Shoulder Arthroplasty Flashcards
1
Q
Indications for shoulder replacement
A
- osteoarthritis
- Rheumatoid Arthritis
- traumatic arthritis
- osteonecrosis
- rotator cuff arthropathy
- capsulorrhaphy arthritis
- proximal humeral fracture
2
Q
prosthesis design
A
- an excessively thick prosthetic head will overstuff the joint decreasing ROM and increasing strain on the subscapularis
- neck to shaft angle affects the available humeral articular surface that contacts the glenoid during ROM
- lateral humeral offset (distance btwn the lateral base of the coracoid to the lateral margin of the greater tuberosity)
3
Q
prosthesis design success
A
success depends on a combination of things:
- anatomic design
- biomechanical function
- adequate fixation
- component durability
- soft tissue balance restoration
- surgeon skill
4
Q
prosthetic design pt 2
A
- the glenoid component is designed to match the corresponding humeral head size and radius, which is typically a radius curvature larger than the humeral head
- an arthritic glenoid is oval shaped rather than pear shaped. thus, the glenoid component is oval shaped and made of polyethylene or plyethylene with a metal backed base
- the polyethylene component backing consists of a keel or multiple peg design that is cemented into the glenoid bone base
5
Q
component fixation
A
- the humeral component is placed in approximately 30 deg of retroversion and is implanted by the cemented or press fit technique (tight jam fit)
- the incidence of aseptic loosening of humeral component is low with the cemented technique
- the glenoid component is fixed in a neutral position with respect to the scapula
- glenoid component failure is the most common reason for component-related revision arthroplasty
6
Q
constrained design
A
- the constrained prosthesis was developed to create a more stable fulcrum for rotation of the shoulder when the rotator cuff is deficient
- constrained designs attempt to restore the ball and socket relationship
- in the reverse ball and socket prosthesis, the center of rotation is medialized and moved distally, increasing the moment arm of the deltoid
7
Q
physical examination
A
- inspection (movement based, drainage, oozing, integumentary
- range of motion and strength
- outcome measures
- imaging studies
8
Q
choice of implant
A
- hemiarthroplasty (single part replacement)
- total shoulder arthroplasty
- reverse shoulder arthroplasty
9
Q
operative technique: hemiarthroplasty
A
- most common is the deltopectoral approach
- incision is made just lateral to the coracoid process obliquely along the deltopectoral inverval down to the lateral border of the biceps muscle
- the subscapularis and anterior capsule are detached directly off or 2 cm medial to the lesser tuberosity or by osteotomy of the lesser tuberosity
- the anterior capsule is incised to reveal the GH joint
- the humeral head is then dislocated anteriorly and loose bodies and osteophytes are removed
- the arthritic humeral head is cut with a saw at 45 deg inclination from the axis of humerus and 30 deg of retroversion
- intramedullary canal is reamed to accommodate the largest stem size possible
- a trial implant is placed with testing for proper fit
- the subscapularis and/or the rotator cuff are repaired
10
Q
operative technique: total shoulder arthroplasty
A
- similar to HA, but requires preparation of the glenoid surface
- after humeral head is cut, the capsule is further relased anteroinferiorly to post. to allow the humeral shaft to be retracted post.
- the glenoid is reamed to remove sclerotic bone and obtain a bed of punctate bleeding
- the glenoid is prepared for cementing the plyethylene glenoid component with a keel or peg base. once the glenoid is well fixed, the humeral head component preparation follows as with HA
11
Q
operative technique: reverse total shoulder arthroplasty
A
- the deltopectoral approach is commonly used for the rTSA procedure
- the humeral head is cut and the glenoid is prepared by using sequential cannulated reamers for insertion of the baseplate, which is fixed in place with cortical screws
- the glenosphere is then stabilized to the baseplate
- the subscapularis is repaired with sutures through bone tunnels in the lesser tuberosity
12
Q
postoperative rehab: things to consider
A
- principles of rehab
- program for intact rotator cuff
- special considerations for tissue deficiency
- reverse total shoulder considerations
13
Q
rehab TSA: phase 1
A
- allow early healing of capsule
- increase PROM
- decrease shoulder pain
- retard muscle atrophy and prevent rotator cuff inhibition
- isometric concentration to increase stability
14
Q
rehab TSA: phase 2
A
- improve dynamic stabilization and strength
- imrpove ROM
- decrease pain/inflammation
- increase functional activities
15
Q
rehab TSA: phase 3
A
activity phase
- improve strength shoulder musculature
- neuromuscular control of shoulder complex
- improve functional activities
