Fractures

Question 1

DDx of Limb Pain

Answer 1

• bone/periosteum:stress fracture, stress syndrome
• muscle/tendon: tendinosis, compartment syndrome
• vascular: atherosclerosis, artery entrapment
• somatic referred pain,
• neoplasm: osteosarcoma, Ewing sarcoma
• infection: osteomyelitis, septic arthritis, bursitis

Question 2

Medial Tibial Stress Syndrome (MTSS)

Answer 2

• a stress reaction of the tibia that usually precedes a stress fracture
• “shin splints”
• characterized by diffuse pain with activity
• X-rays are usually normal (possibly some thickening)

Question 3

Tibial Stress Fracture

Answer 3

• the end result of MTSS

- pain is more focal than in MTSS

Question 4

Tendonosis

Answer 4

• non-inflammatory damage to a tendon
• usually affects Achilles’ tendon in runners and patellar tendon in jumpers
• treat with eccentric exercise

Question 5

Which compartment of the lower limb is most commonly affected by compartment syndrome?

Answer 5

• the anterior compartment

Question 6

What are the most common sites of stress fractures?

Answer 6

• tibia > metatarsals > fibula > navicular bones

Question 7

What is the most common large organ traumatic injury?

Answer 7

• fractures!

Question 8

How do fractures heal?

Answer 8

• basic pathway: hematoma –> soft callus (unmineralized cartilage) –> fibrous tissue –> hard callus (secondary bone) –> hard callus (remodeled bone)
• there is an initial anabolic phase (recruitment and differentiation of stem cells) followed by a catabolic phase (cycles of remodeling to return bone to original structure)

Question 9

How common are stress fractures in infants?

Answer 9

• uncommon! these are very rare until adolescence

Question 10

Most common fracture in children is the:

Answer 10

• clavicle

Question 11

What are some general complications of fractures? Complications related to the fracture itself?

Answer 11

• general: shock, crush syndrome, DVT, PE, compartment syndrome, tetanus, gas gangrene, fat embolism
• of the fracture: delayed union, malunion, non-union, avascular necrosis (AVN), growth disturbances, myositis ossificans, joint stiffness, arthritis

Question 12

What is crush syndrome?

Answer 12

• a complication of trauma

- large release of myoglobin from the death of large muscle bulk can cause acute renal failure

Question 13

Where can fat embolisms deposit? What complications can they cause?

Answer 13

• (fat is releases from the marrow into the circulation at the time of a fracture)
• lungs (ARDS), brain (encephalopathy), kidneys (hematuria, lipiduria), skin (rash)

Question 14

What is compartment syndrome? What is the normal pressure of a compartment? How do we treat it?

Answer 14

• elevated pressure in the non-expansile fascial compartments can lead to ischemia and death of the limb
• normal compartment pressure is 7-12 mmHg, and up to about 20 mmHg is OK; when the pressure approaches 40 mmHg, ischemia is almost inevitable
• treat with dual fasciotomy and leaving the incisions open

Question 15

Tetanus

Answer 15

• tetanus is an infection of dead tissue (the organisms involved are obligate anaerobes: Clostridium tetany)
• the toxin produced by the organism causes contractures initially of the face and jaw, and then progresses to the trunk where it eventually affects the respiratory muscles = death via asphyxiation

Question 16

Which bones are more susceptible to avascular necrosis? Which muscles are more susceptible to myositis ossificans?

Answer 16

• AVN: neck of the femur, neck of the talus, proximal scaphoid
• MO: brachialis and quadriceps muscles

Question 17

Gas Gangrene

Answer 17

• potential complication of fractured and gangrenous bone
• invasion of gangrenous tissue (usually the leg) with Clostridium perfringens (“perfringens PERForates a gangrenous leg”)

Question 18

What is pseudoarthrosis?

Answer 18

• when the fractured bone moves and cartilage forms a new joint