Reverse Total Shoulder Flashcards
(36 cards)
in a reverse, where is the center of rotation?
medialized and inferiorized
- allows deltoid to act on a longer fulcrum and have more mechanical advantage
indications for reverse:
- pseudoparalysis
- CTA
- anterosuperior escape
- acute 3- or 4- part elderly fractures
- cuff insufficiency equivalent
- failed anatomic
- RA (if bone stock is sufficient)
contraindications for reverse:
- deltoid deficiency
- axillary nerve palsy
- bony acromion deficiency
- glenoid osteoporosis
- active infection
if there is ER deficiency, in addition to reverse, you can do:
latissimus transfer
how much retroversion for a reverse?
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
what is expected 10 year survivorship for rTSA?
90%
what is scapular notching?
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
most common cause of prosthetic failure is?
glenosphere loosening
- treat with staged procedure to fill the glenoid vault with bone graft and await incorporation
Sirveau classification of scapular notching
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
Causes of prosthetic instability?
- excessive medialization
- underestimation of humeral shortening
basically, length and offset!
2nd most common cause of complication in rTSA?
humeral loosening and derotation
How can you decrease the rates of glenoid baseplate loosening?
- ensure adequate inferior tilt of the baseplate
- locking peripheral 5.0mm screws
- use larger glenosphere to tighten patulous soft tissue envelope
How should you address unstable rTSA?
- get full length humerus films bilaterally
- if humerus is short: <15mm then put in thicker poly and spacer, if >15mm then exchange the stem + bone graft
- 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)
Does subscap repair decrease rate of dislocation after rTSA?
yes it does idiot
what is a modified L’Episcopo procedure?
latissimus dorsi and teres major transfer for ER losses
Risk factors for rTSA instability?
- proximal humeral bone loss
- chronic fracture sequelae
- malunited tubersotieis
- faile prior arthroplasty
- fixed glenohumeral dislocation pre-op
Revision following reverse TSA has the highest complications when the index procedure was performed for:
failed anatomic TSA
-
what angulation of the baseplate decreseases the risk of scapular notching?
10 degrees inferior inclination
How should you treat a patient with anteriosuperior escape and GH OA?
use a reverse TSA
why is the reverse shoulder inherently stable:
radii of curvature are fully matched
- imposes concentric motion
how does the center of rotation position help mechanics of the shoulder?
medialization and distalization of the glenosphere increases the efficiency of the deltoid, making its fibers function as abductors and elevators
waht motion is most compromised after rTSA?
external rotation due to the mechanics forces on the deltoid
the importance of the glenoid bone quality in RTSA?
should be sufficient for fixation withuot excessive anterior or posterior version, and without upward tilt of the glenoid baseplate
what should patients be told about RTSA outcomes?
- 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
