Blue Boxes: Lower Extremity

Question 1

What bone would you use for a bone graft?

Why?

Answer 1

Fibula: Nutrient foramen is located in the middle third of the fibula in most cases, this segment of the bone is used for transplanting when the graft must include a blood supply to the medullary cavity as well as to the compact bone of the surface (via the periosteum).

Question 2

What can cause a dislocated epiphysis of the femoral head?

Answer 2

• Repetitive microtraumas that place increased shearing stress on the epiphysis
  
  • Especially w/ abduction and lateral rotation of thigh
• Epiphysis often dislocates, slowly resulting in a progressive coxa vara
• Symptoms: hip discomfort referred to knee
• Need radiographic examination to confirm diangosis

Question 3

What can cause a metatarsal fracture?

Answer 3

Heavy object falls on foot

-Common in dancers

Question 4

Femoral Fractures

Which part of the femur is most frequently fractured?

What are other common fractures?

Answer 4

• Femoral Neck Fracture
  
  • Most common
  • Weakest part of the bone
• Intertrochanteric Fracture
  
  • Due to indirect trauma (e.g. stepping of curb)
• Greater Trochanter Fractures
  
  • Due to direct trauma
• Spiral Fractures of Femoral Shaft
• Distal Femur Fractures
  
  • Separation of condyles
  • Can compromise blood supply to leg

Femur vulnerable to osteoporosis

Question 5

Tibial Fractures

Where is the most common fracture?

What other common fractures are there?

Answer 5

• Tibial Shaft Fractures: Most Common
  
  • Narrowest part
  • Poor blood supply
  • Anterior surface is subcutaneous (makes it most common site for a compound fracture)
• Transverse Stress Fractures
  
  • Distal part of tibia
  • Common with hikers
• Diagonal Fracture
  
  • Middle/Inferior part
  • Common with skiing

Question 6

How can the sesamoid bone be injured?

Answer 6

Crushing injury

Question 7

What are the most common Fibular Fractures?

Answer 7

• Distal end of lateral malleolus
  
  • Most common
• Also seen in medial malleolus

Question 8

Why are epiphysial plates more prone to injury in adolescents?

What is this type of injury called?

Answer 8

• Adolescents are still growing and the epiphysial plate are what allows the long bones to grow.
• During growth spurts, bones can grow faster than muscles.
  
  • Can result in irritation and injury to the plate and developing bone
• Also known as ostechondrosis

Question 9

Where do avulsion fractures of the hip tend to occur?

Answer 9

• Occur at Apophyses: Bony projections that lack secondary ossification centers
  
  • ASIS and AIIS
  • Ischial Tuberosities
  • Ischiopubic rami

Remember avulsion fractures occur where muscles or ligaments are attached

Question 10

What is Os Trigonum?

Answer 10

• Secondary ossification center (lateral tubercle of the talus) occasionally fails to unite with the body of the talus.
  
  • This failure may be caused by applied stress (forceful plantarflexion) during the early teens.
  • Occasionally, a partly or even fully ossified center may fracture and progress to nonunion.
• Either event may result in a bone (accessory ossicle) known as an os trigonum
  
  • Increased prevalence among soccer players and ballet dancers

Question 11

Why are tibial fractures serious in adolescents?

Answer 11

• Primary Ossification center is at superior end of tibia
  
  • Epiphysial Plate can be damaged
• Osgood-Schlatter Disease

Question 12

What is considered a pelvic and hip fracutre?

Answer 12

Hip Fracture:

• Femoral Head
• Femoral Neck
• Femoral trochanters

Pelvic Fracture: Fractures of hip bone (yes this seems counterintuitive)

• Pubic rami
• Bony pelvic ring

Question 13

How can Calcaneal Fractures happen?

What joint is normally involved?

Answer 13

Hard fall on heel (eg falling from ladder)

-Disrupts Subtalar joint

Question 14

What is the difference between Coxa Vara and Coxa Valga?

Answer 14

Coxa Vara and Valga are the angle of inclination between the long axis of the femoral neck and the femoral shaft

• Coxa Vara: angle of inclination is decreased
• Coxa Valga: angle of inclination is increased

Question 15

What can cause a fracture of the talar neck?

Answer 15

Severe Dorsiflexion of the ankle

-Body of talus can dislocate posteriorly