Knee Injuries

Question 1

How to manage patellar dislocation?

Answer 1

1. Analgesia
2. Flex the hip
3. Gently extend the knee, guiding the patella back into place
   - should result in immediate pain relief
4. Warn patients they will have some residual soreness

Question 2

Post patellar reduction, what is the source of the soreness?

Answer 2

the medial patellaofemoral retinacular tissue

Question 3

Post patellar knee reduction, you still need?

Answer 3

Post reduction xr.
- exclude fracture

Question 4

Discharge instruction and equipment for patellar dislocation

Answer 4

Knee immobilizer
Crutches

F/u with orthopedic in 1 week

Partial weight bearing and straight leg raises to strengthen quadriceps

Question 5

What is the clinical presentation for knee (tibiofemoral) dislocation?

Answer 5

Primarily young males
MOI:
- high velocity mechanism (MVC, fall from height)
- low velocity (martial arts, trampoline falls)
- walking if morbidly obese (spontaneous)

Question 6

Types of knee (tibiofemoral) dislocations and their prevalence

Answer 6

MC: Anterior dislocation (40%)
Posterior (33%)
Lateral (18%)
LC Medial (4%)

Question 7

Patient with a severely injured knee that is unstable in multiple directions?

Answer 7

Suspect spontaneously reduced knee
- up to 50% will self reduce and then become unstable as above

Question 8

Key to favorable outcomes for knee (tibiofemoral) dislocation?

Answer 8

Timely reduction is essential

Hospitalization with emergent ortho and vascular surgeon consultation

Question 9

How to reduce tibiofemoral knee dislocation?

Answer 9

1. Check neuro-vascular status
2. Apply longitudinal traction
3. Recheck neuro-vascular status
   - document NV status
4. Splint lower extremity with knee at 20 degrees of flexion after dislocation reduction

Question 10

Why hospitalize reduced knee (tibiofemoral) dislocations?

Answer 10

They need:
- serial neuro-vascular exams and ankle brachial index exams

Question 11

ABI (ankle brachial index) parameters

Answer 11

Distal pulses before and after and ABI of >/=0.9 - observe with serial NV exams x 24hrs

asymmetric distal pulse, ABI <9 or vascular injury concern, need CT angiogram or angiography
- (ischemia, hemorrhage, hematoma)

Question 12

Knee dislocation (tibiofemoral)
- absent pulse before reduction and return of pulse post reduction need?

Answer 12

ABI and emergent vascular surgery consultation

Question 13

Knee dislocation (tibiofemoral)
- indications for emergent vascular surgery consultation for open surgical exploration and possible angiography in OR?

Answer 13

• open knee dislocation
• absent distal pulse after reduction
  -or-
• vascular inj signs

Question 14

Complications for poorly managed tibiofemoral knee dislocations?

Answer 14

popliteal artery injury

Peritoneal nerve injury

Question 15

What causes popliteal artery injury?

Answer 15

Fractures
Ligamentous inj
Dislocation

Question 16

Why is popliteal artery injury a problem?

Answer 16

If circulation is not restored w/in 8 hrs will lead to amputation
- collateral circulation is insufficient to maintain blood flow to the leg

Question 17

What causes popliteal nerve injury?

Answer 17

Several ligamentous injury or knee dislocation can lead to stress or transection of the artery