Lower limb problems II Flashcards
Femoral shaft fracture is often due to
High energy injuries
Investigations for femoral shaft fractures
Xray
What can happen in displaced femoral shaft fracture
Substantial blood loss
Fat entering venous system causing embolism
-> resp distress / hypoxia / confusion
Management of femoral shaft fractures
- Thomas splint for temporary stabilisation
- closed reduction + IM nail / plate fixation
Subtrochanteric (proximal femur) fracture often occurs in
Osteoporotic bone in elderly
What are the issues with subtrochanteric fractures
It takes a long time to heal and Non-union often occurs due to poor blood supply to the area
Management of subtrochanteric fracture
- Thomas splint for initial stabilisation
- IM nail
What type of joint is the knee joint
Hinge type of synovial joint
Movements of the knee joint
Flexion
Extension
Small degree of internal and external rotation
Articulating surfaces of the knee joint
2 between femur and tibia
1 between femur and patella
What type of bone is patella
Sesamoid bone - bone embedded in tendon / muscle
The patella is embedded in which tendon
Quadriceps tendon
The joint capsule of the knee is supported by ligaments. What are the ligaments of the knee
Patellar ligament
Lateral collateral ligament
Medial collateral ligament
Anterior cruciate ligament
Posterior cruciate ligament
Which ligaments of the knee joints are intracapsular
Anterior and posterior cruciate ligaments
Name A-D
A- Lateral collateral ligament
B- Anterior cruciate ligament
C- Posterior cruciate ligament
D- Medial collateral ligament
Name A-H
A- iliotibial band
B- Anterior cruciate ligament
C- Menisci
D- Fibula
E- Quadricep muscles
F- Patella
G- Patellar ligament
H- Tibia
Apart from ligaments, what else helps support the knee
Iliotibial band
Attachment of anterior cruciate ligament
From the intercondylar region of tibia, blends with medial epicondyle of tibia
Ascends posteriorly and attaches to the lateral femoral epicondyle
Attachment of posterior cruciate ligament
From the posterior intercondylar region of the tibia
Ascends anteriorly and attach to the medial femoral condyle
Function of MCL
resists valgus stress (force from lateral side)
Function of LCL
Resist varus stress (force from medial side)
Resist posterior-lateral rotation of the knee
Function of ACL
Resists internal rotation of the tibia in extension (bones of the knee joint twist in opposite directions)
Prevent anterior subluxation of tibia (so tibia won’t move forward)
Function of PCL
Resists posterior subluxation of the tibia
Prevents hyperextension of the knee
Function of menisci
Shock absorbers
Distribute the load of weight evenly across the knee joint
What is special about medial menisci
It is attached to medial collateral ligament which makes it more likely to be damaged (damage to MCL often causes damage to medial meniscus)
Name A-D
A- Suprapatellar bursa
B- Prepatellar bursa
C- Infrapatellar bursa
D- Semimembranous bursa
Clinical significance of suprapatellar bursa
Abnormal fluid within the knee joint can fill in here causing visible swelling
The extensor mechanism of the knee describes
Quadricep muscles and tendon
Patella
Patellar ligament
The extensor mechanism of the knee is responsible for
leg extension at the knee
Distal femur fracture often occurs in
Osteoporotic bone
Injury mechanism of distal femur fracture
Fall onto flexed knee in osteoporotic bone
The knee of the patient with distal femur fracture is often
Flexed (cannot extend it)
Investigation of distal femur fracture
Xray - AP and lateral
Management of distal femur fracture
Fixed with plate and screws
Why is true knee dislocation a medical emergency
Due to its high chance of neurovascular injuries and compartment syndrome
True knee dislocation management
Multi‐ligament reconstruction (because in order for the knee to dislocate, all the ligaments must be broken)
Most common presentation of patellar dislocation
Lateral dislocation
Patellar dislocation is most common in
Teenagers ,female
Risk factors for patellar dislocation
Ligamentous laxity
Valgus alignment of the knee
Shallow trochlear groove
Symptoms of patellar dislocation
Pain and tenderness medially where the patellar ligament is torn
Clinical signs of patellar dislocation
Haemarthrosis (swelling)
Positive patellar apprehension test
What is haemarthrosis
Bleeding into synovial membrane
Describe the patellar apprehension test
- patient in supine / sitting up with knee flexed 30 degrees
- try to displace the patella laterally
Pain = positive
Investigations for patellar dislocations
Patellar apprehension test
Xray
What may be seen on xray for patellar dislocation
Lipohaemarthrosis
Associated osteochondral fracture
Management for patellar dislocation
Most spontaneously reduce when the knee is straightened
Splint
Physiotherapy
How likely are patients going to experience another patellar dislocation after one
10% experience another recurrent dislocation
How to prevent further recurrent dislocations of the patella
Physio to strengthen quadriceps
Risk decreases with as they grow older
Surgery
What can cause tibial plateau fractures to occur
High energy injury in young
Low energy injury in old osteoporotic bone
Tibial plateau fracture is classified by
Schatzker system
Tibial plateau fracture is an intra/extra-articular fracture
Intra-articular
Different presentations of tibial plateau fractures
split in the bone
a depression of the articular surface
a combination of both