Reverse Total Shoulder

Question 1

in a reverse, where is the center of rotation?

Answer 1

medialized and inferiorized

- allows deltoid to act on a longer fulcrum and have more mechanical advantage

Question 2

indications for reverse:

Answer 2

• pseudoparalysis
• CTA
• anterosuperior escape
• acute 3- or 4- part elderly fractures
• cuff insufficiency equivalent
• failed anatomic
• RA (if bone stock is sufficient)

Question 3

contraindications for reverse:

Answer 3

• deltoid deficiency
• axillary nerve palsy
• bony acromion deficiency
• glenoid osteoporosis
• active infection

Question 4

if there is ER deficiency, in addition to reverse, you can do:

Answer 4

latissimus transfer

Question 5

how much retroversion for a reverse?

Answer 5

0-30 degrees of retroversion for the humeral stem

• > 10 degrees increases the risk of dislocation…
• french study demonstrated neutral version is optimal for ADL function

Question 6

what is expected 10 year survivorship for rTSA?

Answer 6

90%

Question 7

what is scapular notching?

Answer 7

impingement of the medial rim of the humerosocket onto the scapula during adduction
- risk increased with superiorly placed glenosphere, insufficient tilt of the glenoid component on the native glenoid

Question 8

most common cause of prosthetic failure is?

Answer 8

glenosphere loosening

- treat with staged procedure to fill the glenoid vault with bone graft and await incorporation

Question 9

Sirveau classification of scapular notching

Answer 9

1: limited to scapular pillar
2: in contact with the inferior screw of the baseplate
3: beyond the inferior screw
4: extending under the baseplate approaching the central peg

Question 10

Causes of prosthetic instability?

Answer 10

• excessive medialization
• underestimation of humeral shortening

basically, length and offset!

Question 11

2nd most common cause of complication in rTSA?

Answer 11

humeral loosening and derotation

Question 12

How can you decrease the rates of glenoid baseplate loosening?

Answer 12

• ensure adequate inferior tilt of the baseplate
• locking peripheral 5.0mm screws
• use larger glenosphere to tighten patulous soft tissue envelope

Question 13

How should you address unstable rTSA?

Answer 13

1. get full length humerus films bilaterally
2. if humerus is short: <15mm then put in thicker poly and spacer, if >15mm then exchange the stem + bone graft
3. if humerus is medialized: <15mm put in a larger or lateralized glenosphere, if >15mm put in an exchange glenoid implant + bone graft (aka, revise the entire baseplate)

Question 14

Does subscap repair decrease rate of dislocation after rTSA?

Answer 14

yes it does idiot

Question 15

what is a modified L’Episcopo procedure?

Answer 15

latissimus dorsi and teres major transfer for ER losses

Question 16

Risk factors for rTSA instability?

Answer 16

• proximal humeral bone loss
• chronic fracture sequelae
• malunited tubersotieis
• faile prior arthroplasty
• fixed glenohumeral dislocation pre-op

Question 17

Revision following reverse TSA has the highest complications when the index procedure was performed for:

Answer 17

failed anatomic TSA

-

Question 18

what angulation of the baseplate decreseases the risk of scapular notching?

Answer 18

10 degrees inferior inclination

Question 19

How should you treat a patient with anteriosuperior escape and GH OA?

Answer 19

use a reverse TSA

Question 20

why is the reverse shoulder inherently stable:

Answer 20

radii of curvature are fully matched

- imposes concentric motion

Question 21

how does the center of rotation position help mechanics of the shoulder?

Answer 21

medialization and distalization of the glenosphere increases the efficiency of the deltoid, making its fibers function as abductors and elevators

Question 22

waht motion is most compromised after rTSA?

Answer 22

external rotation due to the mechanics forces on the deltoid

Question 23

the importance of the glenoid bone quality in RTSA?

Answer 23

should be sufficient for fixation withuot excessive anterior or posterior version, and without upward tilt of the glenoid baseplate

Question 24

what should patients be told about RTSA outcomes?

Answer 24

• complication rate is greater than conventional TSA
• radiographic results deteriorate 6 years after RTSA
• clinical results deteriorate 6-8 years after RTSA

so these are best in low demand elderly patients

Question 25

superolateral vs deltopec approach for this?

Answer 25

delto pec provies better preservation of ER

superolateral is better for post-op stability and prevents fx of the scapular spine and acromion

Question 26

considerations when placing your glenoid guidewire?

Answer 26

• baseplate shoudl sit as low as possible

- inferior border of the baseplate should not extend

Question 27

bigger vs small glenosphere components?

Answer 27

bigger demonstrates greater strength and ROMs

Question 28

what position should stability be tested for RTSA intraop?

Answer 28

adduction and internal rotation

• the position of getting up from chair or out of bed
• most common position for anterior dislocation

Question 29

waht was the most common complication of RTSA in the early psot-op period?

Answer 29

hematoma formation in the cavernous subacromial space

- drain it for 24-48 hours

Question 30

average post-op elevation after RTSA?

Answer 30

130 degrees

- should tell patients this

Question 31

RTSA vs Hemi for RA?

Answer 31

RTSA yields acceptable results even if the tuberosities don’t heal

hemi has excellent results of tuberosities heal anatomically and bad results if they don’t heal

Question 32

complication rate when converting hemis to RTSA?

Answer 32

40% revision rate
40-50% complication rate
- instability may be the most common complication

Question 33

infection rate in RTSA?

Answer 33

5% - higher than in anatomic TSA

Question 34

rates of glenoid loosening

Answer 34

4% after 2 years

Question 35

rates of inferior scapular notching?

Answer 35

50-96%

• seen within first 6 months postop and then stabilizes
• inconsistent reports of its clinical significance

Question 36

for hemiarthroplasty, results are influenced by:

Answer 36

posterior glenoid wear… concentric glenoids do better than eccentrically worn glenoids