Injuries to bones and joints of the lower limb Flashcards
Define Fracture
A breach of the integrity of part or the whole of a bone
Define Subluxation
Partial separation of the articular surfaces of the joint
Define Dislocation
Complete separation of the articular surfaces of a joint
Define Fracture dislocation
A dislocation where there is also a fracture involving one or more of the articular surfaces of a joint
Define Sprain
Stretching of the joint capsule and ligaments of a joint, insufficient to produce subluxation or dislocation
Will normal energy against normal bone cause a fracture?
no
Will excess energy placed on a normal bone cause a fracture?
yes
Will normal energy on a weak bone cause a fracture?
yes
Name some clinical signs and symptoms of a fracture
- Pain
- Swelling
- Tenderness
- Brusing
- Deformity
- Crepitus
- Abnormal Movement
What can cause bone weakness?
- Osteoporosis
- Osteogenesis Imperfecta - brittle bone disease
- Secondary tumours - most common bone tumour, usually from lungs/breast/kidney
What are the two outstanding features of a general fracture?
Abnormal movement and deformity
Why does a fracture cause pain?
Bones do not have sensory nerves to sense pain but surrounding muscles and nerves are affected. Bones are also full of blood and increasing pressure of blood during bleeding within muscles can cause pain
Explain what happens in the muscle compartments after a fracture
Bleeding occurs, it spreads into tissues and pushes muscles away, increasing pressure within the fascial space.
What is a compound fracture?
Why is this serious?
A fracture where the skin has been breached -means infection is more likely.
Can be from within or from outside.
What is meant by fracture union
The joining of bones affected by a fracture
What is meant by delayed union?
Coming together of the bone takes longer than expected.
E.g. on x-ray see callous formation - see that bone is healing but it is delayed
What is fracture non-union
The bone does not unite.
No callous formation -
What is fracture mal-union
fracture unites in the wrong place
e.g. bones that are hard to immobilise such as clavicle/if patient walks on fracture…
How are fractures diagnosed?
- History/Exam
- X-Ray (standard)
- CAT - shows different planes of injury
- MRI
- US
- Bone scan
In which plane is an antero-posterior x-ray taken?
Sagittal plane
In which plane is a lateral x-ray taken?
Coronal plane
Why are CAT scans useful for fractures?
Enables visualisation of structures not viewed well on X-Ray, can see soft tissues aswell as bone to monitor healing etc
Why are MRI useful in fracture diagnosis?
- Allows visualisation of bone surface
- Fractures involving articular cartilage can be viewed
- Can see density of the bone - helpful to visualise avascular necrosis
- Can see fluid in the joint - indicates things are wrong
Why is Ultrasound useful in diagnosing fractures?
- Childrens bones are soft and fractures can be hard to see on X-Ray, US allows visualisation of these finer fractures in children
What do we need to be aware of in pelvis fractures?
- Blood loss from associated injuries - can be fatal
- Abdominal injuries
- Nerve injuries
Explain why pelvis fractures can lead to large blood loss?
External and internal iliac veins run very close to the pelvis, fractures can easily damage veins.
Veins are unable to contract as they do not contain elastic muscle fibres and so the patient can bleed out quickly.
Why is vascular injury more likely to be fatal than injury to an artery?
Arteries contain muscle and are elastic so can contract to stop/lessen bleeding, veins do not so a patient can bleed out very quickly if a fracture damages a vein
What abdominal organs can be damaged in pelvis fractures and why?
The bowel - less common - adheres to pelvis margin so can be damaged
more common - Bladder - Retropubic, attached to symphisis pubis
In males - Urethra as it passes under the pubic symphisis
What nerve injuries can pelvis fractures cause?
The sciatic nerve can be damaged in sacrum fractures or injuries to the sacroiliac joint
How is the ilium likely to be damaged?
Usually a lateral blow e.g. motorcyclists into side of cars, RTAs to the side, falls to the side
How are pubic ramus fractures likely to occur?
Occur mostly in the elderly - osteoporotic
Falls etc
What is an open book pelvis fracture?
Two sides of the pelvis fall apart due to disruption of the symphisis pubis.
Front + back injury, all stability is gone. SIJ is broken and so is pubis symphisis.
What is the significance of the pelvic ring?
We aim to maintain the pelvic ring in pelvic injury
The pelvic ring consists of the two sacroiliac joints and the symphisis pubis, maintaining these enables us to weight bear. Without one stability is decreased greatly.
How are intra-articular fractures likely to ocur?
Blow hits femur from the side - knocks femoral head through into pelvis (extreme)
Landing on legs during parachuting/jumping – force goes vertically and hits roof of acetabulum.
Must be restored completely to prevent arthritis
Why is the neck of femur vulnerable to fracture/problems?
The neck of femur and the force line is in between stress lines - (gravity and weight bearing lines)
Where does the neck of femur get its blood supply from?
Lateral and medial femoral circumflex arteries from the deep/profunda femoris, travel up through periosteum to supply neck and femoral head
What is the line between intra/extracapsular fracture?
Which is more likely to lead to avascular necrosis and non-union? Why?
Fractures within the capsule are more prone to avascular necrosis and non-union
Extracapsular fractures occur in bone with a better blood supply and more viable
How would the leg of a patient with a fractured neck of femur present and why?
The affected limb would be short and externally rotated
Psoas Major and gluteus muscles pull to shorten and externally rotate the leg
Why are younger patients more at risk of avascular necrosis in femur fractures?
The amount of force it takes to break the femur of a younger person is a lot more than the force needed to break an elderly persons so a greater risk of avascular necrosis.
How can posterior hip dislocations occur?
Why must they be treated quickly?
What nerve(s) are at risk?
Force onwards onto a flexed knee e.g. passengers in car accidents
Must be treated within 6 hours to replace femoral head or patient is at risk of chondrolysis (death of articular cartilage)
Sciatic nerve is at risk of damage
How does damage to the menisci occur?
Rotation of the femur on a fixed tibia
(foot must be fixed on the ground for meniscal injury to occur)
How do you test the integrity of the cruciate ligaments?
Anterior draw test - Excessive move forwards = anterior injury
vice versa for posterior
How are cruciate ligament injuries treated?
The semitendinosus tendon can be used or a piece of patella tendon
What are tibial shaft fractures caused by?
Direct trauma
Rotational strain
How do we treat tibial shaft fractures?
External mobilisation - plaster cast
Internal immobilisation - pins
How do we diagnose achilles tendon rupture?
Positive Simmond’s test
Ultrasound
