Knee Arthroplasty

Question 1

Risk Factors

Answer 1

Overweight, sports-related injury, genetics

Question 2

Indications for knee arthroplasty

Answer 2

Knee OA, RA, osteonecrosis, sig. functional limitations and pain related to degeneration, failed response to conservative treatment

Question 3

Fixation options

Answer 3

Cemented, non-cemented, hybrid (usually cemented tibial and patellar components, non-cemented femur components)

Question 4

What are the advantages of a unicompartmental KA?

Answer 4

-Cruciate ligaments retained
- Fewer surgical risks
- Less blood loss
- Faster recovery/less overall pain

Question 5

How does a patient quality for unicompartmental KA?

Answer 5

• OA in one compartment (non-inflammatory)
• Returning to low-impact job/sport
• Minimal varus or valgus
• Intact ACL
• Flexion contracture (<15deg)
• No symptomatic patellofemoral problems
• No symptoms related to the contralateral compartment
• BMI <32 ideally

Question 6

T/F all bicompartmental and tricompartmental KA involve the removal of the PCL?

Answer 6

False (PCL sparing surgeries are possible!)

Question 7

When is a revision arthroplasty indicated?

Answer 7

complication of initial procedure

Question 8

What surgical approach is gold standard for KA?

Answer 8

Medial parapatellar

Question 9

Advantages of medial parapatellar KA

Answer 9

Great exposure for surgeon
Optimal alignment

Question 10

Disadvantages of medial parapatellar KA

Answer 10

Compromises quad muscle-tendon (greater quad weakness post-op)

Question 11

Subvastus advantages

Answer 11

-Spares quad
-Better immediate post-op flexion
-less post-op pain
-Higer pt satisfaction
- Better patellar tracking
-Faster ADL recoverySubvastus advantages

Question 12

Subvastus disadvantages

Answer 12

More technically complicated (more skill for surgeon)

Question 13

Midvastus advantages

Answer 13

minimizes quad trauma

Question 14

Midvastus advantages

Answer 14

-Disrupts VMO
-No evidence to suggest any better outcomes than paramedian

Question 15

Lateral advantages

Answer 15

• great exposure to structures that may need to be released.
• Allows for correction of malalignment

Question 16

Lateral disadvantages

Answer 16

Less medial visualization
More technically complicated

Question 17

Minimally invasive advantages

Answer 17

avoids quad trauma
Avoids patellar disruption

Question 18

Minimally invasive disadvantages

Answer 18

Greater technical challenge = higher incidence of:
- Implant malpositioning
-Delayed wound healing
- Periprosothetic fractures
- Patellar fractures
-Infection
- Peroneal nerve palsy

Question 19

Potential Post op complications

Answer 19

DVT, PE, Infection, Hardware malfunction, mechanical loosening, arthrofibrosis, patellar subluxation, fracture, nerve/vascular injury

Question 20

Arththrofibrosis has the best outcomes with MUA if administer within ___________ post-op

Answer 20

3 months

Question 21

Outcome Predictors for KA

Answer 21

-Pre-op ROM/quad strength
- BMI
- Greater complications risk w/DM, Cirrhosis, HepC
- Lesser self-report outcomes: chronic pain conditions, depression +/- anxiety

Question 22

When is a pt typically d/c following TKA?

Answer 22

Same day as Sx

Question 23

What is the typical WB status of a TKA pt?

Answer 23

WBAT

Question 24

________ ROM in the first week post-op is indicative of total ROM return post-TKA.

Answer 24

Extension

Question 25

What is the one intervention NOT recommended for TKA pts?

Answer 25

Continuous passive motion (CPM)

Question 26

Under which circumstances would you NOT perform tibiofemoral mobs on a TKA pt?

Answer 26

when PCL was sacrificed