Elbow/shoulder Flashcards
joints of the shoulder
glenohumeral joint
acromioclavicular joint
sternoclavicular joint
scapulothoracil joint
4 rotator cuff muscles
supraspinatus
infraspinatus
teres minor
subscapularis
hemiarthoplasty
replacement of humeral head only
TSA
total replacement
head and glenoid
reversed shoulder replacement
bearing surfaces have an opposite profile to the normal anatomy
prereqs for replacement
intact rotator cuff and functional
small tears okay
contraindictions
non-functioning deltoid
non-functioning rotator cuff
TSA comps
stemmed humeral component
- humoral head
- humeral stem
glenoid component
glenoid component
concaved implant made with entirely of polyethylene
multiple pegs for bone insertion
fixed with cement
when is glenoid replaced
if chondral surface is completely worn out
glenoid loosening primary failure mode
when to use cement
when bone is poor quality
preexisting bone deformity
stabilizes fragments
Shoulder resurfacing implants
younger active patients
rotator cuff tears
previous fractures fixed with nail or plate
advantages of resurfacing
bone preservation
doesnt involve humeral neck osteotomy
shorter operation
lower fracture risk
easier revision
when can u not perform resurfacing
severe osteoporosis
proximal humeral fracture
reversed shoulder replacement
rotator cuff tear
rheumatoid arthritis
revision for failed hemiarthroplasty or TSA
proximal humerus fractures
torn rotator cuff
-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
Reversed SA design comps
-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
mechanics of rsa
translates the COR medially and distally
lowers the humerus relative to the glenoid
limitation of rsa
unable to restore external rotation due to infraspinatus and teres minor deficiency
elbow joints
humero-ulnar
humeroradial
proximal radio-unlar
TEA components
metal stem
hinge
poly liner
unconstrained or unlinked comps
requires competent collateral and soft tissue envelope
good bone quality
precise alignment required
instability most common failure
Sem constrained or linked comps
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
