Elbow/shoulder

Question 1

joints of the shoulder

Answer 1

glenohumeral joint
acromioclavicular joint
sternoclavicular joint
scapulothoracil joint

Question 2

4 rotator cuff muscles

Answer 2

supraspinatus
infraspinatus
teres minor
subscapularis

Question 3

hemiarthoplasty

Answer 3

replacement of humeral head only

Question 4

TSA

Answer 4

total replacement
head and glenoid

Question 5

reversed shoulder replacement

Answer 5

bearing surfaces have an opposite profile to the normal anatomy

Question 6

prereqs for replacement

Answer 6

intact rotator cuff and functional
small tears okay

Question 7

contraindictions

Answer 7

non-functioning deltoid
non-functioning rotator cuff

Question 8

TSA comps

Answer 8

stemmed humeral component
- humoral head
- humeral stem
glenoid component

Question 9

glenoid component

Answer 9

concaved implant made with entirely of polyethylene
multiple pegs for bone insertion
fixed with cement

Question 10

when is glenoid replaced

Answer 10

if chondral surface is completely worn out
glenoid loosening primary failure mode

Question 11

when to use cement

Answer 11

when bone is poor quality
preexisting bone deformity
stabilizes fragments

Question 12

Shoulder resurfacing implants

Answer 12

younger active patients
rotator cuff tears
previous fractures fixed with nail or plate

Question 13

advantages of resurfacing

Answer 13

bone preservation
doesnt involve humeral neck osteotomy
shorter operation
lower fracture risk
easier revision

Question 14

when can u not perform resurfacing

Answer 14

severe osteoporosis
proximal humeral fracture

Question 15

reversed shoulder replacement

Answer 15

rotator cuff tear
rheumatoid arthritis
revision for failed hemiarthroplasty or TSA
proximal humerus fractures

Question 16

torn rotator cuff

Answer 16

-massive tear leaves muscles non functional
l-ong head of bicep is usually torn too in severe cases
-the deltoid force act as a shear force wrt the glenoid and draws humeral head superiorly
- leads to wear of humoral head and superior glenoid

Question 17

Reversed SA design comps

Answer 17

-humeral comp is stemmed implant w poly cup
- stem can be fixed to bone w cement or cementless
- semi constrained and further non anatomical humeral head shaft angle of 155
- glenoid comp consists of a large metal ball attached to metal base plate
- base plate is fixed to glenoid with screws
- humeral cup covers less than half of the glenosphere

Question 18

mechanics of rsa

Answer 18

translates the COR medially and distally
lowers the humerus relative to the glenoid

Question 19

limitation of rsa

Answer 19

unable to restore external rotation due to infraspinatus and teres minor deficiency

Question 20

elbow joints

Answer 20

humero-ulnar
humeroradial
proximal radio-unlar

Question 21

TEA components

Answer 21

metal stem
hinge
poly liner

Question 22

unconstrained or unlinked comps

Answer 22

requires competent collateral and soft tissue envelope
good bone quality
precise alignment required
instability most common failure

Question 23

Sem constrained or linked comps

Answer 23

sloppy hinge allows for some varus-valgus and rotational laxity
reduces stress on bone - cement interface
best results
early humeral loosening common when no interior flange