Chapter 8- Gunshot Injuries Of Bone And Joint

Question 1

How are firearm injuries classified

Answer 1

Firearm injuries are classified as caused by:

• High velocity weapon (>920 m/sec)
• Low velocity weapon (300-600 m/sec)
• Shotgun

Question 2

What factors effect the amount of damage to soft tissue and bone resulting from a bullet?

Answer 2

• projectile mass
• Projectile velocity
• Tissue density
• Projectile design

Question 3

What injuries do the low velocity bullets cause

Answer 3

direct laceration and crushing

Question 4

Which tissues are less susceptible to damage by bullets

Answer 4

Low density tissues (lung, fat, muscle) are not as easily damaged as denser tissues of bone and solid organs. However, bone injury is the least of the problems as the soft tissues will bear the brunt of the damage caused.

Question 5

How can the soft tissue component of a gunshot injury be divided?

Answer 5

Primary bullet track, surrounded by zone of contusion and a wider zone of concussion

Question 6

What is the main difference between high velocity and low velocity injuries

Answer 6

• High velocity injuries cause a bigger track and cavitation due to the shock wave accompanying the bullet
• Resulting in greater soft tissue damage at some distance from the bullet track and dramatic injury to bone
• Soft tissue envelope is usually at least partially preserved in low velocity injuries

Question 7

What is the usual management of shotgun wounds

Answer 7

• Thorough debridement , during which the wadding backing the the shotgun pellets must be sought and removed
• Pellet removal is only indicated if proven to be intra-articular

Question 8

What are the concerns when a bullet is in or near the joint

Answer 8

• Articular damage by the bullet
• mechanical blockade to movement
• Lead arthropathy and systemic lead absorption
• Infection if the bullet remains within the joint or is in communication with the synovium

Question 9

What should be checked on examination of a gunshot injury

Answer 9

• Where is the entry wound
• Is there an exit wound
• Do the number of entry and exit wounds correspond or is there a bullet in patient
• What track did the bullet follow
• What is the neurovascular status of the affected limb

Question 10

Management of soft tissue injury in gunshot injury

Answer 10

• High velocity: aggressive debridement of all devitalised tissue and debris
• Low velocity: debride skin edges only. only remove isolated bullet fragments from the soft tissue injury unless they are causing impingement

Question 11

Management of long bone injury

Answer 11

-Surgery:
Soft tissue injury: local debridement of contused and devitalised skin
Bone: internal or external fixation to stabilise the bone
-Medication:
Attenuated tetanus toxoid 0.5 ml stat
prophylactic antibiotics

Question 12

management of superficial joint injury

Answer 12

-Superficial: if joint has been traversed by bullet or has bullet lodged in it- washed out and metallic fragments removed

Question 13

When should a deep joint be washed out

Answer 13

• Fracture of the acetabulum or femoral neck/ head on plain films
• No fracture and straight films are equivocal, perform arthrogram, any intra-articular metal is removed
• Bullets which have traversed the abdomen and may have been contaminated by bowel or bladder

Question 14

When should you remove a bullet in a deep joint

Answer 14

• Demonstrated to be intra-articualar

- Has passed through the bowel (even if not near the joint)

Question 15

When should a bullet be removed in the spine

Answer 15

• lies in spinal canal

- Has passed through abdomen