Low Yield

Question 1

What is the Crowe classification of adult hip dysplasia?

Answer 1

I- Less than 10% proximal migration and Less than 50% femoral head subluxation
II- 10-15% migration; 50-75% subluxation
III- 15-20% migration; 75-100% subluxation
IV- > 20% migration; > 100% subluxation

Question 2

What hip condition is responsible for 1/3 of cases of osteoarthritis?

Answer 2

Adult hip dysplasia

Question 3

Which Tonnis and Lateral center edge angles are a/w adult hip dysplasia?

Answer 3

Tonnis > 10°

LCEA less than 20°

Question 4

What complications are increased in patients with adult hip dysplasia undergoing THA?

Answer 4

1) Sciatic nerve palsy (5-15%); cannot lengthen more than 3-4cm
2) hip dislocation (5-10%)

Question 5

If multiple incisions on knee which do you take and why?

Answer 5

Most lateral.

Blood supply comes from medial side of knee

Question 6

Use of abx in cement recommended for all TKA?

Answer 6

No. Increased risk of aseptic loosening.

There is no difference in deep infection in DM

Question 7

How does an arthroplasty affect someone’s golf game?

Answer 7

Handicap will increase with TKA

Does not change with THA

Question 8

What benefit does CPM have in TKA?

Answer 8

Increased ROM at 2 weeks, no long term benefit

Question 9

Tibial tubercle osteotomy may be indicated in what revision TKA situation?

Answer 9

Patella baja.

Question 10

What precautions are needed after a rectus snip approach during revision TKA?

Answer 10

None. There is no effect on post-op outcomes of pain, ROM and function.

Question 11

Describe mechanical axis

Answer 11

Line from hip center to center of ankle.
If knee center medial- valgus knee
If knee center lateral- Varus knee

Question 12

Which axis are the femoral and tibial cuts made?

Answer 12

Perpendicular to the mechanical axis.
Femur- 5-7degree valgus cut
Tibia- 0 degree cut

Proximal tibia is 3 degree of varus so femoral component is ER 3 degrees to balance flexion gap.

Question 13

How does the relation of acetabular and femoral COR on templates affect implants?

Answer 13

If the femoral COR is lateral to acetabular COR; will decrease offset
If the femoral COR is inferior to acetabular COR; will decrease length
The converse is true of these

Question 14

The anterior Smith-Peterson approach to the hip uses a surgical plane between which of the following superficial muscles?

Answer 14

Sartorious and tensor fascia lata

Question 15

What brings about change in the surface roughness of ceramic heads leading to increased wear?

Answer 15

Zirconia crystals transform from the tetragonal phase (at implantation) to the monoclinic phase, increasing surface roughness.

Question 16

What position should a hip arthrodesis be fused?

Answer 16

20-35° of flexion
0°-5° adduction
5-10° external rotation
avoid abduction as it creates pelvic obliquity and increased back pain

Question 17

What are indications and contraindications of hip arthrodesis?

Answer 17

indications:
salvage for failed THA (most common)
young active laborers with painful unilateral ankylosis after infection or trauma
neuropathic arthropathy
tumor resection

contraindications:
active infection
severe limb-length discrepancy greater than 2.0 cm. 
bilateral hip arthritis
adjacent joint degenerative changes 
severe osteoporosis
degenerative changes in lumbar spine
contralateral THA; increased failure rate (40%)  in THA when there is a contralateral hip arthrodesis

Question 18

What severely impacts outcomes of hip arthrodesis conversion to THA?

Answer 18

Function of gluteus medius; obtain pre-op EMG