Lower Extremity

Question 1

What is the major blood supply to the pelvis?

Answer 1

Internal iliac artery: branches at SI joints forma nastomotic rich arterial bed. Damaged in posterior arch fractures.
- Posterior: Superior gluteal à commonly injured in posterior arch fractures
- Anterior: Obturator & Internal Pudental à injured in pubic rami fractures

Venous system: arranged in plexus, tightly adherent to pelvic walls. Responsible for significant hemorrhage

Question 2

Describe the Tile classification (Box 55-1) of pelvic fractures

Answer 2

Type A: Stable, posterior arch intact
- Avulsion fracture
- Isolated iliac wing
- Pubic Rami fractures
- Minimally displaced ring fracture
- Transverse # sacrum, coccyx

Type B: Partially stable, incomplete disruption post arch
- AP injuries (Open book)
- Lateral compression injuries
- Unilateral or bilateral
- Rotationally unstable, vertically stable

Type C: Unstable, complete disruption posterior arch
- Iliac, SI, vertical sacral injuries from vertical shearing forces
- Unilateral or bilateral
- Rotationally and vertically unstable

Question 3

Evidence of posterior arch # (Box 55.3):

Answer 3

a. Presence of anterior #
b. Lumbar TP # (esp L5)
c. Ischial spine avulsion # à sacrospinous insertion
d. Sacral avulsion # lower lateral lip à insertion sacrotuberous
e. Vertical sacral fracture
f. Displaced pubic rami #
Loss of sacral foramen alignment

Question 4

List 5 indications for retrograde urethrogram (should be performed after CT)

Answer 4

• Blood at the meatus
• Gross hematuria
• Scrotal hematoma
• High riding prostate
  Inability to void

Question 5

What sacral fractures are at particular risk of neurologic injury?

Answer 5

• Transverse fracture at or above S4
• Vertical sacral # à can see cauda equina
• Fractures medial to foramina involving spinal canal
  Acetabular fractures

Question 6

What is the treatment of avulsion fractures of the pelvis?

Answer 6

• 2cm displacement:
  o May benefit from ORIF
  o More non-union if left alone

Question 7

What are common injuries associated with acetabular fractures?

Answer 7

• Sciatic nerve injnury

- Posterior hip dislocation (with posterior rim #)

Question 8

What is the blood supply to the femoral head?

Answer 8

• Ascending cervical artery, from lateral circumflex femoral artery (major source)
  - Intraosseous cervical vessels (minor)
  - Foveal artery (++minor)

Question 9

What are risk factors for AVN of femoral head

Answer 9

- Risk factors:
			o Chronic corticosteroid therapy
			o Chronic EtOH
			o Chronic pancreatitis
			o Hemoglobinopathy
			o Dysbarism
			o HIV infection (Rx vs virus?)
			o > 12 hrs to reduction of post hip dislocation
			o Femoral neck # post repair (11-20%)

Question 10

How does AVN of femoral head present?

Answer 10

• Atraumatic pain to buttox, hip, thigh or knee
  - Traumatic: subacute complication of dislocation or #
  - Bilateral 40-80%, mean age 38 yo

Question 11

What are risk factors for myositis ossificans?

Answer 11

• Trauma à direct blow to muscle
  - Post hip surgery
  - Bleeding diastasis: hemophilia, vWB disease, anticoagulated

Question 12

Describe mgmt of femoral neck fracture

Answer 12

egardless of amount of displacement, all will become unstable and require ORIF

Question 13

Describe mgmt of intertrochanteric femoral fracture

Answer 13

• Classified by # fracture parts (1-3)
• Can lose significant blood from these fractures (3L)
• All require ortho and ORIF

Question 14

Describe mgmt of Isolated trochanter fractures

Answer 14

Ortho in ED, some can be managed conservatively

Question 15

Describe mgmt ofSubtrochanteric (proximal 5cm shaft)

Answer 15

• Manage blood loss

- All require operative repair

Question 16

List complications of proximal femoral fractures:

Answer 16

- Local:
			o AVN
			o Osteomyelitis
			o Septic arthritis
			o Non-union
		- Systemic:
			o VTE (all should be anticoagulated for 10/7)
			o Fat embolism

Question 17

What are the typical positions of the patient’s leg with posterior and anterior hip dislocation?

