MSK: Trauma and Overuse, General

Question 1

What are the two types of stress fracture?

Answer 1

• Fatigue fracture (abnormal stress on normal bone)
• Insufficiency fracture (normal stress on abnormal bone)

Note: Stress fractures result from the mismatch of bone strength and CHRONIC mechanical force.

Question 2

Pathologic fracture

Answer 2

Fracture of a bone due to weakening of that bone (underlying lytic lesion such as myeloma met or aneurysmal bone cyst)

Question 3

Compound fracture

Answer 3

AKA open fracture: A fracture associated with an open wound (e.g. bone protrudes through the skin)

Note: These typically go to the OR for reduction and washout (due to risk of infection).

Question 4

Tuft fracture

Answer 4

A fracture of the distal phalanx tip, often with disruption of the nail plate

Note: If there is disruption of the nail plate, then this is a type of compound (open) fracture and the pt should get antibiotics (they usually don’t go to the OR, unlike other compound fractures).

Question 5

What are the phases of fracture healing?

Answer 5

• Inflammatory
• Reparative
• Remodeling

Question 6

When does granulation tissue start forming around a fracture?

Answer 6

7-14 days after fracture

Note: The fracture will appear more lucent at this time due to bone resorption. This is why some radiologists put “consider repeat in 7-14 days” if they are worried there may be an occult fracture (e.g. scaphoid fracture).

Question 7

How long does it take fractures to heal?

Answer 7

In general, 6-8 weeks (location dependent)

Note: Healing is fastest in the phalanges (~3 weeks) and slowest in the tibia/femur (~2-3 months).

Question 8

What factors are needed for proper healing to occur?

Answer 8

• Fracture stability
• Good blood supply
• Proper nutrition

Question 9

What are the major categories of abnormal fracture healing?

Answer 9

• Delayed union (e.g. twice as long as expected)
• Non-union (not healed after 6-9 months)
• Mal-union (fracture healed but bones are in poor anatomic position)

Question 10

Salient risk factors for abnormal fracture healing

Answer 10

• Vitamin D deficiency
• Gastric bypass (due to altered calcium absorption)
• Drugs/meds (tobacco use, NSAIDS, prednisone)

Question 11

What is considered the compressive side vs tensile side of a bone?

Answer 11

Question 12

Which has a better prognosis: fractures of the compressive side of a bone or fractures of the tensile side of a bone?

Answer 12

Fractures of the compressive side of a bone do better (normal physiology compresses the fracture fragments back together)

Note: Normal physiology pulls fractures on the tensile side apart, making it more difficult to heal.

Question 13

What is the most common site for a stress fracture in a young athlete?

Answer 13

Tibia (most commonly on the posteromedial “compressive” side)

Question 14

Answer 14

Anterior tibial stress fractures

Note: These are on the tensile side of the bone and often don’t heal.

Question 15

What is the compressive side of the tibia?

Answer 15

The posteromedial side

Note: This is the most common location for stress fractures.

Question 16

What is the compressive side of the femoral neck?

Answer 16

The medial side

Question 17

Are femoral neck stress fractures more common along the medial or lateral side?

Answer 17

Fractures along the compressive medial side are more common in younger pts

Fractures along the tensile lateral side are more common in older pts

Question 18

Answer 18

Stress fracture along the compressive (medial) side of the femoral neck

Note: This type of femoral neck fracture is more common in younger pts.

Question 19

Spontaneous osteonecrosis of the knee

Answer 19

An insufficiency fracture of the knee, classically associated with sudden pain after rising from a seated position in elderly females or in pts with prior meniscal surgeries

Note: This is an insufficiency fracture NOT osteonecrosis.

Question 20

Sudden pain after rising from a seated position

Answer 20

Subchondral insufficiency fracture (AKA SONK/spontaneous osteonecrosis of the knee)

Question 21

What is the most common location for spontaneous osteonecrosis of the knee?

Answer 21

The medial femoral condyle (area of maximum weight bearing)

Question 22

Acute onset pain while getting out of a car

Answer 22

Think subchondral insufficiency fracture (AKA SONK/spontaneous osteonecrosis of the knee)

Question 23

Answer 23

Calcaneal stress fracture

Note: Look for linear sclerosis that is perpendicular to the trabeculae.

Question 24

What is the most commonly fractured tarsal bone?

Answer 24

The calcaneus

Note: Calcaneal stress fractures are very common.

Question 25

Are calcaneal fractures more commonly intra-articular or extra-articular?

Answer 25

Intra-articular (75%)

Question 26

Answer 26

Navicular stress fracture (navicular is high risk for avascular necrosis, just like the scaphoid) Note: These are common in runners who run on hard surfaces.

Question 27

Military recruit

Answer 27

March fracture of the 4th metatarsal Note: March fractures are metatarsal stress fractures due to walking/marching/running long distances.

Question 28

Are femoral neck stress fractures high or low risk for abnormal healing?

Answer 28

High risk (if on the tensile lateral side) Low risk (if on the compressive medial side)

Question 29

Are patellar fractures high or low risk for abnormal healing?

Answer 29

High risk (if transverse patellar fracture) Low risk (if longitudinal patellar fracture)

Question 30

Are tibial stress fractures high or low risk for abnormal healing?

Answer 30

High risk (if along the anterior "tensile" midshaft) Low risk (if along the posteromedial "compressive" side)

Question 31

Are metatarsal stress fractures high or low risk for abnormal healing?

Answer 31

High risk (5th metatarsal) Low risk (2nd and 3rd metatarsal)

Question 32

Which tarsal bone stress fractures are high risk for abnormal healing?

Answer 32

- Talus - Navicular Note: The calcaneus is low risk.

Question 33

Is a great toe sesamoid fracture high risk or low risk for abnormal healing?

Answer 33

High risk

Question 34

How can you tell whether a lateral wrist radiograph is truly lateral?

Answer 34

The palmar cortex of the pisiform should be located centrally between the palmar cortex of the scaphoid and the capitate

Question 35

Lateral wrist radiograph anatomy

Answer 35

Scaphoid

Question 36

Answer 36

Lunate

Question 37

Answer 37

Capitate

Question 38

Answer 38

Triquetrum

Question 39

Answer 39

Trapezoid

Question 40

Answer 40

Trapezium

Question 41

Answer 41

Pisiform

Question 42

Answer 42

Hamate