intracapsular/sub-capital
Which way does the knee most commonly dislocate? (LO3)
Laterally - the patella slides sideways after impact injuries. These can spontaneously reduce when the knee straightens.
How is a muscle sprain managed? (LO3)
Use the RICE mnemonic: R - rest I - ice C - compression E - elevation
What is the movement that causes ankle sprains. (LO3)
Excessive inversion or eversion of the ankle.
How can we check for sufficient blood supply in the limbs? (LO3)
In a normal limb:
- Capillary refill is <2 seconds.
- Pulses present and normal.
- No cyanosis.
Capillary refill - squeeze the tip of the finger and let go. Refill time is how long it takes for the tip to turn oink again from blood re-entering.
Describe the 3 different levels of energy that can cause injury to a joint. (LO3)
- Low energy - ankle sprain.
- High energy - accident during collision sports.
- Extreme energy - road traffic accidents.
List the 5 different types of imaging used to image bone. (LO4)
- Plain x-rays.
- Magnetic resonance imaging (MRI).
- Ultrasonography.
- Computed tomography (CT).
- Nuclear medicine.
Briefly describe x-rays. (LO4)
X-rays produce images that show structural changes and help to monitor bone and joint diseases.
List some advantages of using X-rays to image bone. (LO4)
- Useful for osteoarthritis.
- They are non-invasive.
- Can be used for guidance whilst inserting catheters.
- Can also show up issues that weren’t the initial reason for the imaging.
- Can be used on a wide range of people.
List some disadvantages of using X-rays to image bone. (LO4)
- Some features of osteoarthritis such as erosions only show up with time so can’t be seen on an initial x-ray.
- Poor images of soft tissues.
- The radiation can be harmful.
- There’s a limit to the number of x-rays you can have in a given period of time due to radiation.
Briefly describe magnetic resonance imaging (MRI). (LO4)
MRIs use strong magnetic field gradients and radio waves to generate images of the organs in the body.
List some advantages of using MRIs. (LO4)
- There is enough good soft tissue discrimination to show tumours, inflammation and degeneration.
List some disadvantages of using MRIs. (LO4)
- Expensive.
- The patient may feel claustrophobic.
- The loud noise may make the patient uncomfortable.
Briefly describe ultrasonography. (LO4)
Ultrasonography uses high-frequency sound-waves in order to image internal bodily structures.
List some advantages of using ultrasonography. (LO4)
- Cheap.
- No ionising radiation.
- Good for superficial anatomy.
- Good for investigation into small joint synovitis and erosions.
List some disadvantages of using ultrasonography. (LO4)
- Lower resolution when looking at deeper parts of the body.
- Don’t show structure inside the joint.
Briefly describe computed tomography (CT). (LO4)
CT uses x-rays and a computer to image inside the body.