Session 4: Disorders of the Knee Flashcards
What is this?

A femoral shaft fracture of the left femur.
Mechanism of fracture from femoral shaft fracture in previously healthy children and adults.
High-velocity trauma like falls from a heigh and road traffic collosions.
In young children think of child-abuse as well.
Mechanism of fracture of femoral shaft fracture in elderly patients.
Since they be osteoporotic, have bone lesions, bone metastases their femur can be more prone to fracture.
This means that a low-velocity injury can cause a fracture like falling over from a standing position.
How do patients clinically present with a femoral shaft fracture?
Proximal fragment often abducted + flexed.
Distal fragment usually adducted into a varus deformity + extended.
The patient will have a tense swollen thigh and pain.
What is particularly important to consider in a patient with a femoral shaft fracture?
There will be a large amount of blood loss which can be up to 1000-1500 ml meaning the patient can develop hypovolaemic shock.
Treatment of femoral shaft fracture.
Treated with surgical fixation.
Why is the proximal part of the femur abducted and flexed in femoral shaft fracture?
The pull of gluteus medius and minimus on the greater trochanter will abduct the proximal femur. The iliopsoas will flex it.
Why is the distal part of the femur adducted and extended in a femoral shaft fracture?
Adductor magnus and gracilis adduct the distal femur.
Gastrocnemius will extend the distal femur.
What is this?

A distal femoral fracture
Mechanism of injury in distal femoral fracture of young patients.
In elderly.
High-energy sporting injury.
In elderly commonly associated with osteoporosis and fall from standing.
Important structure to consider in distal femoral fracture.
The popliteal artery and careful assessment of the neurovascular status of the limb before and after.
What is this?

Tibial plateau fracture.
What are tibial plateau fractures?
Which kinds are there?
Which is the most common?
Fracture affecting the articulating surface of the tibia within the knee joint. They can be unicondylar meaning they affect on condyle but also bycondylar meaning they will affect both tibial condyles.
Lateral tibial condyle fracture is most common.
Tibial plateau fractures can also be associated with menisci tear and ACL injuries.
Mechanism of injury in tibial plateau fracture.
High-energy injuries where the usual mechanism is axial loading with varus or valgus angulation meaning there is an abnormal medial or lateral flexion load of the knee.
Common complication of tibial plateau fracture.
Post-traumatic osteoarthritis since the articular cartilage is always damaged.
What is this?

Patellar fracture
Mechanism of injury of patellar fracture.
Most commonly occur in patients aged 20-50 years.
Direct impact injury onto the patella.
Eccentric contraction of the quadriceps.
How will the patient clinically present with a patellar fracture?
Often a palpable defect in the patella and a haemarthrosis.
Unable to perform a straight leg raise meaning lifting the leg off the bed by flexing at the hip and keeping the knee extended.
Being unable to perform a straight leg raise is not always a problem in patellar fracture.
How come sometimes it is a problem, and sometimes it is not?
It depends on if the patella has been displaced distally to the insertion of the quadriceps tendon.
If it has quadriceps muscles won’t be able to extend the knee.
Treatment of displaced patellar fracture.
Treament of non-displaced patellar fracture.
Displaced: surgical fixation and reduction.
Non-displaced: protected while healing takes it natural course by the use of splinting and using crutches.
What is subluxation?
Partial displacement.
In what direction is it most common for the patella to dislocate?
Why?
Laterally due to the Q-angle between the line of pull of the quadriceps tendon and the patellar ligament.
VMO keeps the patella from dislocating laterally however. VMO stabilise the patella within the trochlear grove.
What is this?

Lateral dislocation of the patella.
Common mechanism of injury of patellar dislocation + age group.
Trauma like twisting injury in slight flexion.
Usually athletic-teenagers internally rotating their femur on a planted foot whilst flexing the knee.



