Tiffany's Arthroplasty Cards

Question 1

What proportion of all hip OA is due to hip dysplasia?

Answer 1

1/3

Question 2

When examining an adult w a dysplastic hip, how do you assess for impingement?

Answer 2

Impingement test: pain w flexion, adduction and IR (FADIR)

Question 3

When examining an adult w a dysplastic hip, how do you assess for anterior instability?

Answer 3

Anterior apprehension test. Examine in lateral decubitus or prone position. Abduction, hyperextension, and ER (Ab-HEER)

Question 4

In an adult w hip dysplasia, what XR findings should you look for? (6)

Answer 4

AP view
1. Tonnis angle
2. Cross-over sign
3. Lateral CEA
4. Coxa valga
5. Hip lateralization
False profile view
6. Anterior CEA

Question 5

What is the Tonnis angle?

Answer 5

On AP XR, similar to acetabular index. Measures inclination of acetab
Angle from medial to lateral sourcil, compared to horizontal
Normal <10deg
Abnormal >10

Question 6

When viewing a dysplastic hip XR, what does a cross-over sign suggest?

Answer 6

Either
- Acetab retroversion
- Anterior overcoverage
- Posterior deficiency

Question 7

What is the lateral center edge angle?

Answer 7

AP XR, used to assess lateral acetab coverage
Angle between
- Vertical line along center of head
- Line from center of head to lateral acetab rim
Normal is >25deg
Abnormal is <25deg

Question 8

What is the anterior center edge angle?

Answer 8

On lateral XP, used to assess anterior acetab coverage
Angle between
- Vertical line along center of head
- Line from center of head to anterior acetab rim
Normal is >25deg
Abnormal is <25deg

Question 9

What is the most common pelvic osteotomy used for adult hip dysplasia?

Answer 9

PAO

Question 10

What preop XR should you take before doing a PAO for adult hip dysplasia?

Answer 10

Flexion, abduction, and IR XR
Confirm congruency w planned osteotomy

Question 11

What secondary pathology can result from overcorrection during PAO for adult hip dysplasia? What should you do intraop to minimize this complication?

Answer 11

FAI (cam impingement)
Intraop XR in 90deg flexion and 15deg IR to assess for FAI after pelvic osteotomy. Determine if proximal femoral osteotomy needed

Question 12

What is the survivorship of the hip after PAO, before conversion to THA is needed?

Answer 12

90% at 15yrs
75% at 20yrs

Question 13

RC: 20F is healthy, not obese and active. She has DDH and is getting a PAO. All are true except:
A. She cannot return to recreational sports
B. 5% risk of sciatic n palsy
C. She can have a vaginal delivery in the future
D. Risk of conversion to THA is 10% at 15yrs

Answer 13

Answer: A
She can indeed return to sports
Risk of nerve injuries range from 0 - 15% in studies apparently
She can have a vaginal delivery. 90% PAO survivorship at 15yrs