Answer 17

Posterior:
- Hip flexed, adducted, and internally rotated
Lesser trichanter superimposed on shaft

Anterior:
- Hip flexed, abducted, and external rotation

Question 18

What specifically can you look for on Xray so you don’t miss the dislocation?

Answer 18

Posterior: Lesser trochanter not seen, femoral head smaller, abN shenton’s line

Anterior: Lesser trochanter seen in profile, femoral head larger and abN shenton’s line

Question 19

What nerves are commonly injured in hip dislocations and how do you test for them.

Answer 19

• Sciatic palsy: 10% manifests as peroneal nerve palsy with weakness of extensor hallucis longus and dorsiflexion weakness and parasthesias over dorsum of foot

Question 20

List techniques for reducing posterior hip dislocations.

Answer 20

• Stimson
  - Traction-countertraction
  - Whistler
  - Allis
  - Rochester

Question 21

List complications of supracondylar, condylar, and intracondylar distal femur fractures.

Answer 21

fat embolism
thrombophlebitis
delayed union/malunion
OA
angular deformities
intraarticular/quadricepts adhesions

Question 22

What is the management of tibial plateau fractures?

Answer 22

- Minimally displaced 4mm
	o Local compression
	o Split compression
	o Total compression
	o Split
	o Rim avulsion or compression
	o Bicondylar

Question 23

List 4 factors that determine prognosis of tibial plateau fractures.

Answer 23

1. Degree of articular depression
   
   2. Extent of separation of the condylar fracture line
   3. Diaphyseal-metaphyseal cominution and dissociation
   4. Integrity of the soft tissue envelope (open – closed)

Question 24

A fracture of the anterior tibial eminence in children and adults is the equivalent of what ligamentous injury?

Answer 24

• ACL tear

Question 25

What proportion of knee dislocations result in vascular injury?

Answer 25

• 5 – 65%

Note: foot pulses present in 5-15% popliteal artery injuries

Question 26

List 5 complications associated with traumatic knee dislocations:

Answer 26

DVT 
pseudoaneurysm
arterial thrombosis
compartment syndrome
heterotropic ossification

Question 27

List signs and symptoms of extensor disruption.

Answer 27

1. Acute onset of pain, swelling, and ecchymosis over the anterior aspect of the knee and palpable defect in the patella, quadriceps tendon or patellar tendon
   
   2. Loss or limited ability for active extension (extensor lag in last 10º of extension)
   3. High riding patella (patella alta) – Patella tendon rupture
      Low riding patella (patella baja) – Quadriceps tendon rupture

Question 28

What are the Ottawa ankle and foot rules?

Answer 28

Ottawa ankle rule: X-rays are required if there is pain in the malleolar region and any of:
1. Bone tenderness at the posterior edge of the distal 6cm or the tip of the lateral malleolus
2. Bone tenderness at the posterior edge of the distal 6cm or the tip of the medial malleolus
3. Inability to weight bear 4 steps immediately after the injury and at the time of evaluation

Ottawa foot rule: X-rays are required if there is pain in the midfoot region and any of:
1. Bone tenderness at the navicular bone
2. Bone tenderness at the base of the fifth metatarsal
3. Inability to weight bear 4 steps immediately and at the time of evaluation

List limitations of the Ottawa ankle rules.
4. Do not apply to subacute or chronic injuries
5. Do not apply to pediatrics
6. Only apply to inversion and “rolled ankle” injuries
7. Do not apply to the forefoot or hind foot
8. Do not apply to multiply injured, intoxicated or otherwise difficult to assess patients