Transcript Reverse Total Shoulder Arthroplasty

Reverse Total Shoulder
Arthroplasty
Reza Omid, M.D.
Assistant Professor Orthopaedic Surgery
Shoulder & Elbow Reconstruction
Sports Medicine
Keck School of Medicine of USC
Incidence of RC Tears with
Osteoarthritis
5-10%
Glenohumeral OA
Glenohumeral OA
• Glenoid cartilage is typically
spared anteriorly
• Wear is more pronounced
posteriorly with appearance of a
“biconcave glenoid”.
Where Does Glenoid Wear
Occur in RCT Arthropathy
Where Does Glenoid Wear
Occur in RCT Arthropathy
REVERSE TSA
Indications for RTSA
• Rotator cuff dysfunction
• Proximal humerus fractures
• Glenoid bone loss
• Revision TSA
Reverse TSA
• Predictable outcome
• Best TSA or Hemi is better than
the best reverse
• Best indication is CTA
• Worst indication is revision
arthroplasty
• Not a good option if good FE
REVERSE TSA
Two Types:
• Lateralized
• Initial design of the 70’s but abandoned
• Frankle design recently
• Medialized
• Grammont design 1991
• Most common design (zimmer, tornier, depuy, etc)
How Does A Reverse Work?
1) Medialization/Lateralization
2) Distalization
3) Semiconstrained
Biomechanics
1. Medialization converst the
shear force to a compressive
force at the baseplate/glenoid
interface.
2. Distalization tensions deltoid
3. Semiconstraint nature
overcomes deficient cuff
Medialization
Distalization
Constraint
• Under active conditions, a
mismatch of 4mm was found to
produce translations (1-2mm)
that most closely reproduced
those observed with the original
anatomy
• (Williams JOR 1996:14(6):986993).
Constraint
Benefits of Lateralization
• Improved ER/IR
• Improved deltoid contour
• Less notching
Benefits of Medialization
• Biomechanically superior
(compression force at baseplate
glenoid interface)
Integra Reverse Shoulder System
Central Screw
Peripheral Screws
Baseplate
Glenosphere
Humeral Insert
Humeral Body
Stem
Glenosphere
Glenospheres made of CoCr
38mm diameter
Many options to varying patient anatomy, increase
ROM and prevent scapular notching
– Concentric Glenosphere, 2mm Lateralized
– Concentric Glenosphere, 5mm Lateralized
– 4mm Eccentric Glenosphere, 2mm Lateralized
– 4mm Eccentric Glenosphere, 5mm Lateralized
– 4mm Eccentric Glenosphere, Inferior Hooded 2mm
Lateralized
Glenosphere Positioning
Lateralizing the C.O.R. = increased ROM,
increased internal/external, decreased
scapula notching.
Eccentric = ideal baseplate positioning while
allowing the glenosphere to be position
inferiorly and avoid scapular notching.
Increases deltoid tension.
Both options together + multiple humeral
body heights allow us to have only one
diameter Glenosphere (38mm).
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Baseplate and Screws
Glenoid baseplates made of Ti with
Asymmatrix porous coating
– 15mm length post (primary cases)
– 25mm length post (revision and bone grafting)
length options
– Curved back (convex) – anatomic shape
Baseplate and Screws
Central Compression Screw
– 5.5mm x (20-45mm) length in 5mm increments
– Independent compression screw in various length adds for
central compression of baseplate into glenoid
Peripheral polyaxial locking screws
– 4.5mm x (15-55mm) length in 5mm increments
– Anterior and Posterior are compression screws
– Superior and Inferior are compression and then locked
(Variable Angle Locking Screws)
Reverse Body
• Reverse Humeral Body made of Ti with
Asymmatrix porous coating
• 142 degree inclination angle
– Decreases scapular notching versus a 155 degree
inclination
– Increased glenoid access
• Polished medial calcar to allow for tuberosity and
soft tissue suture retention.
• Asymmatrix coating allows for good secondary
fixation and allows for all press fit humeral
component.
• Morse taper and backup screw for body to stem
connection
• 3 body height options
– Small (30mm)
– Standard (35mm)
– Large (40mm)
Humeral Poly Liners & Stems
Humeral insert made of UHMWPe
– Standard - +0mm, +3mm, +6mm, +9mm
– Retentive - +0mm, +3mm, +6mm, +9mm
» Retentive option provides more glenosphere
coverage providing more stability yet
increased chance for scapular notching.
• Humeral Stems made from Ti for
press fit applications
– 11 sizes (6-16mm) 1mm increments
• Humeral Stems made from CoCr for
cemented applications
– 5 sizes (6-14mm) 2mm increments
Surgical Technique
Humeral Preparation
Stem Sizing & Trial
142 Degree
Osteotomy
Or
Select Small Body
Humeral Preparation
Humeral Reaming
Reamer
Body
Inserter
Humeral Body
Trial and Inserter
Glenoid Preparation
Baseplate Glenoid Wire Guide
Glenosphere Glenoid Wire Guide
Or
Glenoid Preparation
Glenoid Reaming
Baseplate Boss Drilling
Baseplate Insertion
Baseplate Screw Fixation
5.5 Central Screw Preparation
4.5 Peripheral Screw Preparation and Locking Caps
Peripheral Reamers and Trialing
Glenosphere and Body/Stem Insertion
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Case
60 yo RHD s/p fall
Challenge Case
Extended Peg
6 Weeks Post-Op