Chapter 75 - Arthritis and Arthroplasty of the Shoulder Flashcards
what is often contracted in primary GH arthritis
anterior capsule, and subscap
pathoanatomy of primary GH arthritis
POSTERIOR glenoid and humeral head wear
walch classification of glenohumeral arthritis
A: concentric wear
A1. minor wear
A2. major central erosion
B: posterior wear
B1. narrowing of the posterior joint space
B2. asymmetric loading -> biconcave glenoid
B3. monoconcave and severely worn - at least 15deg retroversion, at least 70% posterior humeral head subluxation
C: dysplastic glenoid with glenoid retroversion (not acquired) >30deg
C1. monoconcave
C2. high pathologic retroversion with acquired posterior bone loss -> appearance of biconcave glenoid
D: any level of glenoid anteversion
hemiarthroplasty v aTSA for GH arthritis
pain relief and function (ROM) are generally good but less predictable
pain relief following TSA more predictable than HA
indications for aTSA in GH arthritis
intact deltoid
intact or repairable cuff
indications for rTSA in GH arthritis
non-repairable cuff
which has higher 10yr survival aTSA or rTSA
aTSA (92-95% vs 78-89%)
complication for aTSA vs rTSA
aTSA: glenoid loosening
rTSA: instability/dislocation
optimal position for shoulder arthrodesis
30FE
30Abd
30IR
common complaint post shoulder arthrodesis
pain at the scapulothoracic jcn
what is the maximum amount of glenoid retroversion that can be corrected with high side reaming?
15deg
normal GH position in space
glenoid is 3degrees retroverted (can range from 10 of retro to 10 of ante)
humerus is 20-30 degrees of retroversion
top of the humeral head should be 8-10mm above the GT
humeral thickness should be 70% of the component diameter
Hydroxyapatite crystals
seen in RCA
dx with alizarin red staining
Gout crystals
monosodium urate crystals
negatively birefringent needle shaped crystals
pseudogout crystals
calcium pyrophosphate dihydrate
positively birefringent
rhomboid shaped
pattern of GH arthritis in RA
severe medial, concentric wear of the glenoid
what type of humeral prosthesis should be avoided in inflammatory arthropathy?
long stemmed humeral implants bc of likelihood of TEA in the future -> stress riser
most common location of osteonecrosis of the humeral head?
superior middle portion of the head -> just deep to the articular cartilage
what is the dominant source of vascularity to the humeral head?
posterior circumflex humeral a
Historically thought to be the ascending branch of the anterior circumflex humeral a via the arcuate a to the GT
what imaging do you need if you confirm ON to the humeral head?
XRs of the hips
Femoral head is most common location of ON, humeral head is 2nd
treatment for stage I or II shoulder ON
stage I and II are PRE collapse (I - no XR evident disease only MRI, II - sclerosis on XR)
core decompression
treatment for stage III, IV shoulder ON
Stage III - subchondral fracture/crescent sign
Stage IV femoral head collapse with joint incongruity at the GH joint without glenoid changes
hemiarthroplasty
treatement for stage v shoulder ON
TSA - now you have glenoid involvement